FOREWORD This Shop Manual i s a servicing guide for the CB125, CL125, CB175 and CL175. The Manual has been prepared using the CB175 and CL175 as the basic models, however, the information contained will apply equally well to all models. There are minor differences among the models, primarily in the engines ; these differences have been specificially noted for the C8125 and CL125. This Shop Manua! is applicable to all model serial numbers shown below and subsequent. CB 12% 1 - Engine No. 20000 1 1 Frame No. 2000000- CB 125K2 (General Export Type1 Engine No. 3000001Frame NO. 3000001 - CB 125K3 (General Export Type) Engine Frame Engine CL 125K 1 Frame No. No. No. No. 4000001 -4000001 2000001 2000001 CL 1 25K3 (General Export Type) Engine No. 400000 1 Frame No. 4000001 Engine Frame Engine Frame Engine Frame Engine Frame Engine Frame Engine Frame ---- ---- No. 100000 1 No. 1000001 No. 4000001 No. 4000001 No. 5000001 No. 5000001 NO. 1000001No. 1000001No. 4000001 No. 4000001No. 5000001 -NO. 5000001 - To ensure proper servicing, the special tools must be used and all repairs made to the specified tolerances. The information peculiar to CB/CL125, 175 revised models is compiled at the back of this publication as a supplement. June 25, 1974 H O N D A MOTOR CO., LTD. Service Publication Office FEATURES ENGINE 1. Chain driven overhead camshaft Assures quieter operation, due to the silent chain drive, and a more efficient higher speed engine resulting from the elimination of power loss. 2. Dual oil filtering system Provides only highly cleaned oil to lubricate the moving parts of the engine t o greatly extend the trouble free engine life. 3. Constant-meshed transmission gears Make possible smooth and effortless gear change. 4. Variable venturi carburetor Provides economical operation and greater power output at all speeds. FRAME 1. The frame main unit i s made of welded high strength steel tubing of backbone design for lightness and rugged service. 2. Front wheel i s mounted on an oil dampened telescoping fork which provides superb handling and good stability. Rear wheel is on a swing arm pivoted about plain bearings for increase rigidity and suspended on cushions provided with three stage load adjustments. 3. The CL models have a wide raised handle mounted on rubber for comfort. Semi- raised handle is mounted on the CB models. 4. Block tread pattern tire i s installed on the rear wheel of the CL models for good road holding on bad roads. 5. All lights are used throughout for greater safety, and their operating switches are all mounted on the handle bar where they are accessible without moving the hands. 6. Front wheel brake i s of the two leadings type for greatest braking efficiency. 7. All protruding parts are designed with generous radius and sharp corners have been eliminated t o prevent injuries to the rider. CONTENTS . 1 SPECIFICATIONS .................................................. 2 . SPECIAL TOOLS .................................................. CB175. CL175 .................................................. CB125. CL125 .................................................. 3 . ENGINE (CB175. CL175) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Engine Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Engine construction ...................................... B. Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Cylinder Head and Cylinder .................................... 1 . Cylinder head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . Cylinder head cover and breather . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . Camshaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . Rocker arm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . Valve seat ................................................ A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 . Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Left Crankcase Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . Left crankcase cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . A.C generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction ............................................ B. Disassembly ............................................ C . Reassembly ............................................ 3 . Starting sprocket and clutch .................................. 32 A . Construction ............................................ 32 B. Disassembly and reassembly (Starting clutch) .................. 32 C . Disassembly and reassembly (Starting sprocket) ................ 33 4 . Clutch adjuster and neutral switcn rotor . . . . . . . . . . . . . . . . . . . . . . . . 33 A . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 B. Disassembly and reassembly (Clutch adiusterl . . . . . . . . . . . . . . . . . . 33 C . Disassembly and reassembly (Neutral switch rotor) ............ 33 3.4 Right Crankcase Cover Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 1. Right crankcase cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 B. Reassembly ............................................ 34 2 . Clutch .................................................... 34 A . Description and operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 B. Disassembly ...* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 3.5 Oil Pump, Filter and Separator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 1. Oil pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2 . Oil filter .................................................. 40 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 C . Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3 . Oil separator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 A . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.6 Crankcase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 B . Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 D. Reassembly ............................................. 41 3.7 Crankshaft, Connecting Rods and Pistons . . . . . . . . . . . . . . . . . . . . . . . . 41 A . Construction ............................................ 41 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 43 2 . Connecting rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Descrpition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 B . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3 . Piston . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 B. Disnssembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4 . Piston rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 B. Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 C . Replacing the piston rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 3.8 Cam Chain Tensioner and Cam Chain Guide Roller ................ 48 A . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 .............................................. C . Inspection D. Reassembly E . Cam chain tension adiustment .............................. 3.9 Transmission.................................................. A . Description ............................................ B. Disassembly ............................................ C . Inspection .............................................. D. Reassembly ............................................ 3.10 Gear Shift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Operation .............................................. B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly ............................................ 3.1 1 Kick Starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.12 Carburetor .................................................. Construction ............................................ Function of the main components . . . . . . . . . . . . . . . . . . . . . . . . . . Adiustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Engine (CB125, CL125) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Engine Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Engine description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Cylinder Head and Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . Cylinder head. cover and breather . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . Camshaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . Rocker arm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Reassembly ........................................... 5. Valve seat ................................................ A . Description ............................................ 6 . Cylinder .................................................. A . Construction ............................................ B . Disassembly ............................................ ............................................ 49 49 49 50 50 52 52 52 53 53 53 54 54 54 55 55 55 55 56 56 58 60 62 64 64 64 65 66 66 66 66 66 67 68 68 69 69 69 69 69 69 70 70 70 70 70 71 71 71 71 72 72 72 .............................................. ............................................ L e f t Crankcase Cover ........................................ 1 . Left crankcase cover ........................................ 2. A.C. Generator ............................................ A . Construction ............................................ B. Disassembly ............................................ C . Reassembly ............................................ 3 . Clutch lifter thread .......................................... A . Description ............................................ B. Disassembly ............................................ C. Reassembly ............................................ C . Inspection D 3.3 . Reassembly ........................................ ........................................... ........................................... ............................................. . ........................................... Right crankcase cover assembly ................................ 1 . Right crankcase cover ...................................... A . Construction ............................................ B. Disassembly ............................................ C . Reassembly ............................................ 2. Clutch .................................................... A . Description and Operation ................................ B. Disassembly ............................................ C . Inspection .............................................. D . Reassembly ............................................ 3 . O i l pump ................................................ B . Disassembly ............................................ C . Inspection .............................................. D . Reassembly ............................................ 4 . Oil filter .................................................. A . Operation .............................................. B. Disassembly ............................................ C. Reassembly ............................................ Crankcase .................................................. 1 . Upper and under crankcase .................................. A . Description ............................................ B. Disassembly ............................................ C . Inspection .............................................. D . Reassembly ............................................ 2 . Oil separator .............................................. A . Description .................................. :. ........ B. Disassembly ......................................... + .. C . Reassembly ............................................ Crankshaft .................................................. A . Construction ............................................ 4 . Cam chain tensioner A . Construction B. Disassembly C . Inspection D Reassembly 3.4 3.5 3.6 2. 3. ............................................ .............................................. ............................................ ............................................ ............................................ .................................................... B. Disussembly C . Inspection D . Reassembly Connecting Rods A Disassembly Piston . ............................................ A . Description 81 B . Disassembly ............................................ 81 81 C . Inspection .............................................. D. Reassembly ............................................ 82 4 . Piston Rings ................................................ 82 B. Inspection .............................................. 82 C . Replacing the piston rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 3.7 Transmission .................................................. 83 A . Description ............................................ 83 B. Operation .............................................. 83 C . Inspection .............................................. 84 3.8 Gear shift .................................................. 84 A . Description ............................................ 84 B. Disassembly ............................................ 85 C . Inspection .............................................. 85 D. Reassembly ............................................ 85 3.9 Kick Starter .................................................. 86 A . Description ............................................ 86 B. Disassembly ............................................ 86 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 D. Reassembly ............................................ 86 3.10 Carburetor .................................................... 87 Construction ............................................ 87 Function of the main components .......................... 87 Adjustment .............................................. 87 4 . FRAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 4.1 Steering Handle .............................................. 88 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 4.2 Front Cushion ................................................ 90 A . Description ............................................ 90 B . Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 C . Inspection .............................................. 94 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 4.3 Steering Stem and Steering Handle Lock ........................ 95 A . Construction ............................................ 95 B . Disassembly ............................................ 96 C . Inspection .............................................. 97 D. Reassembly ............................................ 97 4.4 Fuel Tank .................................................... 97 A . Construction ............................................ 97 B. Disassembly ............................................ 98 C . Inspection .............................................. 98 D. Reassembly ........................................... 99 4.5 Frame Body .................................................. 99 A . Construction 99 B . Disassembly 100 100 C . Inspection D. Reassembly 100 4.6 Air Cleaner Case and Seat 100 A . Construction 100 ............................................ ............................................ .............................................. ............................................ .................................... ............................................ 5. B . Disassembly ............................................ 101 C . Inspection .............................................. 101 D. Reassembly ............................................ 101 4.7 Stand ...................................................... 101 A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 C . Inspection .............................................. 102 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 4.8 Muffler and Exhaust Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 D. Reassembly ............................................ 104 4.9 Air Cleaner and Tool Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 C . Inspection .............................................. 107 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107 4.10 Rear Fork and Rear Fender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 A . Construction ............................................ 107 B . Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 4.11 Rear Cushion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 4.12 Front Wheel ................................................ 111 A . Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1 C . Inspection .............................................. 112 D. Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 4.13 Rear Wheel .................................................. 114 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 B. Disassembly ............................................ 115 C. Inspection .............................................. 116 D. Reassembly ............................................ 117 ELECTRIC SYSTEM .................................................. 120 1 Ignition Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 A Ignition coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 B . Spark advancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 121 C . Contact breaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 E . Spark plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 2. Electrical power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 A . A.C. generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 3. Selenium rectifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 4. Battery ................................................. 126 A . Construction ............................................ 126 B. Rating ................................................ 126 C . Instruction on use and servicing ............................ 127 D. Battery charging procedure ................................ 127 E. Trouble shooting and corrective action ...................... 129 . . 5. Various loads 6. ........................................... 130 A . Headlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 B. Tail. stoplight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130 C . Neutral and speedometer lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Starting motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 A . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 B. Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 C . Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 D. Reassemly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Service tester instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 7. 6. PERIODIC ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Maintenance Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . Engine Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Measuring compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . Tappet adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . Ignition timing adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . Contact points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . Spark plug adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . Fuel supply system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 . Fuel strainer cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 . Oil filter screen cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 . Air cleaner servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. Carburetor cleaning and adjustment . . . . . . . . . . . . . . . . . . . . . . . . B. Lubricating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . Parts not requiring periodic oil change o r lubrication 2 . Engine oil change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . Drive chain adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Brake adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . Front brake adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . Rear brake adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E . Spoke torquing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F. Battery inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G . Security inspection of parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......... 6.2 138 138 138 138 138 139 140 140 141 142 142 142 143 143 143 144 144 145 145 145 145 145 147 Periodic Inspection and Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 7. TROUBLE SHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Main engine trouble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Carburetor trouble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Engine noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154 Steering system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 5 . Clutch system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 6 . Gear change system 155 7 . Suspensions 155 8 . Brake system 156 9 Drive chain 156 1. 2. 3. 4. ........................................ ................................................ .............................................. . ................................................ 8 . WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 CB125 wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 CL125 wiring diagram ...................................... 158 CB 1 75 wiring diagram ...................................... 159 CL175 wiring diagram (General export type) . . . . . . . . . . . . . . . . . . . . 160 CL175 wiring diagram (U. S . A . Export type) .................... 161 1. SPECIFICATIONS CB175 (U.S.A. ~ y p e ) 1 I I I I DIMENSION 1 1 Overall length Overall width 1 1 Overall height I Wheel base I Seat height I Ground clearance I 1 / Dry weight 1 1 1,975 177.8) 745 (29.3) 1 1 1,015 (40.01 1,275 (50.2) 1 1 145 ( 5.71 1 129 kg 1284 Ibs) 1,975 (77.8) I Same as left / I Same as lett I 1,040 (40.941 1 1,015 140.0) 1,990 (78.35) 1,280 (50.391 1 1,275 150.2) 770 (30.32) I Same as left 167 ( 6.57) I Same as left 1 Cu;b weight 127 kg 1271 lbs) I I I I Curb weight 136 kg 1299 lbs) FRAME TYpe Backbone Semi double cradle tubler type Same as left F. suspension, travel Telescopic fork Same as left Same as left R. suspension, travel Swing arm type Same as left Same as left F. tire size, type 2.50-18 (4 PR) 2.75-1 8-4 Same as left R. tire size, type 2.75-18 14 PR) 3.00-18-4 Same as left Same as left Same as left Internal expanding shoe R. brake Internal expanding shoe Fuel capacity 10.5 lit 12.8 US gal.. 2.3 Imp. gal.) Some as left 10.0 lit. 12.6 US gal.. 2.2 Imp. gal.) Fuel reserve capacity - 2.5 lit. 15.28 US pt, 4.46 Imp. pt) Same as left Caster angle Same as left Trail length Same as left Same as left ENGINE TYpe / Cylinder arrangement I I 1 Bore and stroke Displacement Compression ratio 1 I 1 Valve train I I 1 I Maximum horsepower Maximum torque Oil capacity Lubrication system I / I I Air coo!ed 4 stroke cycle I Same as left I Twin, 30" inclined from vertical / I I 1 5 2 x 4 1 (2.047X 1.615) 174 cc I10.65 cu-in) 9.0 : 1 Chain driven overhead camshaft 20.0 PS 10,000 rpm 1.5 kg-m (10.8 ft. lbs) 1.5 lit. 13.2 US pts, 2.7 Imp. pts) Forced prejsure & wet sump I Twin parollel 8O inclined from vertical Same as left Same as left Same as left Same as left / / I I Same as left Same as left Same as left / / / Same as left Some as left Same as left I I I Same as left Same as left Same as left ( Same as left Same as left ) Same as left Same as left I I I I Same as left I I I 10" Same as left 30' Same as left Intake valve Same as left Exhaust valve Same as left I 1 Valve tappet clearance Idle speed I 0.05 (0.002) I 1.200 rpm / Same as left I Same as left same as left Same as left DRIVE TRAIN 1 I I I Clutch Multiple wet plates Same as left Same as left Transmission Constant meshed gears Same as left Same as left Primary reduction 3.700 Same as left Same as left Gear ratio I 2.769 Same as left Same as left Gear ratio D: 1.882 Same as left Same as left Gear ratio III I .450 Same as left Same as left Gear ratio IV 1.173 Same as left Same as left Gear ratio V 1.000 Same as left Same as left Final reduction 2.500 2.470 Same as left Gear shift pattern Left food operated return type Same as left Same as left I I ELECTRICAL Ignition Starting system - Alternator b p a r k plug 1 / I I Battery and ignition coil Motor and kick A.C. generator rotor type D-8HS, X-22FS I 1 / / I Same as left Same as left I I Same as left I I D-8HS ( Same as left Same os left Same as left I I Same as left Same as left Same as left I I 7. C L 1 7 5 (U.S.A. SPECIFICATIONS Type) mm (in) ( DIMENSION I Overall length I Overall width 1 ( 1 / / Overall height h K 3 K 0 Item e b e 1 / 1,975 177.81 745 129.31 1 1 1,015 (40.01 'y (50.21 Seat height 1 I / 1.990 (78.31 820 (32.31 1,080 (42.51 145 1 5.71 Same as left 1 I Same as left Same as left 200 ( Same as left 7.81 Same as left 129 kg 1284 Ibsl Curb weight 124 kg (273.4 Ibsl Curb weight 136 kg (300 Ibsl Backbone Semi-double cradle tubler type Same as left F. suspension, travel Same as left Same as left R. suspension, travel Same as left Same as left 3.00-1 9-4 Same as left Dry weight I I 1,290 (50.81 790 (31.11 Ground clearance I K 4 FRAME Type F. tire size, type 2.50-18 (4 PRI 2.75-18 (4 PRI F. brake / I Internal expanding shoe ri.brake ( Internal expanding shoe tire size, type 1- ( / / 9.5 lit. (2.5 US gal., 2.1 Imp. gal.] / r 1 Caster angle Trail length 86 (3.381 I Air cooled 4 strolte cycle 1 JDisplocement L G r e s s i o n ratio I I , Twin, 30" inclined from vertical I 5 2 x 4 1 12.047X 1.6151 1 ] 174 cc (10.65 cu-in) 1 1 9.0 : 1 / Chain driven overhead valve train / 20 PS 10.000 rpm 1 1.5kg-m (10.8 ft. Ibsl 8,500 rpm ( /Oilcapacity / 1.5 lit. (3.2 US pts, 2.7 Imp. ptsl E a t i o n system 1 I I Forced pressure & wet sump ( )aximum torque I Same as left I Same as left Same as left I Same as left I I Same as left I / Same as left I / Same as left I Same as left Twin parallel 8 O inclined from vertical Same as left Same as left Same as left Same as left rnmchnft Same as left Same as left Sawe as left I 1 Maximum horsepower 1 / Bore and stroke I Same as left I I Cylinder arrangement Same as left 9.0 lit. (2.38 US gal., 1.98 Imp. gal.) 1.5 lit. (3.17 US pt, 2.64 Imp. ptl 64' / I I 3.00-18-4 Same as left / I 1 / Some as left Same as left same as left Same as left Same as left / I Same as left Same as left ( Same as left Same as left Same as left 1 I 7. SPECIFICATIONS 1 Intake valve 10" Same as left 30' Same as left Opens 40° 40' Same as left Closes lo0 10" Same as left 0.05 10.002) Same as left Same as left Exhaust valve Valve tappet clearance 1 Idle speed 1 1,200 rpm 1 same as left same as left DRIVE TRAIN I I I I I I Clutch Multiple wet plates Same as left Same as left Transmission Constant meshed gears Same as left Same as left Primary reduction 3.700 3.700 Same as left Gear ratio I 2.769 Same as left Same as left Gear ratio II 1.882 Same as left Same as left Gear ratio Ill 1.450 Same as left Same as left Gear ratio IV Same as left Same as left Gear ratio V Same as left Same as left Final reduction Gear shift pattern 1 I 2.375 I Same as left Left foot operated return type ( Same as ieft I / Same as left Same as leit ELECTRICAL Ignition Battery and ignition coil Same as left Same as left Starting system Motor and kick Same as left Same as left Alternator Battery capacity Spark plug I / 1 A.C. generator rotor type 12V-9AH 0-8HS, X-22FS I / I Same as left Same as lest D-8HS / / 1 Same as left Same as left Same as left I I I I I I 7. Item SPECIFICATIONS K 0 K 3 K 2 DIMENSION Overall length 1.975 (77.81 Same as left 1,980 177.95) Overall width 745 (29.31 Same as left Same as left Overall height 990 (39.01 Same as left 1,040 (40.941 Wheel base 1,275 150.21 Same as left 1,280 (50.391 Seat height - 780 130.71 - Ground clearance 145 1 5.71 Same as left 115 kg 1253.6 Ibsl Dry weight 790 131.101 - 140 ( 5.511 Curb weight 118 kg 1260.2 Ibsl Curb weight 1I 9 kg 1262.4 Ibsl Same as left Semi double cradle tubler type FRAME Type Backbone pipe frame F . suspension, travel Telescopic fork Same Same as left - R. suspension, travel - F. tire size, type Same 2.75-1 8-4 - as left Swing arm type Same as left Same as left 2.50-1 8-4 Same as left Same as left as left Same as left Internal expanding shoe Same as left Same as left Fuel capacity 10.5 lit. 12.8 US gal., 2.8 Imp. gal.) 10.0 lit. 12.6 US gal., 2.2 Imp. gal.) Same as left Fuel reserve capacity - 2.5 lit. 15.3 US pt. 4.4 Imp. pt) Same as left Same as left Same as left Same as left Same as left R. tire size, type F. brake Same as left Internal expanding shoe Same - R. brake Caster angle Trail length 1 ::013.391 as left ENGINE TYpe Air cooled 4 stro!:e Same as left Same as left Cylinder arrangement Twin, 30° inclined from vertical Same as left Swin parallel, from vertical Bore and stroke 4 4 x 4 1 (1.732X 1.6151 Same as left Same as left Displacement 124 cc 17.59 cu-in1 Same as left Same as left cycle Compression ratio 9.4 Same as left Same as left Valve train Chain driven overhead camshaft Same as left Same as left Maximum horsepower 15 PS/11,000 rpm Same as left 15 PS/10,000 rpm Maximum torque 1.05 kg-m 17.59 ft Ibsl 9,000 rpm Same as left 10.5 kg-m 17.59 It. Ibsl 8.500 rpm 1 2 lit. (2.5 US pts, 2.1 Imp. ptsl Same as left Same as left O i l capacity : 1 p p Lubrication system L L inclined Forced pressure & wet sump Same as left Same as left 7. I Intake valve / Opens E l SPECIFICATIONS 1 5' I 30" 1 Same as left I Same as left Same as left Same as left Opens 35O Same as left Same as left Closes 5" Same as left Same as left Exhaust valve Valve tappet clearance 0.05 (0.002) Same as left Idle speed 1,200 rpm Same as left Same as left Multiple wet plates Same as left Same as left Constant meshed gears Same as left Same as left DRIVE TRAIN Transmission I 1 I / / 1 Primary reduction Gear ratio I Gear ratio D[ 2.615 I / Same as left 1.611 ( 1.667 3.875 I Same as left / / Same as left Same as left Same as left I Gear ratio IU 1.190 Gear ratio IV 0.91 7 1.043 0.880 Same as left Final reduction 2.867 3.133 Same as left Gear shift pattern Left foot operated return type Same as left Same as left Gear ratio V I I I I I I Same as left ELECTRICAL Ignition Starting system Alternator Battery capacity Spark plug / 1 / / 1 Battery and ignition coil Motor and kick A.C. generator rotor type 6V-6AH D-8H5, X-24FS / I I 1 / Same as left Same as left Same as left 6V-12AH D-8HS / / I / / Same as left Same as left Same as left Same as left Same as left CL125 mm (in) K Item I K 2 0 K 3 DIMENSION I / Overall length I 1,930 (76.0) 830 (32.7) Same as left Overall height Wheel base I 1,270 (50.0) I Seat height 1 150 i 5.9) Ground clearance / Same as left Same as left 810 (31.89) 1,035 140.6) 1,030 140.55) Same as left 1,230 (50.39) / - I 155 Same as left ( 6.11 1 17 kg (258 Ibs) Curb weight 115 kg (253.6 Ibs) Same as left Type Backbone pipe frame Same as left Semi double cradle tubler type F. suspension, travel Telescopic fork Same as left Same as left R. suspension, travel Swing arm type Same as left Same as left F. tire size, type 2.75-1 8-4 Same as left Same as left R. tire size, type 3.00-1 8-4 Same as left Same as left F. broke Internal expanding shoe Same as left Same as left R. brake Internal expanding shoe Same as left Same as left Fuel capacity 10.5 lit. (2.8 US gal., 2.3 Imp. gal.) Dry weight FRAME - Same as left Fuel reserve capacity Caster angle Same as left 86 13.38) Trail length Same as left Same as left ENGINE Type Cylinder arrangement Displacement / I Air cooled 4 stroke cycle / Same as left / Twin, 30" inclined from vertical Same as left from vertical 4 4 x 4 1 (1.732X 1.615) Same as left Same as left 124 cc (7.59 cu-in) Same as left Same as left 1 Compression ratio 9.4 Same as left Same as left Valve train Chain driven overhead camshaft Same as left Same as left Maximum horsepower 14 PS/10,000 rpm Same as left : I Same as left I Maximum torque (7.67 ft. lbs) 8,500 rpm Same as left O i l capacity 1.2 lit. (2.5 US pts, 2.1 Imp. ptsl Same as left Same as left Lubrication system Pressure & wet sump Same as left Same as left 7. Intake valve I Opens SPECIFICATIONS Same as left 5" I Same as left I I Same as left I Exhaust valve Same as left Same as left Same as left I Same as left Same as left I Valve tappet clearance 1 0.05 10.002) I Same as left 1 Same as left I Idle speed / 1,200 rpm I Same as left I Same as left I DRIVE TRAIN I I I I Clutch Multiple wet plates Same as left Same as left Transmission Constant meshed gears Same as left Same as left Primary reduction 3.875 Same as left Same as left 2.615 Same as left Same as left Gear ratio I[ 1.61 1 Same as left Same as leit Gear ratio llI 1.190 Same as left Same as left Gear ratio IV Gear ratio V Gear ratio I I 1 / 0.917 I Same as left - - - Final reduction 3.000 3.133 Same as left Gear shift pattern Left foot operated return type Same as left Same as left ELECTRICAL / I Starting system I Alternator ( Battery capacity I Spark plug Ignition I I I / / Battery and ignition coil Motor and kick A.C. generator rotor type 6V-6AH D-8HS, X-24FS / I / / / Same as left I / Same as left Same as left / Same as left Same as left ( Same as left Saue as left I Same as left Same as left Same as left I I I I I 7. SPECIFICATION & PERFORMANCES 7. SPECIFICATION & PERFORMANCES 7. SPECIFICATION & PERFORMANCES (U!9'IP) SSOI 2. SPECIAL TOOLS 2. SPECIAL TOOLS CB125 175 ENGINE Q,ty CB/CL 125 CB/CL 175 NO. Tool No. @ 0740 1-001 0000 Gauge, float level 1 @ 07902-2000000 Spanner, pin 48 mm 1 0 07902-2400000 Spanner, pin 46 mm 1 @ 07902-2500000 Spanner, pin switch 1 (9 07908-001 0000 Wrench, tappet adjusting 1 07916-2400000 Wrench, lock nut I6 mm 1 @ 07922-2000000 Holder, drive sprocket 1 @ 07922-2350000 Holder, drive sprocket 1 Puller, rotor 1 Puller, rotor 1 0 Driver, valve guide 1 0 Remover, valve guide 1 Driver, valve guide 1 Driver, bearing 1 Driver, bearing 1 Driver, bearing 1 Driver, bearing 1 Guide, fork seal 1 Tool Description @ 07947-3550000 Guide, fork seal 1 @ 07949-2860000 Handle, bearing driver 1 @ 07954-2000000 Compressor, piston ring 1 @I 07954-2350000 Compressor, piston ring 1 @ 07957-3290000 Compressor, valve spring 1 0 0 0 0 0 0 Remarks 0 0 Main switch 0 0 0 0 0 0 Dynamo Dynamo (3 0 s 0 0 0 Front wheel 0 Front fork Rear wheel 0 0 0 0 0 0 Front fork 2. SPECIAL TOOLS 74 2. CB125 NO. 175 SPECIAL TOOLS FRAME Tool No. Tool Description Base, piston Compressor, shock absorber Slider, spring Cutter, 90° (IN) Cutter, 90' (EX) Cutter, flat Cutter, flat Cutter, interigr (IN) Cutter, interior (EX) Cutter, 90" Cutter, flat (IN) Cutter, flat (EX) Cctter, interior (IN) Cutter, interior (EX) Holder, seat cutter Holder, seat cutter Reamer, valve guide Case, seat cutter Case, special tool Cover, timing inspection Cover, timing inspection Q,ty CB/CL 1 25 CB/CL 175 Remarks 2. SPECIAL TOOLS 76 77 3. ENGINE CB/CL175 Engine assembly diagram 3.7 ENGINE 3.1 3.1 ENGINE REMOVAtL AND lNSJALLATiON 78 ENGINE REMOVAL A N D INSTALLATION A. Engine Construction All o f the models incorporate the O.H.C. design, driven from the center of the engine by a lightweight chain. This provides the engine with high speed and high power output due t o the elimination of the reciprocating movements mechanical losses, and reduction in weight. Further the chain is always maintained in a constant tension by the spring operated automatic tensioner t o assure quiet operation and precise valve timing at all speeds. The lubrication system utilizes a plunger type oil pump, driven through the transmission main shaft t o provide lubrication under pressure to all of the primary moving parts of the engine and in conjunction, a screen and a centrifugal filter are incorporated in the system to assure that only highly purified oil i s circulated within the engine to minimize the parts wear and attributing t o the extended engine life. @) Step bar Fig. 3-1. @ 8mm bolts and nuts. Removing the step bar @) Air cleaner @ 6 X 12 hex. bolt @ 5 X 16 cross screw Fia. 3-2. Removing the air cleaner B. Engine removal (CB 175 and CL 175) 1. Shut off the fuel cock at the fuel tank. 2. Remove the step bar @ by unscrewing the t w o 8 mm nuts and 8 X 25 bolts @ (8 mm bolts for CL 175). (Fig. 3-i) Remove the 6 mm nuts from the cylinder head and 8 x 3 6 bolt, and then the muffler can be separated. (CL 175 : Remove the 6 mm nuts from the cylinder head and 8 mm nut and 6 mm bolt.) 3. Remove the air cleaner cover. 4. Remove the air cleaner @ by unscrewing the two 6 X 12 bolts @ and the 5 X 16 cross screw @. (Fig. 3-2) @ Clutch cable Fig, 3-3. @ Clutch lifter thread Disconnecting the clutch cable 5. Remove the left crankcase rear cover and disconnect the clutch cable @ lower end from the clutch lifter thread @. (Fig. 3-3) 6. Rotate the rear wheel t o position the chain joint adjacent t o the drive sprocket and disconnect the drive chain @. (Fig. 3-4) @ Joint clip @ Drive chain Fig. 3-4. Disconnecting the drive chain 79 3. E N G I N E 7. Disconnect the high tension terminals from the spark plug. Remove the starting motor cable, and then disconnect all leads. (Fig. 3-5) 8. Remove the carburetor @. (Fig. 3-6) (Note) Separate the fuel tank t o facilitate the removal of the 6 mm bolts. 9. Remove the engine mounting bolts and the engine can b e freed from the frame. Fig. 3-5. Disconnecting the electrical leads @ Catburetors @ 6mm hex. bolts Fig. 3-6. Removing the carburetors eassernbly Perform the engine installation in the reverse order o f removal described in Section 3.1 B. The engine installation can be made easier by temporarily hanging the engine on the frame by the use o f the T-handle cross screw driver @ followed by the installation o f the engine mounting bolts. (Fig. 3-7) @ T-handle cross screw driver Fig. 3-7. Installing the engine (Note) When reconnecting the drive chain the joint clip should b e installed with the opening facing opposite t o the direction o f the normal drive chain. (Fig. 3-8) I @ Joint clip Fig. 3-8. Joint clip installation 3. Adiust the chain tension so that there will be 1 t o 2 cm 10.40-0.80 in1 slack at midpoint between the sprockets. 3.2 Fig. 3-9. 3.2 CYLINDER HEAD AND CYLINDER Valve mechanism CYLINDER HEAD A N D CYLINDER 1. CYLINDER HEAD A. Construction The cylinder head is a cast aluminium twin construction o f a semi-spherical combustion chamber with a squish area for better combustion efficiency. The single piece overhead camshaft, rocker arm and valve mechanism are all incorporated in the valve chamber above the combustion chamber. (Fig. 3-9, 3-10) Contact breaker assembly is mounted on the left end of the camshaft. Cylinder head cover incorporates a breather passage t o prevent the pressure build up. Fig. 3-10. Cylinder head combustion chamber 0. Disassembly 1. Drain oil from the engine. 2. Remove the kick starter pedal, right crankcase cover and cylinder head side cover. 3. Remove the gear change pedal, left crankcase cover, point cover and breaker assembly. 4. Remove the eight 8 mm blind nuts @ and 6 x 4 5 hex. bolt @ and then remove the cylinder head cover @. (Fig. 3-11) 5. Rotate the crankshaft so that the cam chain joint clip @ is toward the top of the cam sprocket and then disconnect the cam chain @. (Fig. 3-12) Attach a wire t o both ends o f the chain before disconnecting, this will simplify the assembly task later. 6. Separate the cylinder head @ 6x45 hex bolt @ Cylinder head cover @ 8 mm bind nut Fig. 3-11. Removing the cylinder head cover 20 3. E N G I N E 21 C. inspection 1. The cylinder head is exposed t o the high pressure and temperature resulting from the combustion o f the fuel mixture, further, when the head is unevenly torqued, i t may develop cracks o r warpage and will cause defective sealing between the head and the cylinder resulting in gas leak, air sucking with consequent d r o p in compression. The warpage o f the cylinder head does not develop suddenly and i t may be overlooked, therefore, caution should be exercised during reassembly since the uneven torquing o f the cylinder head is a very common fault. @ Cam chain @ Joint clip Fig. 3-12. Disconnecting the cam chain . To insoect f o r warpage - o f the cvlinder head, a.w. l v. a thin coat o f bluing o r red lead o n a surface plate and work the mating surface o f the cylinder head o n the surface plate ; the warpage can b e determined by the transfer o f the bluing o n t o the cylinder head. (Fig. 3-13) To correct the warpage, lap the cylinder head o n the surface plate with a # 2 0 0 sandpaper, finally finish b y using a # 4 0 0 sandpaper, and then inspect again with the bluing. 2. Inspect the combustion chamber, inlet and exhaust ports for cracks. 3. Inspect the valve guide and valve stem. Check the valve guide diometer at the top, center and bottom in both the X and Y axis, using a precision cylinder gauge. Check the valve stem with micrometer. @ Cylinder head @ Bluing or red lead Fig. 3-13. Checking the cylinder head for warpage If the valve guide inside diameter is beyond serviceable limit, i t may be repaired by using a reamer (Tool NO. 07008-001 01 and replacing the valve with one o f an oversize. Standard Value 5.48-5.49 mm (0.2158-0.2162 in) with in 0.02 mm Serviceable Limit Replace if under 5.46 mm (0.215 in) - (0.2165-0.21 71 in) 10.055- 10.065 mm . 10.3959-0.3963 in) 0.065 mm . 0.0410.001 6-0.0026 in) Replace if over 5.555 mm 10.21 9 in) Item Outside diameter lnlet valve Contact face runout Inside dameter lnlet valve guide Outside d:ameter Interference fit 0.01 -0.035 mm 10.0004-0.0014 in1 5.46-5.47 mm Outside d ameter (0.2150-0.2154 in) Exhaust valve with in 0.02 mm Contact face runout (0.0008 in) 5.5-5.515 mm Inside diameter 10.2165-0.21 71 in) 10.055- 1 0.065 mm Exhaust valve guid~ Outside diameter 10.3959-0.3963 in) 0.04-0.065 mm lnterference fit 10.0016-0.0026 in) 0.03-0.055 mm Exhaust valve clearance 10.0012-0.0022 in1 lnlet valve clearance . I I Replace 0.08 mm Replace 5.44 mm if over 10.028 in) if under (0.214 in1 Replace if over. 5.555 mm 10.21 9 in1 . Replace if over 0.1 mm 10.0039 in) 3.2 CYLINDER HEAD AND CYLINDER 4. When replacement of the valve guide becomes necessary, remove and replace with an oversize guide, use the vaive guide remover (Tool No. 07047-040011 and the valve guide driver (Tool No. 07046-21 60 11 for replacement operation. After installing the valve guide, use a reamer to obtain the proper valve clearance. D. Reassembly 1. Clean and inspect the cylinder head interior and exterior for cracks, damage and warpage, also inspect the head gasket, valves, valve guide and spring for satisfactory condition. Perform the head assembly in the reverse order of disassembly. 2. When installing the cylinder head to the cylinder, the cam chain should be assembled as shown in Fig. 3-14 and attention should be given to the proper valve timing. Align the "T" timing mark on the generator to the timing index mark (the piston is at top-dead-center], position the camshaft sprocket so that the "0" mark on the face of the sprocket is at the top, and then assemble the cam chain. The joint clip must be installed with the opening facing in the opposite direction to the normal chain movement. @) Center crankshaft @ Cam chain guide roller @ Tensioner push rubber @ Cam chain tensioner spring @ Tensioner set bolt @ Tensioner push bar @ Cam chain tensioner @ Cam shaft 3. If the cam chain tensioner pushbar is not completely pushed in, the cam chain cannot be connected. (Fig. 3-15) @ Tensioner set bolt @ Tensioner push bar Fig. 3-15. Pushing in the tension push bar 4. The cylinder head should be tightened uniformly with the torque wrench in the sequence shown in Fig. 3-16. (Torque : 160-210 Kg. cm (11.615.2 ft. Ib)] Fig. 3-16. Tightening sequence of the cylinder head 3, E N G I N E 23 CYLINDER HEAD COVER AND BREATHER Description A breother chamber is incorporated in the head cover which provide constant pressure within the crankcase. Further, the o i l is separated from the gas which is exhaust. As the o i l laden o i l vapor passes through the breather passage, the o i l is separated from the gas b y centrifugal force and flows d o w n the o i l passage where it is collected. (Fig. 3-17, 3-18) Fig. 3-17. Breather chamber I @ From crankcase @ Exhaust gas Fig. 3-18. Principle of breother @ Contact breaker cover @ Contact breaker assembly Fig. 3-19. Removing the contact breaker assembly @ Wooden block stopper @ Spark advancer Fig. 3-20. Removing the spark advancer I 3.2 CYllNDER HEAD AND CYLINDER @) Contact breaker point base Removing the contact breaker point base Fig. 3-21. 3. CAMSHAFT A. Construction A single piece camshaft contains both inlet and exhaust cams together with the sprocket which is mounted in the center o f the camshaft. f/z The cam sprocket is driven by the crankshaft at the speed of the crankshaft. (Fig. 3-22) I f @ Camshaft @ Tappet adjusting nut @ Rocker arm @ Rocker arm shaft The cam is provided with a long gradual rise t o prevent abrupt rise and drop of the valve, thus assuring a quieter valve operation. (Fig. 3-23) I @ Base circle @ Max cam lift @ Buffer curve @ Cam height Cam contour Fig. 3-23. 3. E N G I N E 25 B. Disassembly 1. Remove the cylinder Section 3.2.1. B. head in accordance with 2. Remove the left and right cylinder head side covers, contact breaker assembly, spark advancer and tappet adjusting hole cap. Rotate the camshaft so that both rocker arms are resting o n the heel o f the cam, in this position, disassemble the rocker arms from the head b v removing the rocker arm shofts. (Fig. 3-24) @ Valve rocker arm @ Rocker arm shaft Fig. 3-24. Removing the valve rocker arm 3. Remove the camshaft from the cylinder head. (Fig. 3-25) @ Camshaft Fig. 3-25. Removing the camshaft Fig. C. 3-26. Camshaft Inspection 1. Camshaft (Fig. 3-26) Left side diameter @ Standard Value 19.967- 19.98 mm (0.7861 -0.7866 in) 19.967- 19.98 mm (0.7861 -0,7866 Cam base circle 21.0 mm 10.827 in) Item Right end diameter Cam height D. O Serviceable Limit Reploce if under 19.947 mm (0.7853 in) Replace if under 19.947 mm (0.7853 in) 25.057 mm (0.9865 in) IN 24.871 mm (0.9792 in) EX Reassembly 1. Screw out the tappet adjusting screw and assemble the rocker arm into the cylinder head in the reverse order of disassembly. 2. Adjust the tappet clearance to 0.05mm (0.0020in) with a c o l d engine. (Note) Repair o r replace the camshaft if the cam is scored o r w o r n exessively. 3.2 26 CYLINDER HEAD AND CYLINDER 4. ROCKER ARM A. Construction The function of the rocker arm is to transpose the rotary motion of the camshaft to a reciprocating motion for actuating the valve. The rocker arm is made rigid to prevent deflection and the end which contacts the cam is finished smooth after surface hardened to minimize wear. The end which operates the valve is provided with a tappet adjusting screw that contacts the valve. (Fig. 3-27) @) Valve rocker arm B. Disassembly 1 . Disassemble the rocker arm in accordance with Section 3.2.3. 5. Fia. 3-27. @ Rocker arm shaft Rocker arm and rocker arm shaft. C. Inspection 1. Rocker arm Standard Value Serviceable Limit Replace if over 0.3mm 10.01 2 in) Replace if over Slipper sur- 2. Rocker arm shaft Item Outside dia Clearance / / Standard Value 9.972-9.987 mm 10.3926-0.3933 in1 0.01 3-0.043 mm (0.0005-0.0017 in1 I / Serviceable Limit Reoface if under 9.92 mm (0.3934 in1 Replace i f over 0.08 mm 10.0031 in1 3. Check for proper tappet clearance, (both inlet and exhaust) should be 0.05 mm (0.002 in), too small a clearance will affect the engine causing compression leak and results in hard starting. 4. Check for proper valve timing. (Fig. 3-28-1) (Refer to page 22) 5. Check to see that the cam chain is not stretched. D. Reassembly 1. Inspect the rocker arm contact surface and repair or replace if there is scoring or excessive wear. 2. If the rocker arm had been disassembled, the tappet clearance should be readjusted. Make the adjustment by positioning the piston on top-deadcenter of the compression stroke, this will free all of the valves. Align the "T" timing mark on the generator rotor to the timing index arrow mark on the stator. I I I@ Inlet valve opens 10' @ Inlet valve closes 40: @ Exhaust valve opens 40' @ Exhaust valve closes 10' Fia. 3-28-1. Valve timina diaaram. 3. Check the valve tappet clearance with the thickness gauge. (Fig. 3-28-2) @) Cylinder head cap @ Adjusting screw @ Lock nut @ Thickness gouge Fig. 3-28-2. Checking the valve tappet clearance I I 3. ENGINE 5. VALVE A. Description The valves control the volume o f inlet gas and also the exhaust gas entering and leaving the cylinder. The diameter of the exhaust valve head is made smaller for better heat radiation. lnlet valve is made large for greater volumetric efficiency. Double spring feature prevents the valves from floating during high speed operation. (Fig. 3-29) B. Disassembly @ Valve spring retainer Q Valve cotter 1. Remove the cylinder head in accordance with Section 3.2 1 B. 2. Disassemble the rocker arm from the cylinder head b y pulling out the rocker arm shaft. 3. Compress the valve spring with the valve lifter @ (Tool N o . 07957-3290000) and after removing the valve cotter, valve spring and the retainer, the valve can be removed. (Fig. 3-30) C. Inspection 1. Exhaust valve Item Length @ Stem dia Fig. 3-30. Removing the valve (Fig. 3-31) Standard Value 72.15-72.45 mm (2.8405-2.8524 in1 5.46-5.47 mm (0.2150-0.21 54 in1 0.55-0.85 mm 10.0217-0.0335 in1 Head thickness @ Concentricity Within 0.03 mm of valve face (O.OO1 Serviceable Limit Replace if under 71.75 mm 12.8248 in1 Replace if under 5.44 mm 10.21 42 in1 Replace if under 0.3 mm 10.01 18 in1 @ 2. lnlet valve Standard Value Serviceable Limit 3. Valve spring measurement Fig. 3-31. Inlet and exhast valves Outer valve spring Standard Value Serviceable Limit 18.302 Ibs) 71.883 Ibsl Inner valve spring Standard Value Item Free length 30.2 mm (1.I890 in1 Spring pressure 26.2mm/4.08-4.52kg 11.0315 in/8.9969.967 Ibsl 20.3mm/l0.9- 12:l kg (0.7992 in/24.03526.681 Ibsl Serviceable Limit Replace if under 29.7 mm 693 - - 3.2 CYLINDER HEAD AND CYLINDER Reassembly 1. Before the valve is assembled, the valve contact surface should be inspected for wear, pitting, or carbon. After cleaning, oil the valve stem, and the valve should be inserted from the combustion chamber side. 2. The valve outer and inner valve springs and retainers should be fitted from the cap hole of the tappet adjusting hole and compressed by using the valve lifter (Tool No. 07957-3290000). Secure with the valve cotters. VALVE SEAT @ Valve seat cutter @ Cylinder head Fig. 3-32. Reworking the valve seat A. Description The valve seat i s repaired with three types of cutter. The relative location and the width of the valve seat contact area is accomplished with the seat top cutter and seat bottom cutters while the refacing of the valve contact area is performed by the 90" cutter. (Fig. 3-32) Valve seat cutters Descriotion 1 Tool NO. Valve seat cutter 90° / 07980-2350 100 Flat surface seat cutter (IN) 1 07980-2350300 Flat surface seat cutter (EX) 1 Interior seat cutter (IN) [ 07980-2350500 Interior seat cutter (EX1 1 07980-2350400 07980-2350600 Valve lapping operation is performed last, this is to obtain a leak proof seal between the valve and the valve seat. Place a liberal amount of lapping compound on the valve face and lap the valves, applying a slight pressure while rotating the valve back and forth with a suction cup lapping tool. Wash off the compound thoroughly and inspect the valve seat with bluing. (Fig. 3-33) (Note) (a1 When the valve stem i s greatly worn, the valve guide is usually also worn. Hence, when a valve is replaced, it also i s desirable to replace the valve guide. Since the guide i s press fitted, it is recommended that they be replaced with an oversize guide. (bl When the valve is assembled, the compound which was used during lapping should be completely removed. Fig. 3-33. Valve seat detail Fig. 3-34. Cylinder Inspection 1. A valve seat in good condition should have a full surface contact with the valve face. Standard value : 1.0 mm (0.04 in) Serviceable limit : in excess of 2 mm (0.08inl 2. Assemble the valve into the cylinder head so that the valves are well seated, and fill the cylinder head combustion chamber with oil, inject a blast of air in from the inlet and exhaust ports and if any bubbles should appear, it is an indication that the valve seats are not completely sealed. 28 29 3. ENGINE @ 6 mm hex bolt @ Cylinder @ Upper crankcase Fig. 3-35. Removing the cylinder 2. Remove the 6 mm hex. bolt @ and then remove the cylinder @ from crankcase @. (Fig. 3-35) . Inspection 1. Measure the cylinder bore, taper, out-of-round w i t h w precision cylinder gauge. Take the measurement at the top, middle and bottom in both the X and Y axis. (Fig. 3-36) ltem Cvlinder bore / Standard Value 1 52.00-52.01 mm I Serviceable Limit / Re~airif over 1 11.969-1.9694 in) / 52:l mm (2.0512in) Repair if over / 0.005 mm 10.0002 in) / 0.05 (0.0020in) Cylinder out 1 0.005 mm 10.0002 in) 1 0.05 Repair 10.0020 over in) @ Cylinder gauge @ Cylinder Measuring the cylinder bore Fig. 3-36. toner mm of round mm if 2. The clearance between the piston and cylinder will greatly affect the engine performance. Because the piston is elliptical, the clearance is controlled very closely. The clearance are not the same, however, if any area is greater than 0.1 mm (0.004 in), the cylinder should be rebored and fitted with an oversize piston. Oversize pistons are available in 0.25, 0.50, 0.75 and 1.00 mm (0.01, 0.02, 0.03 and 0.04 in) size. 3. When removing carbon deposits from the piston top and ring grooves, care should b e exercised so as t o not cause any scratches or damages t o the piston. Fig. 3-37. 4. Measure the piston perpendicular t o the piston pin hole. (Fig. 3-37) Piston Standard Value 51.55-51.60 mm Serviceable Limit 12.046-2.047 in) 5. Measure the piston ring side clearance with a thickness gauge. (Fig. 3-38) - Item Piston @ Thickness gauge @ Piston @ Piston ring Fig. 3-38. Measuring thc piston ring side clearance Serviceable L m t Standard Value Replace ~f over 0.025-0.055 mm 10.001 -0.0022 ~ n ) 0.1 mm 10.004 in) 3.2 CYLINDER HEAD AND CYLINDER 30 6. Piston ring groove Item Bottom dia l~oo Groove Se;ond width Oil 7. Standard Value Serviceable Limit 45.9-46.0 mm (1.707- 1.81 1 in) 1.205- 1.220mm 10.047-0.048 in) 2.50-2.52 mm (0 098-0.099 in) Replace if over 1.3 mm (0.0512 in) Replace if over 2.6 mm (0.1024 in) Piston rings Measure the ring end gap by inserting the piston ring into the cylinder so that the ring is a t right angle t o the cylinder axis. (Fig. 3-39) Standard Value Item bop 1.1 65- 1.I 80 mm 10.046-0.0464 in) Ring 1.175- 1.190 mm thicknesdsecondl (0.046-8.047 in) 2.475-2.490 mm oil 10.097-0.098 in) 0.52-0.78 kg Second 11.15- 1.72 Ibsl closing 0.72- 10.08 kg force (1.59-2.22 Ibs) 0.15-0.40 mm Ring end gap 10.006-0.016 in) 1:; I 1 iing Serviceable Limit Replace if under 1.125 mm 10.0443 in) Replace if under 1.I 35 mm (0.0447 in) Replace if under 2.43 mm (0.095 7in) Replace if under 0.42 kg (0.926 Ibs) Replace if under 0.53 kg (1.1 69 Ibs) Replace if over 0.8 mm (0.0315 in) 8. Check the gaskets for damage. @ Thickness gauge @ Piston ring @ Cylinder Fia. 3-39. Measuring the piston ring end gap Replace i f any damage exists. (Note) 1. Oversize piston rings are available in four sizes; 0.25, 0.50, 0.75 and 1.00 mm (0.01, 0.02, 0.03 @ Cylinder @ Piston base @ Piston ring compressor Fig. 3-40. Installing the cylinder and 0.04 in). 2. W h e n making piston ring end gap measurement, insert the ring carefully into the cylinder t o prevent scratches or gouges t o the cylinder wall. 0. Reassembly 1. After assuring that there are no damages or excessive wear to the cylinder, assemble the cylinder in the reverse order o f disassembly. 2. Make sure that the cylinder gasket and the t w o dowel pins are installed. 3. During the installation o f the cylinder 0,use piston bases @ t o prevent piston movement, also use a ring compressor @ t o prevent ring damages. (Fig. 3-40) 4. Assemble the cylinder head and cover unit. (Note) Check t o make sure that the gaskets are properly in place. 3.3 LEFT CRANKCASE COVER 1. LEFT C R A N K C A S E C O V E R A. Construction The purpose of the crankcase is t o protect the vital components of the engine. The left crankcase houses the A.C generator stator. (Fig. 3-41, 3-42) @ Left crankcase cover Fig. 3-41. Left crankcase cover 37 3. ENGINE B. Disassembly 1. Drain the o i l from the crankcase. 2. Remove the gear change pedal. 3. A f t e r removing the mounting screws, the l e f t crankcase cover can b e separated from the crankcase. @ Clutch lifter thread @ A.C. generator stator Stator housed in the left crankcase cover Fig. 3-42. @ Clutch adjuster locking bolt Fig. 3-43. @ Clutch adjuster @ Clutch cable lower odiuster Fig. 3-44 @ Locking nut Ci) A.C. generator rotor @ A.C. generator stator A.C. generator rotor and stator Fig. 3-45. 3.3 LEFT CRANKCASE COVER case cover and the stator @ from the lett crankcase cover @. (Fig. 3-47) Fig. 3-46. Removing the A.C. generator rotor C. Reassembly 1. Assemble the A.C. generator in the reverse order of removal. (Note) Make sure that the pin is installed during mounting of the rotor. @) A.C generator stator @ L. Crankcase cover Fig. 3-47. Removing the A.C. generator stator 3. STARTING SPROCKET AND CLUTCH (CB175) A. Construction The starter armature speed is reduced by a series o f gears enclosed within the starter housing. The chain further reduces the speed and provides high torque t o turn over the crankshaft for each starting. To prevent the starter from being motorized after the engine starts, an overrunning clutch is incorporated into the A.C. generator rotor. Refer to the electrical section for details. 8. Disassembly and reassembly of the starting clutch 1. Remove the A.C. generator in accordance with section 3.3.2. B. 2. Remove three screws and remove the starting clutch. 3. Reassemble the starting clutch and A.C. generator in the reverse order of disassembly. Check to assure smoother roller operation. Check condition of side plate and guide. Check for the weak or broken clutch roller spring. I i @ Starting chain Fig. 3-48. Removing the starting chain 3. E N G I N E @ Starting motor sprocket Fig. 3-49. Starting motor sprocket The starting chain ioint clip must be installed with the open end opposite t o normal direction o f chain movement. 4. CLUTCH ADJUSTER AND NEUTRAL SWITCH ROTOR A. Operation of clutch adjuster @ Clutch lifter thread Fig. 3-50. Clutch adiuster The function o f the clutch is t o temporarily disengage the transmitting o f the power between the engine and the transmission during the period o f gear change. Clutch is operated b y the handle lever through a cable t o apply pressure which overrides the clutch springs. The clutch adiuster is set t o provide the . . proper clutch action. (Fig. 3-50, 3-51) B. Disassembly and reassembly of the clutch adjuster 1. Remove the crankcase cover in accordance with Section 3.3.1 B. 2. Remove the 6 x 3 6 bolts from the adiuster fixing plate and then remove the clutch lever spring t g separate the clutch apjuster. 3. Apply grease t o the clutch adjuster before assembly, use grease type HD multipurpose N L G l NO.2. @ 6 X 36 hex bolt @ 6 mm flat washer @ J Adjuster fixing piece @ Clutch adiuster Q Clutch lifter thread @ Left crankcase cover Fia. 3-51. Comoonents of clutch @ 6 X 12 cross screw @ Neutral switch stator @ 6 x 2 0 cross screw @ Neutral switch rotor Fig. 3-52. Removing the neutral switch rotor 3.4 RIGHT CRANKCArSE COVER ASSEMBLY 3.4 34 RIGHT CRANKCASE COVER ASSEMBLY 1. RIGHT CRANKCASE COVER A. Construction The right crankcase cover and the left crankcase cover, house the engine primary components. The oil filter cover @ is fitted to the case cover and provides the passage for lubricating oil in both directions. (Fig. 3-53) B. C. Disassembly 1. Remove the kick starter arm from the kick pinion shaft. 2. By removing the ten screws securing the case cover, the right crankcase cover can be removed. (Fig. 3-54) 3. After unscrewing the three,6 X 16 screws, the filter cover can be removed. (Caution) During operation, attention should be given to the two 74.5X3 "0" rings fitted to the filter cover to assure that there are no oil leaks. Reassembly 1. Before performing the assembly, inspect the crankcase and oil filter covers for cracks and also for any damages to the mating surfaces since they will cause oil leaks. 2. Clean the 0 rings @ and inspect for any damages. replace if necessary. (Fig. 3-55) 3. After installation of the screws, tighten them uniformly to prevent the covers from warping and consequent oil leaks. @ Right crankcase cover @ Oil filter cover Fig. 3-53. Right crankcase cover L a 6x45 screws @ 6 x 3 2 screws Fig. 3-54. Right crankcase cover screws 2. CLUTCH A. Description and o p e r a t i o n The function of the clutch is to temporarily disengage the transmitting of the rotary motion between the engine and the transmission during the gear change and then after the gear change, permit a smooth power transition. The condition of the clutch will have a varying effect on the efficiency of the power transmission. (Fig. 3-56) The clutch mechanism is of a conventional wet type multiple disc operated by the clutch lifter thread connected by a cable to the clutch lever. When the right crankcase cover is removed, the clutch complete is exposed. To the clutch outer complete, the clutch spring driving the clutch pressure plate is installed. The clutch plate is installed with the clutch friction disc between the clutch center with four 6 x 2 0 hex bolts. The clutch plate has teeth cut on the inside. These teeth are engaged with teeth cut on the outside of the clutch center. The clutch center is coupled to the transmission main shaft by spline. Hence, it and the transmission main shaft are essentially a single unit. The clutch plate, clutch center, and clutch pressure plate rotate. O n the other hand, to the groove cut on the exterior circumference of the clutch outer, the clutch friction disc is coupled by the collar entering the groove; freewheeling rotation with the transmission main shaft is obtained. Hence, while the clutch i s connected, the clutch outer center, six clutch plates, six clutch friction discs, and clutch pressure plate are essentially a single unit through friction exerted by @ 0 ring @ O i l filter cover Fig. 3-55. 0 ring and oil filter cove1 I 35 3. E N G I N E I @ Clutch rod @ Clutch outer compiete @ Clutch center @ 20mm set ring @ Clutch lifter joint piece @ Clutch plate B @ Clutch friction disc @ Clutch plate @ Clutch pressure plate @ Clutch spring @ Clutch spring retaining plate @ 6 X 20 hex bolt. Fig. 3-56. Clutch the clutch spring ; rotation o f the crankshaft is transmitted t o transmission system. W h e n the clutch lever is gripped, the clutch adjuster rotates clockwise, the adjustment thread is pushed out b y the square-headed thread i n the clutch adjuster fitted t o the left crankcase cover : this is pushed out by the clutch joint through the clutch rod. The clutch spring is compressed and the six clutch friction discs and six clutch plates become disengaged. Hence, the rotary motion o f six clutch plates and six clutch discs is not transmitted t o the clutch center. (Fig. 3-57, 3-58) @ Clutch adjuster @ Clutch lifter thread @ Clutch lifter rod Fig. 3-58. Sectio~alview of clutch adiusting thread I @ Clutch spring @ Clutch center @ Clutch plate @ Clutch outer @ Clutch lifter rod @ Clutch lifter joint piece @ Clutch friction disc Fig. 3-57. Sectional view of clutch I B. Disassembly 1. Remove the right crankcase cover. 2. Unscrew the four clutch pressure plate retainer bolts and remove the friction disc and clutch plates. 3.4 RIGHT CRANKCASE COVER ASSEMBLY 3. Remove the o i l filter r o t o r lock nut and then the o i l filter retaining lock nut t o pull the r o t o r off the crankshaft. 4. Remove the 20 mm set ring @ and remove the clutch center @. (Fig. 3-59) 5. Unscrew the o i l pump b o d y mounting nuts and separate the o i l pump from the crankcase. 6. Remove the o i l pump assembly together w i t h the clutch outer cover. (Fig. 3-60) (Caution) Pull off the clutch unit parallel t o the shaft exercisi n g care s o that the shaft is n o t damaged. @ 20 mm set ring @ Clutch center Fig. 3-59. Removing the 20 mm set-'ring C. Inspection 1. Clutch spring / ltem I Standard Value / Free length 22.5mm/15.9-18.1 kg 10.8858 in/ 35.060-39.91 1 1bs1 Load Serviceable Limit Replace if under '30.3- mm 11.1 929 in1 I .- 31.05 mm 11.2224 in1 - (Note) Use c o i l spring tester ( T o o l N o . 07134-999011 f o r testing the valve spring tension. 2. Friction disc Iten Thickness Warpage 1 / Standard Value 2.92-3.08 mm 10.1 15-0.1 21 in1 Within 0.2 mm 10.0079 in) 3. Clutch plate / Serviceable Limit Replace i f under 2.5 mm 10.0984 in1 Replace if over 0.5 mm 10.01 96 in) / Serviceable Limit 1 @ O i l pump assembly Removing the clutch outer and pump body @ Clutch outer Fig. 3-60. (Fig. 3-61) 4. Primary drive g e a r ltem Chordel distance across 3 teeth / 1 Standard Value 15.769-15.790 mm (0.6208-0.61 85 in) Replace i f under 15.739 mm @ Vernier calipers @ Clutch plate Fig. 3-61. Measuring the clutch plate thickness D. Reassembly 1. Reassemble the clutch i n the reverse o r d e r o f disassembly. 3.5 OIL PUMP, FILTER A N D SEPARATOR 1. OIL PUMP A. Description The o i l pump is a plunger type, operated b y a connecting r o d through a n eccentric cam o n the transmission main shaft. (Fig. 3-62) @ O i l filter rotor @ O i l pump Fig. 3-62. O i l pump and centrifugal filter 3. E N G I N E %t 0 0 @ 0 0 0 Camshaft Piston Connecting rod Chain tensioner Oil filter Oil pump Transmission main shaft Transmission counter shaft FigI. 3-63. Lubrication system 0 3.5 OIL PUMP, FILTER AND SEPARATOR 0 Lubrication system (Fig. 3-63) The oil i s picked up from the crankcase sump and routed through the oil passage to the oil filter where the impurities are removed by the centrifugally operating oil filter. The clean oil is then pressure fed through the upper crankcase to all the crankshaft bearing. The oil is separated into two routes, one is fed to the roller bearing and the other enters the crankshaft to lubricate the connecting rod large end through the holes drilled in the crankshaft iournals. The connecting rod small end is lubricated by oil mist. The oil from the upper crankcase oil passage is separated into two paths, one of the paths delivers oil to the top of the cylinder head through the cylinder stud bolts. This oil is fed into the camshaft from the rocker arm and lubricated. The oil lubricates the cam chain on its way down to the sump. The other oil path feeds the oil through the oil passage in the crankcase and enters the transmission t o lubricate the free gears. The other gears and bearings are lubricated by oil droplets and mists. B. Disassemble 1 . Remove the right crankcase. 2. Remove the oil filter. 3. Remove the right primary drive gear. 4. Separate the pump body toge:her with the clutch @ 26 mm c~rcltp @ Pump rod Fig. the pump rod 3-64. 5. By removing the 26 mm circltp, @ the pump rod @ can be separated from the clutch outer (Fig. 3-64) 6. Extract the pump plunger pin @ and remove the plunger @ at the tip of the pump rod (Fig. 3-65) @ Pump rod Remov~ngthe plunger @ Pump plunger Fig. 3-65. @ Pump plunger pln 39 3. E N G I N E 26 mm circlip @ Pump rod side washer @ Pump rod @ 6 x 3 6 stud @ Plunger pump pin @ Plunger @ Suction valve bolt @ Suction valve bolt packing @ Suction valve spring @ steel ball Pump body gasket Oil pump body @ Pump filter screen @ 51s" steel ball @ Valve spring @ 1 1 5 x 2 0 ring @ Outlet valve guide Pump lock washer @@ 6 mm hex nut. Fig. 3-66. Pump component parts 51s" 6 7. Component parts of oil pump. (Fig. 3-66) C. Inspection 1. The normal capacity of the oil pump is 36OOcc/minute at 10,000 rpm; if the capacily falls below 3400 cc, there is a danger of developing engine seizure, therefore the pump should be repaired or replaced. 2. Clearance of component parts Item I Standard Value I Plunger to housing I Serviceable Limit I 0.025-0.063 mm 10.001 -0.0025 in) Replace i f over 0.1 7 mm (0.0067 in1 D. Reassembly 1. Assemble the pump in the reverse order of disassembly. (Note) a. Proper operation ot the oil pump can be checked by loosening the left rear cylinder head cap nut. If oil seeps out, the lubrication is normal. b. If there is absence of oil, check the following points : (a1 Proper assembly of the pump. ibl Condition of gaskets. (cl Excessive clearance of punger. (dl Malfunction of the steel boll valve. le) Clogged screw. If) Clogged filter or oil passages. 3.6 CRANKCASE 40 2. OIL FILTER A. Description The engine oil is doubly filtered through the centrifugal filter arid the mesh screen filter to assure clean supply of oil to the engine. (Fig. 3-67) The screen filter is on the pump inlet side and the centrifugal filter is on the outlet side. B. Disassembly Remove the right crankcase cover in accordance sembly in the reverse order of disassebly. 2. Make sure that the 16 mm mounting nut is properly 1 @ Oil filter rotor @ 4 6 x 2 Oring Oil filter @ Oil filter cap Fig. 3-68. Removing the oil filter cap torqued and filter cap well seated. 3. OIL SEPARATOR A. Operation The oil separator @ is located in the forward section of the lower crankcase, directly below the crankshaft. Its primary function is to control the oil splashed by crankshaft counter weights, prevents oil penetration and controls the oil temperature. (Fig. 3- 69) @ Oil separator Fii. 3-69. Lower crankcase 3.6 CRANKCASE A. Description The upper and lower crankcases are constructed of lightweight aluminum alloy and can be separated at the center lines of the crankshaft, transmission shaft, and the kick starter spindle. In addition, the starting motor is mounted at the front section of the CB175 crankcase. In the upper surface of the upper crankcase, the cylinder stud bolts are inserted. The lower crankcase is equipped with the oil . .. separator, lower crankcase cover, and two drain plugs. (Fig. 3-70) @ Oil filter cap Fig. 3-67. @ Drain plug Fig. 3-70. Drain plugs 47 3. ENGINE Disassembly 1. Drain oil in the crankcase. 2. Remove the cylinder head and cylinder. 3. Separate the generator. left crankcase cover and AC 4. Separate the right crankcase cover, oil filter, clutch and oil pump. 5. Remove 8 mm nut and 6 mm nut from the stud bolts at the upper part of the upper crankcase. (Fig. 3-71-A) @ 8mm bolt Fig. 3-71A. @ 6mm bolt Crankcase bolt 6. Remove 8 mm nut, 6 mm bolts and 8 mm bolts from the lower crankcase. (Fig. 3-71-8) 7. Remove the two 5 X 12 cross screws and starting motor side cover, and then remove the 6 x 2 0 and 6 x 2 8 bolts on the right hand side of the crankcase which mount the starting motor. (Fig. 3-72) 8. By removing the 6 x 3 5 bolt on the left hand side at the starting motor which is supported by the crankcase, the starting motor can be removed. 9. While the key on the gear shift arm is released from the shift drum, dismount the motor. Fig. 3-718. Bolts and nuts on the lower crankcase C. Inspection - and other damages. @ 4x I3 6 hex bolt Removing the storitng motor Fia. 3-72. Apply liquid gasket to the mating surfaces of the case ; assemble after drying. 3.7 Fig. 3-73A. Crankshaft. CRANKSHAFT, CONNECTING RODS, AND PISTONS The crankshaft journals are made of high carbon steel and the counterweights are of nickel-chromemolybdenum steel, assembled by press fitting. Crankshaft is supported by three roller bearings and one ball bearing which takes the thrust load and are fixed in place by dowel pins. Sprocket to drive the cam chain is machhed on the center shaft. (Fig. 3-73A, B) 3.7 CRANKSHAFT, CONNECTING ROD, AND PISTONS 42 @ Left crankshaft @ 35 mm circlip @ 35mm side washer @ 1. ma% bearing outer ring @ 4 X 10 roller @ L. main bearing roller retoiner @ 5 mm sealing washer @ Left center crank weight @ 4 X 13 roller @ Center bearing roller retoiner @ Center crank shaft, @ R center crank outer ring @ Right center cronk weight @ Connecting rod @ 2.5X 10 roller @ Connecting rod roller retainer @ 6305 SHS bail bearing @ Right crankshaft Fig. 3-738. Cronkshaft complete sectional diagram The oil outlet passage in the upper crankcase is aligned to the oil annular groove in the cronk counterweight. Oil i s forced into the crankpin by centrifugal force to lubricate the connecting rod bearing. There is also a separate oil route to lubricate the main bearings. (Fig. 3-74) B. Disassembly 1. Drain oil from the crankcase. 2. Separate the cylinder head and cylinder. 3. Separate the left and right crankcase cover. 4. Separate the AC generator and clutch oil pump. 5. Disassemble the crankcase in accordance with section 3.6B. C. I @ @ Oil @ Center crank outer ring @ Crank weignt Connecting rod Fia. 3-74. Cronkshaft lubricatino nnqcnoe Inspection 1. Support the crankshaft on V blocks at both bearings and measure the amount of runout. (Fig. 3-75) Lett bearing Replace or repair if over Replace or repair if over @ Dial gauge Fig. 3-75. @ Crankshaft complete Measuring the shaft runout I 3. 43 ENGINE 2. The clearance in the bearing is measured b y fixing the crankshaft o n centers and moving the bearing in the axial and vertical direction. (Fig. 3-76, 3-77) Item Axial clearance Clearance normal to axis Standard Value Within 0.05 mm 10.0020 in) 0.01 2-0.02 mm (0.0005-0.0008 in) Serviceable Limit Replace it over 0.1 mm (0.0040 in) Replace if over 0.05 mm (0.0020 in) When the clearance in the axial direction becomes excessive, the crankshaft will move from side when engine is running and produce undesireable noises as well as causing uneven wear t o the cylinder, piston and the timing gear. @ Dial gauge Fia. 3-76. Checking the crankshaft for vertical clearance @ Main bearing outer ring @ Dial gauge @ V block 0 - Crankshaft Fig. 3-77. Checking the crankshaft for side clearance CONNECTING RODS Description The connecting rods a r e o f molybdenum steel ana have an H-shaped section; the roller bearings a t the crankshaft end. The crankshaft is polished after case hardening and mounts the roller without race. The roller (2.5X 10) is held b y the roller retainer made o f special aluminum alloy. Staggered rollers are used in order t o increase the l o a d capacity. (Fig. 3-78) @ Connecting rod Fig. 3-78. @ Roller @ Retainer I i B. Inspection 1. Measurement o f deflection a t the piston end of the connecting rod. (Fig. 3-79) Standard Value Deflection I I @ Max deflection Fig. 3-79. Checking deflection at the piston end of the connecting rod / Serviceable Limit Replace if over 3.0 mm (0.1 181 in1 3.7 CRANKSHAFT, CONNECUNG ROD, AND PISTONS 44 2. Measurement to determine if the connecting rod ends are correctly aligned and parallel is obtained by measuring the difference of inclination of points 50 mm (2.0 in) away from the center when a 100 mm (4.0 in1 bar with the same thickness as the piston pin diameter is inserted into the bore of the piston end and twisted to the right and left, and when the bar is rotated 90' and again twisted to the right and left. (Fig. 3-80) 3. PISTON A. Description The piston is made from select material, an aluminum casting. This material i s light and suitable for high speed, in addition to having good heat conducting property to dissipate the heat rapidly. Furthermore, the coefficient of heat expansion is small thus minimizing the warpage at elevated temperature and permitting a small piston to cylinder clearance design. The shape o f the piston is an elliptical taper. The head of the piston, compared to the skirt, is exposed to higher temperature and since the expansion is greater, it is taperingly smaller toward the top. The tapering of the piston also tends to lessen the piston slap when the throttle is lightly snapped without the engine being loaded. (Fig. 3-81) The piston employs a four step taper. The piston pin boss area is made thicker thereby resulting in greater expansion at high temperature. For this reason, the diameter of the piston skirt is made smaller in the direction of the piston pin so that at the high oprating temperature, the piston will expand into a true circular shape. The skirt is constantly provided with flexibility to assure that no deformation will result even from extended continuous driving. The piston pin i s offset 1 mm (0.04 in) from the piston centerline in the direction of the inlet side so that when the piston approaches the top dead center of the compression stroke, the side load from the cylinder moves from the right side to the left. With a "0" offset, the point will move to align with the top-deadcenter of the compression stroke. Q) Max deflection degree of Parallelism Fig. 3-80. Checking level of parallel at the piston end of the connecting rod L Q) Valve escape @ Piston ring grooves Fig. 3-81. Piston I i @ Piston pin hale I Fig. 3-82. Piston offset & Disassembly 1. Remove the piston pin clip and push out the piston pin. (Fig. 3-83) @ Piston pin clip @ Piston Fig. 3-83. Removing the piston pin 3. E N G I N E Remove the piston rings from the piston b y using a piston ring t o o l [special tool). If the t o o l is not available, the rings may b e removed by hand, spreading the rings a t the ring opening with both hands. During the process, the ring should not be twisted o r expanded more than necessary as it will cause the ring t o break. (Fig. 3-84) @ Piston ring @ Piston Fig. 3-84. Removing the piston ring C. Inspection 1. Before inspection, carbon adhering t o the piston head o r ring groove should b e removed, using care not t o scratch the piston. (Note) Sandpaper should not be used f o r removing carbon, use a carbon scraper. 2. Piston outside diameter I ltem . Fig. 3-85. .- .- ... .. .- .. Standard Value diameter Major diameter Measuring the piston outside diameter .. (Fig. 3-85) 3. Ring groove clearance when a new piston ring is fitted. . . (Fig. 3-86) -. -. 011ring 1 .-- - 0.010-0.045 mm 10.0004-0.0018 in1 , I .--- Replace if over 0.1 mm 10.004 in) @ Thi :kness gauge @ Piston ring @ Piston Fig. 3-86. Measuring the ring groove clearance 4. Piston pin hole Item Bore (Fig. 3-87) Standard Value Serviceable Limit 14.002- 14.008 mm (0.551 -0.552 in1 Replace if over 14.05 mm (0.5532 in) 5. For oversize pistons, there a r e three at intervals o f 0.25 mm (0.01 in). @ Cylinder gauge @ Piston Fig. 3-87. Measuring piston pin hole 3.7 CRANKSHAFT, CONNECTING ROD, AEID PISTONS @ Piston pin @ Piston Fig. 3-88. Assembling the piston 4. PISTON RINGS A. Construction The piston rings perform a vital function of forming a seal between the piston and cylinder, controlling the lubrication of the cylinder wall and dissipating the heat from the piston. This serves to develop greater power output. The rings are made o f special cast iron for strength, wear resistance, heat resistance and good heat conducting qualities. Rings are given parkerizing treatment for added strength. Top two rings are compression rings t o prevent gas leak, these two rings are made with a slight tapered surface where it contacts the cylinder wall t o expedite wearing-in, top ring outer surface is hard chrome plated for extra wear. The oil ring is grooved for oil scraping B. Inspection 1. When the piston ring has been removed, it should be fitted with the gap approximately 15 mm (0.6 in) from skirt of the cylinder at a right angle t o the center line. Measurement of the gap should be made with a thickness gauge. (Fig. 3-89) Top ring 0.15-0.4 mm (0.006-0.018 in) 0.15-0.4 mm Replace if over 0.8 rnm (0.0315 in) Replace if over 0.15-0.4 mm (0.006-0.01 6 in) Replace if over 0.8 mrn (0.0315 in) Fig. 3-89. Oil ring 2. Tension o f the piston ring i s measured with a tension measuring instrument. 0.52-0.78 kg Replace if under Measuring the piston ring gap 46 3. E N G I N E 47 Fig. 3-90A. Piston ring ITop) Fig.3-90C. Fig. 3-908. Piston ring (Second) Piston ring (Oil) 3. Piston ring dimensions. @ Outside Outside Outside Outside Outside Q @ Width Thickness Angle z: LY @ dia dia dia dia dia Outside Outside Outside Outside Outside dia dia dia dio dia (Standard) 0.25 (Oversize) 0.50 (Oversize) 0.75 loversize) 1 00 (Oversize) dia dia dia dia dio Width Thickness Angle 52.00 52.25 52 50 52.75 53.00 Serviceable L'mit (Standard) 0.25 (Oversize) 0.50 (Oversize) 0.75 (Oversize) 1.OO IOversize) Same as top ring 2.3-2.5 (0.091 -0.098 in) 1.175-1.19 10.046-0.047in) lo-1'30' 1.1 35 10.0447 in) [Standard) 0.25 (Oversize) 0.50 (Oversize) 0.75 (Oversize) 1.OO (Oversize) 2.475- 2.49 (0.097 1 None Mort None 25 50 75 100 (2.047 h) 12.057 in) (2.067 in) (2.077 in) 12.087 in) 2.3-2.5 10.091 -0.098 in) 1.1 65- 1.18 10.046-0.0464 in) 1.1 25 10.0443 in) 20'-50' Width Thickness Angle Outside Outside Outside Outside Outside C) Standard Value Item NO. (3 (Fig. 3-90A, B, - 0.098 in) 2.43 10.0957 in) 3.8 CAM CHAIN TENSIONER AND CAM CHAIN GUIDE ROlLER 48 C. Replacing the piston rings 1. When a piston ring is reassembled, it should be f i t t e d t o the cylinder. lnspection should be made to determine if the gap of each ring is between 0.15 mm (0.006 in1 and 0.4 mm (0.018 in). If the gaps are somewhat less, they should be dressed with a file. (Caution) (a) When a gap is dressed with a file, adjustment should be made perpendicular to the rings. (b) If the piston ring gap is too small, seizure between the ring and cylinder occurs due to thermal expansion; if the gap is too large, oil penetration or gas leakage occurs. 2. When piston ring is assembled on the piston, any interference between the ring and the groove may prevent smooth operation. It is necessary t o inspect for clearance, when new ring is fitted to the groove, by rotating the ring around the circumference. (Fig. 3-91) 3. Install the rings on the piston with the piston ring tool, the rings may also be installed manually. Install the bottom ring first. (Caution) (a1 Care should be exersized not t o install the rings upside down. The top side of the ring is marked near the ring opening with the manufacturers initials. (Fig. 3-92) (b) Worn or rings which has lost its tension should be replaced. 4. Space the piston ring gaps 120' apart. Aligning of the gaps will result in pressure leak. 3.8 @ P~stonring @ Piston Fig. 3-91. Inspection of the piston ring by rotating around the rino oroove @ Mark Fig. 3-92. Piston ring CAM CHAIN TENSIONER AND CAM CHALN GUIDE ROLLER Fig. 3-93. Cam chain tensione. 3. E N G I N E 1. CAM CHAIN TENSIONER A. Operation The cam chain tightener is used t o tighten the cam chain from the outer side with the cam chain guide roller in between. As shown in the figure, the tensioner push bar is automatically under compression by the cam chain tensioner spring and supports one end of the tightener. O n the other hand, the tensioner roller is applying pressure against the cam chain. When the tensioner set bolt i s loosened, the tensioner push bar automatically takes up the slack of the cam chain by applying force from the spring. (Fig. 3-93) 8. Disassembly 1. Separate the cylinder head and cylinder. 2. Tie a wire across the ends of the cam chain. 3. Remove the two 6 x 2 0 bolts mounting the cam chain guide roller and separate the cam chain tensioner from the crankcase. 4. The cam chain guide roller is coupled t o the cam chain tensioner and remove the cam chain guide roller pin and then separate the cam chain tensioner. (Fig. 3-94) 5. When the 5 mm thin nut is loosened and the tensioner set bolt is removed, the tensioner push bar coupled t o the cylinder head is separated together with the tensioner spring. (Fig. 3-95) @ Cam chain guide roller @ Cam chain Fig. 3-94. Cam chain tensioner C. Inspection 1. Check the cam chain tensioner for any damage o r wear. Item Tensioner spring free length Tension I I Standard Value 83 mm (3.268 in1 41 mm/0.55-0.65kg (1.614in/1.21-1.43 1 I Serviceable Limit Replace i f under 80 mm (3.1 496 in1 - Ibsl D. Reassembly 1. Perform the assembly in the reverse order o f @ Tensloner set bolt @ Tensloner push bar @ Tensioner spring Fig. 3-95. Assembling the tensioner push bar a> Lock nut @ Tensioner set bolt Fig. 3-96. Adjusting the cam chain I disassembly. a. Replace any worn o r damaged guide or tensioner roller. 3.9 TRANSMISSION 3.9 TRANSMISSION A. Description The transmission receives the rotary power from the crankshaft and through a series of gears, changes it to the desired speed and then transmits it t o the drive sprocket t o drive the rear wheel. All the gears are fully constant meshed, assuring smooth gear change. (Fig. 3-97) @ 6304 HS ball bearing @ Transmission main shoft @ Main shaft top gear @ 20 mrn thrust washer A @ 20 mrn cir-clip @ Ball bearing set ring A @ 8 X 152 stud @ 1 0 X 14 knock pin @ Main shaft shifting gear Main shaft second gear @ 15rnm bearing bush A @ Knock pin @ 8 X 2 5 X 8 oil seal @ 16 mrn bearing bush B Knock pin @ Counter shaft low gear @ Counter shaft second gear @ 20 mm cir-clip @ 20 rnm thrust washer A Counter shaft fourth gear @ Counter shaft third gear @ Counter shaft top gear @ 2 0 X 5 2 X 9 TC-type oil seal Drive sprocket l16T) @ Drive sprocket fixing plate @ 6 X 10 hex. bolt @ 1 0 X 14 knock pin Transmission counter shoft Fig. 3-97. Transmission @ @ @ @ @ 1. OPERATION When the clutch is engaged, the power from the crankshaft is transmitted through the clutch assembly t o drive the transmission main shaft. During the shifting of the transmission gears, the clutch is disengaged t o stop the rotation of the main shaft. The position of the gears will be described in reference to the neutral gear. Neutral : (Fig. 3-98) When the transmission is in neutral, the gears in the transmission are arranged so that there is no power transmitted from the transmission main shaft t o the counter shaft. The fixed main shaft low gear @ is meshed with the free rotating counter shaft low gear @, free rotating main shaft Fig. 3-98. Neutral 3. 57 ENGINE top gear @ is meshed with the sliding counter shaft top gear @, sliding main shaft third-fourth gears Q are meshed with the free rotating counter shaft. thirdfourth gears @ @ and the free rotating main shaft second gear @ is meshed with the splined counter shaft second gear @. Low Fig. 3-99. Low gear : (Fig. 3-99) When the gear is shifted t o low, the sliding counter shaft top gear @ is moved by the shift fork t o engage with the free rotating counter shaft low gear @. The power from the transmission main shaft @ i s transmitted through the fixed main shaft low gear t o the counter shaft low gear, across t o the counter shaft top gear and then to the drive sprockt @ mounted on the end of the counter shaft. Second : (Fig. 3-100) When the gear is shifted t o second, the sliding main shaft third-fourth gear Q is moved by the shifi fork t o engage with the free rotating main shaft second gear @. The power from the transmission main shaft @ is transmitted through the main shaft third-fourth gear t o the main shaft second gear which drives the counter shaft second gear @ and hence the drive sprocket @ mounted on the end of the counter shoft. Fig. 3-100. Second gear Third : (Fig. 3-101) When the gear is shifted t o third, the counter shaft top gear @ is moved by the shift fork t o engage with the counter shaft third gear @. The power from the transmission main shaft is transmitted throught the main shaft third-fourth gear t o the counter shaft third gear, across t o the counter shaft top gear @ and t o drive the drive sprocket Q mounted on the end of the counter shaft. Fourth : (Fig. 3-102) Fig. 3-101. Third gear When the gear i s shifted t o fourth gear, the sliding counter shaft second gear @ is moved t o become engaged with the free rotating counter shaft fourth gear @. The power from the transmission main shaft is transmitted through the main shaft thirdfourth gear @ t o the counter shaft fourth gear @, across t o the counter shaft second gear @ and then t o the drive sprocket @ at the end of the counter shaft. Top : (Fig. 3-103) When the gear is shifted t o top gear, the sliding main shaft third-fourth gear @ is moved by the shift fork t o become engaged with the free rorating main shaft top gear @. Fig. 3-102. Fourth gear The power from the transmission main shaft is transmitted t o the main shaft third-fourth gear @, over t o the main shaft top gear @, across t o the counter shaft top gear @ and then t o the drive sprocket @ at the end of the counter shaft. 3.9 TRANSMISSION 52 B. Disassembly 1. Disassemble the cylinder head and cylinder. 2. Separate the crankcase. C. Inspection 1. Main shaft t o ,main shaft gear clearance. ltem Second gear 115)) Top gear (20$ I 1 / / Standard Value 0.016-0.045 mm 10.0006-0.0018 in) 0.01 1-0.045 mm (0.0004-0.0018 in) / 1 Serviceable Limit Replace i f over 0.1 mm (0.004 in) Replace i f over 0.1 mm (0.004 in) 2. Counter shaft to counter shaft gear clearance. ltem I Standard Value ~ h l r d 0 009-0.025 mm 0004-0.0010 in) Fourth geprl 10 0 016-0 045 mm Low gear / 10 0006-0 0018 1n1 3. Bear~ngclearance Item Ax~al clearance Radlal clearance , I Fig. 3-103. Top gear Serviceable Limit Replace ~f over mm 10 004 1n1 Replace ~f over 0 1 mrn I0 004 In) -L 1 -1 I (Fig. 3-104) Standard Value Serv~ceable L~mlt ~ c $ w o v e r 10 002 1n1 1 0 L m ~ ( 00 0 4 0 01 - 0 025 mm Replace ~f over 10 0004-0 001 0 fnl 0 05 mm 10 002 in1 , W ~ t h ~0n05 mm / -' -@ Dial gauge 4. Shift drum groove. @ Bearing @ V block Fig. 3-104. Meosuring clearance of the bearing Fig, 3-105. Meosuring the shift drum groove (Fig. 3-105) Standard value : 6.1 -6.2 mm (0.240-0.244 Serviceable limit : 6.4 mm 10.256 in) in! D. Reassembly 1. Assemble the transmission gears in the reverse order of removal. 2. After assembly, all components should be checked to assure that the operation is smooth without any binding. 3. Inspect the mating surfaces of the crankcase for any scratches or damage which will be a source of oil leak. 3. E N G I N E 3.1 0 GEAR SHIFT A. Operation 1 @ Shift drum stopper @ Gear shift drum @ Gear shift arm spring @ Gear,shift return spring @ Gear shift spindle comp. I The gear shift fork is moved linearly by the rotary movement of the gear shift drum. When the gear shift pedal is depressed, the gear shift spindle, through the gear shift arm, causes the shift drum t o move either in the clockwise o r counter clockwise direction, depending upon whether the forward or rear of the pedal is depressed. The shift forks are fitted over the shift drum and guided in its linear movement by the cam groove on the surface o f the shift drum into which the fork guide pins are inserted. Rotation of the drum shifts the forks t o the right or left which in turn performs the gear shifting. A gear shift return its normal position after each gear change stroke. (Fig. 3-106) 8. Disassembly 1. Disassemble the transmission in accordance with section 3.9. B. 2. Pull out the gear shift guide pin clips and guide pins. (Fig. 3-107) @ Shift fork guide pin clips @ Gear I shift forks Fig. 3-107. Removina the shift fork auide oins 3'. Remove the neutral switch rotor and stator from the left end of the shift drum. 4. Unscrew 6 x 2 0 hex, bolt @ and remove the shift drum stopper (Fig. 3-108) @ and stopper arm plate @ @ Shift drum stopper @ Stopper arm plate @ 6 x 2 0 hex bolt 5. Draw out the gear shift drum. 6. The gear shift spindle and return spring can be removed by removing the set ring from the opposite end of the gear shift spindle. (Fig. 3-109) @ Gear shift spindle @ 12 mm set ring Fig. 3-109. Removing the gear shift spindle 3.70 GEAR SHIFT 3.7 7 KICK STARTER 54 C. Inspection 1. lnspect the gear shift spindle, gear shift arm and gear shift forks for twist or bend. 2. Inspect the gear shift drum and guide pin for excessive wear. 3. Check the springs for breakage and proper tension. D. Reassembly 1. Insert the gear shift drum at the right side of the upper crankcase and assemble the gear shift fork in the crankcase. (Fig. 3-1 10, 3-1 11) 2. Assemble the shift fork with the gear shift fork guide pins and guide pin clips. 3. Assemble the neutral switch rotor and the stator. 4. Assemble the shift drum stopper; this completes upper case assembly. I I @ Gear shift fork guide pin (?) Gear shift fork guide pin clip @ Left gear shift fork Right I gear shift fork @ Center gear shift fork @ @ Gear shift drum. Fig. 3-1 10. Component parts of gear shift drum. 5. Assemble the gear shift return spring in the lower crankcase. 6. The gear shift spindle should be inserted together with the return spring from the right side o f the lower crankcase. The gear shift spindle side stopper and oil seal should be inserted at the left end of the shift spindle and then install the set ring. 7. Assemble the crankshaft with transmission gears in the upper case and tighten the lower crankcase. 8. Complete the assembly in accordance with section 3.8. 3.1 1 KlCK STARTER Gear shift fork @ Gear shift drum Fig. 3-1 1 1 . Assembling the gear shift fork @ 25 mm cir-clip @ Friction spring @ Kick starter pinion @ Kick starter washer spring @ 4 X 15 knock pin Fig. 3-1 12A. Kick starter assembly Kick starter spindle @ Kick starter 3. ENGINE A. Construction The kick starter pinion engages with the transmission l o w gear and b y utilizing the transmiss~~n gears kicking is made easy and does not require much force. When the kick starter shaft is rotated b y the kicking action the serrated kick starter ratchet flange is rotated simultaneously and the pawl o f the kick starter ratchet flange slides d o w n from the kick starter guide and is pushed against the kick starter pinion groove b y the pawl spring. Power is transferred from the kick starter pinion t o the countershaft l o w gear. @ Kick starter washer @ Kick starter spring W h e n the kick starter is not depressed o r the kick starter pedal is released after kicking, the kick starter ratchet flange is pushed back by the kick starter spring. The pawl rests o n the kick starter ratchet guide and the kick starter pinion is freed. (Fig. 3-1 l 2 ~ B) , @ Kick starter spindle Fig. 3-1 12s.. Disassembling the kick starter B. Disassembly 1. Separate upper and lower crankcase i n accordance with section 3.10. B. 2. Take out the kick starter shaft. 3. Remove the main shaft, countershaft and gear shift drum. C. Inspection Check the ratchet and the kick starter pinion ratchet f o r excessive wear and replace i f excessive wear exists. D. Reassembly Reassemble the kick starter i n the reverse order of disassembly. Setting specification (CB175, CL175) Model C8 175 CL 175 Carburetor type PW 20 PW 22 Setting mark Main bore Main jet Air jet CB-B 20 mm 10.787 in1 # 95 #lo0 B 22 mm 10.867 in1 # 98 # 100 2.64 X 3.64 3", 2.535gl-3 stage #2.0 I%*% #35 (0.7 X 2 X 3) 1.74 0.84 P=8.0 mm 19.5 mm 10.768 in1 2.64 X 3.64 4', 2.5354-3 stage #3.0 (Width 1.2 depth 0.51 Air bleed Needle jet Jet needle Cut-away (throttle valve) Air screw Slow jet Valve seat Pilot outlet Fuel level NtN #38-#40 (0.64 X 2 X 2) 2.04 1.04 P=8.5 rnml 28.0 mm 11.1 in) 3.72 CARBURETOR 3.1 2 CARBURETOR (CB175, CL175) A. CONSTRUCTION The CB175 or CL175 is equipped with a twin variable venturi carburetors operated synchronously by a single cable from the throttle grip branching t o the two throttle valves. The choke valves are connected by a linkage. Each cylinder is equipped with an individual carburetor t o provide maximum performance. The operation of the engine creates a vacuum within the cylinder and this draws the outside air into the cylinder after having been passed through the air cleaner where the air is cleaned, through the carburetor, where the proper amount of fuel has been mixed to form a combustible mixture and finally enters the cylinder where it is ignited t o produce the power necessary to perform work. 1. FUEL SYSTEM As the air enters the carburetor, it passes under the throttle valve where vacuum pressure is produced due to the restriction caused by the throttle valve extending into the main air passageway. The fuel discharge outlet is located in this so-called venturi area so that the vacuum pressure can draw out the fuel. This carburetor incorporates both the main and a slow system. Fig. 3-113. Sectional view of carburetor ICB1751 3. E N G I N E Fig. 3-114. Sectional view of carburetor lCL175) A. Main system (Fig. 3-1 13, 3-1 14) The fuel passes through the main iet @ and enters the needle iet holder @ where it mixes with the bleed air entering from the bleed hole located around the needle iet holder @. The fuel air mixture passes by the opening between the needle jet @ and iet needle @ and is discharged from below the throttle valve @. It is here that the mixture is combined with the main air and after being atomized, is taken into the engine. Fig. 3-1 15. @ Slow iet B. Slow system (Fig. 3-1 15) The air which enters from the inlet passes through the outside of the air screw where it is metered and enters the slow iet bleed hole. it mixes with the fuel which enters the slow jet @ t o produce a full spray that is discharged from the pilot outlet at a point under the throttle valve. This mixes with the air from the air inlet t o form a combustible mixture before being taken into the engine. 2. FLOAT CHAMBER (Fig. 3-116) The carburetor must provide a proper mixture o f fuel at different throttle openings and engine speeds; in order t o accomplish this, the fuel level in the carburetor must be maintained constant. The float chamber functions t o serve this purpose. The fuel from the tank enters the float chamber through the fuel inlet passage, between the float valve seat @ and float valve @ and fills the chamber t o the level where the float @ rises t o shut off the flow o f the fuel by seating the float valve against the valve seat through the action of the float arm @. As the fuel is consumed, the fuel level in the float chamber, drops the float will follow the level, and the fuel will start t o enter the chamber between the opening o f the float valve and valve seat to maintain a constant fuel level. 3.73 CARBURETOR 58 A spring is incorporated in the head o f the float valve which comes in contact with the float arm. The purpose o f this spring is t o prevent the float valve from oscillating so that a constant fuel level can be maintained even when riding over rough or bad roads. It further serves t o prevent any shock between the float valve and seat, thereby reducing the amount of wear t o these parts. Overflow pipe When riding on a steep grade or when any foreign substance becomes lodge in the float valve, it causes the fuel t o overflow from the needle iet or the slow jet, and enters the engine causing the engine oil t o become diluted. In order t o prevent such a condition, an overflow pipe has been incorporated in the float chamber. At normal condition, the pipe opening is above the fuel level and it serves no purpose, but when the overflow condition exists and the fuel level rises, the fuel will drain out o f the overflow pipe to the outside rather-than into the engine. 3. CHOKE I @ Floot chamber washer @ Floot valve @ Float valve seat @ Floot arm @ Float Fig. 3-1 16. Sectional view of float chamber. (Fig. 3-1 17) For starting in cold weather, a rich fuel mixture is momentarily required; t o serve this purpose, a choke valve @ is used in the carburetor. A relief valve @ is included in the choke valve and is held closed by a spring. By raising the choke lever fully, the choke valve c l ~ s e sand the air entering from the air inlet becomes restricted. When the starting motor is engaged with the throttle lever opened approximately 1/4, the fuel will be drawn out of the pilot outlet and the needle jet by the vaduum pressure. At the same time, the vacuum pressure will cause-the relief valve t o open by the proper amount t o provide a n ideal fuel mixture t o effect and engine start. As the engine starts, the vacuum pressure becomes greater and the relief valve is opened further t o provide the proper fuel mixture t o warm up the engine. In this manner, the throttle valve movement causes the relief valve t o operate and, therefore, the operation o f the choke valve is not required t o warm up the engine. The choke valve is opened after the engine warms up. Fig. 3-1 17. Choke valve. FUNCTION OF THE MAIN COMPONENTS The main components of the carburetor functions in the following manner. 1. MAlN JET (Fig. 3-1 18) The function of the main jet is t o control the fuel discharge and t o provide the proper fuel air mixture at the higher range of throttle opening (driving at maximum speed). However, the main jet will also have a varying degree o f effect in the vicinity o f 1/2 throttle opening. The main jets are numbered, so that the larger the number. bigger the opening and consequentty a richer fuel-air mixture. Fig. 3-1 18. Main jet 1 3. E N G I N E 59 2. AIR JET At full throttle opening, the fuel-air mixture has a tendency t o become rich, and in order t o prevent this condition, a bleed air is added t o the fuel through the needle jet holder. The purpose o f the air jet is t o meter the amount of this air ; the larger the air jet, more air will be added t o the fuel mixture and a leaner fuel mixture is provided. Also, by mixing the air with the fuel, better atomization will be assured. 3. NEEDLE JET Fig. 3-1 19. Needle iel 4. JET NEEDLE Fig. 3-120. Jet needle (Fig. 3-119) At full or intermediate throttle opening, the needle jet will regulate the fuel which had been metered by the main iet. This control is accomplished together with the jet needle which will be described in the following paragraph. The hole of needle jet is made very accurately for precise control. (Fig. 3-120) The jet needle together with the needle jet described in the previous paragraph, meters the discharge o f thefuel mixture in the l / 4 t o 3/4 throttle range. The long tapered needle is suspended within the needle jet opening. The jet needle moves up and down with the throttle t o control the fuel mixture proportionally t o the throttle opening. There are three grooves on the head of the jet needle by resetting the set clip toward the lower aroove, a richer fuel mixture will be provided. - 5. THROTTLE VALVE Fig. 3-121. Throttle valve (Fig. 3-121) The throttle valve regulates the amount of fuel air mixture taken into the engine t o control the output and spqed o f the engine. In addition, it serves a very important function in that it controls the fuel mixture. There is a cutaway o n the throttle valve at the air inlet side which affects the vacuum pressure that controls the function of the needle jet. The use o f the throttle valve with different size cutaway will control the discharge rate o f the fuel, which affects the fuel-air ratio. The larger throttle valve cutaway number provides leaner mixture, however, this is only effective within the lower range of the throttle opening and has no effect above l / 2 throttle opening. There is also a throttle stop screw which sets the idling speed. Turning this screw IN will raise the idling speed, and lowers the speed when the screw is turned OUT. 6. SLOW JET (Fig. 3-122) The slow jet controls the fuel at slow speed and at idling by regulating the air entering from the air bleed t o produce a fuel-air mixture which assists in the atomization of the fuel. The slow jet, like the main jet, provides a richer fuel mixture when a jet o f larger number is used. @) Slow jet Fig. 3-122. Slow jet 3.73 CARBURETOR 7. AIR SCREW (Fig. 3-123) The air screw regulates the air entering the slow system by controlling the pilot hole. Turning the screw IN will richen the mixture and turning the screw OUT will lean the mixture. 60 I 8. FUNCTIONAL R A N G E O F THE RESPECTIVE COMPONENTS In summarizing the description stated above, the functional range of the respective components are as follows : Air screw: Throttle valve cutaway: Jet needle : Main jet : from full close t o 118 throttle opening Fig, 3-123. Air screw 1/8 t o 114 throttle opening 114 to 314 throttle opening 314 to full throttle opening ADJUSTMENT 1. H I G H SPEED ADJUSTMENT During driving, if the speed increases when the choke valve is closed slightly, it is an indication that the fuel mixture is lean. In which case, replace the main jet progressively with the next larger size until properly adjusted. The main jet sizes above # I 0 0 are #105, #I10 and # I 1 5 and for sizes below # I 0 0 are #98, #95 and #92. In the opposite case, if the speed should fall off when the choke valve is closed, the main jet size is proper, or else, it may be t o o large. In which case, follow the procedure below t o make the determination. @ Throttle stop screw @ Air screw Fig. 3-124. Adjusting cofburetor A. P r o p e r l y set When, after replacing the main jet with one of a smaller size and if it is found t o cause a drop in speed, and an increase in speed when the choke is slightly closed, it is an indication that the main jet is too small. The replaced jet can be considered t o be o f the proper size. B. M a i n jet t o o l a r g e When the jet is too large, progressively replace the iet with one of a smaller size until the condition in paragraph A above occurs, and make the adjustment accordingly. 2. INTERMEDIATE SPEED ADJUSTMENT (Fig. 3-1 25) The adjustment within 118 to 3/4 throttle opening is made by the changing the position o f the clip o n the iet needle groove and the replacement of the throttle valve cutaway. However, the throttle valve cutaway will affect the fuel mixture between idling and 114 throttle opening. In the intermediate speed range, it is recommended that the iet needle b e adjusted within the range of good acceleration as this will prove t o give better fuel economy. ~ l valve ~ Fig. 3-125 @ ~ Float t arm @ Float gauge @ Float 3. E N G I N E A. Jet needle (1) When excessive black smoke is emitted from the exhaust during intermediate speed, it is an indication of rich fuel mixture, therefore, lower the iet needle by one groove. (21 During driving, if the engine misses or bucks, raise the iet needle one groove. B. Cutaway of the throttle valve The throttle valve with a larger number stamped on the cutaway will give a leaner mixture. Throttle valve will affect the performance of the slow speed as well as the intermediate speed, therefore, the range affected shbuld be considered when making the adjustment. 3. SLOW SPEED ADJUSTMENT The fuel mixture adjustment between idling and 1/8 throttle opening is accomplished with the air screw and the cutaway of the throttle valve. A. Air screw The mixture adiustment at idle is made by the air screw. Turning the screw clockwise will give a rich mixture and turning in the opposite direction will lean the mixture. Not only is the idling screw used to make the idling adjustment but it also should take into consideration the mixture condition at the point where the throttle starts to open so that there is a smooth transition from the idling speed to the start of throttle opening speed. B. Adjusting with the throttle cutaway As a point 1/8 throttle opening, the air screw may no longer be effective in adjusting the fuel mixture In such a case, replace the cutaway. If the mixture is too rich, replace the cutaway with one of a larger number and if the mixture is too lean, replace with one of a smaller cutaway number. C. ldle adjustment (Fig. 3-124) ldle adjustment is made by the use of' both the throttle stop screw and the air screw by the following procedure. (1) Use the throttle stop screw to set the engine to the proper speed. (2) Manipulate the air screw back and forth slowly to obtain the point of maximum speed. (3) Reset the throttle stop screw to bring the speed back to the normal. (41 In this position, recheck the air screw to assure that the setting is correct. (5) After completing the idle adiustment, check the engine response by snapping and accelerating the throttle. Perform this check between 1/8 to 1/4 throttle opening. 4. FUEL LEVEL ADJUSTMENT (Fig. 3-125) The float adjusting procedure The float level is specified by the height of the float " h" shown in figure 3-125. CB175 : h= 19.5 mm (0.768in) CL175 : h=28.0 mm (l.linl is described below in conjunction with figure 3-125. Invert the carburetor, in this condition, the weight of the float has caused the float arm to bear against the float valve and the spring is compressed into the valve. This is not the normal fuel level position. b. Next, set the carburetor as shown in the figure with the float arm pin toward the top, tilt the carburetor so that the float is on the bottom with the float arm in the position so that it is just about to separate from the end of the float valve and set in this position. (the arm will separate from the end of the valve when the carburetor is raised approximately 70°, therefore, about 10" from fhis point is sufficient, i.e., where the arm is not compressing the valve end). c. In this position, measure the distance the bottom of the float is from the body flange area with the gauge, this is the height " h". The tolerance is 1 Am, the float may be depressed 1 mm or there may be a clearance of 1 mm between the gauge and the float. This much to lerance will not adver sely affect the operation. If the float is positioned in excess of this amount, make the adjustment by bending the tip of the float arm. There is a spring incorporated in the end of the float valve which will permit the end of the float valve to submerge and will give and erroneous reading, therefore, exercise care when determining the point of contact. Improper measurement and adjustment will not give the proper fuel level. a, 3. ENGINE C Engine assembly diagram (Fig. 3-1 26) ENGINE 62 3. E N G I N E 63 Engine assembly diagram (Fig. 3-127) 3.7 ENGINE REMOVAL AND INSTALLATION The extensive use of aluminum alloy gives a good weight to power ratio which attributes t o high performance. It also provides good engine cooling. 64 @ 8kX20 hex. bolt OHC driven by a lightweight chain makes possible higher engine speed, greater power output and quiet operation. Long life of the engine component and trouble free maintenance is assured by the empioymertt of dual oil filtering in the pressure lubrication system. B. Engine removal (CB 125 and CL 125) 1. Shut off the fuel cock at the fuel tank. 2. Remove the muffler by unscrewing the four 6 mm nuts at the cylinder head and the two 8 mm bolts. TO remove the muffler @ (CL 1251, unscrew the four 6 mm nuts at the cylinder head, exhaust pipe setting bolt @ and 8 x 2 0 bolt @ at the rear of the seat. (Fig. 3-128) @ 6 X 10 Ihex. bolts Q 5 X 16 cros screw Fig. 3-129. Removing the air cleaner @ Air cleaner (Note) Remove the exhaust pipe protector t o facilitate the removal of the exhaust pipe setting bolt. 3. Remove the air filter covers. Unscrew the two 6 X 12 bolts (5) and I X 15 cross screw @ at the air cleaner connecting tube and remove the air filter @. (Fig. 3-129) 4. Disconnect the high tension terminal from the spark plug and all electri:al leads. (Fig. 3-130) Fig. 3-130. Disconnecting the electrical leads Fig. 3-131. Disconnecting the clutch cable 3. 65 ENGINE 5. Remove the drive chain cover and disconnect the clutch cable end @ from the clutch lifter thread (Fig. 3-131) @. 6. Disconnect the chain ioint clip @ and remove the drive chain 0. (Fig. 0 3-132) 7. Remove the 6mm nuts @ Fig. 3-132. Removing the drive chain Fig. 3-133. Removing the carburetors mountind the carburetors t o the cylinder head. (Fig. 3-133) 8. Remove the four 8 x 2 5 bolts at the underside of the crankcase and remove the step bar. 9. Unscrew the four engine mounting nuts. Place a support block under the engine t o prevent dropping, push out the mounting bolts and then the engine will b e freed from the frame. 2. The engine installation can b e made easier b y temporarily hanging the engine on the frame b y the use of a T-handle cross screw driver @ followed by the installation of the engine mounting bolts. (Fig. 3 - 1 34) (Note) When reconnecting the drive chain, the joint clip should be installed with the opening facing opposite t o the direction o f the n o r n a l chain movement. (Fig. 3-135) 3. Adjust the chain tension so that there will be 1 t o 2 cm 10.40-0.80 in1 slcck in the chain. -- @ T-handle cross screw driver Fig. 3-134. Installing the engine i - .- - - - - - ..- - - DIRECTION OF ROTATION @ Joint clip Fig. 3-135. Joint clip instollation - I I 3.2 2 CYLINDER HEAD AND CYLINDER 66 CYLINDER HEAD AND CYLINDER . CYLINDER HEAD, COVER AND BREATHER r. Construction The cylinder head is a cast aluminum twin head construction of a semi-spherical combustion chamber with a squish area for better combustion efficiency. (Fig. 3-136) The single piece overhead camshaft, rocker arms and valve mechanisms are all incorporated in the valve chamber above the combustion chamber. Cylinder head cover incorporates a breather passage for dissipating the pressure build up. Fig. 3-136. Cylinder head Fig. 3-137. Removing the cylinder head cover. B. Disassembly 1. Drain oil from the engine. 2. Remove th,e 8 mm blind nut and five 8 mm hex. nuts, and then remove rhe cylinder head cover, (Fig. 3-137) 3. Remove the left and right cylinder head side covers by unscrewing the long bolt from the left side '4. Rotate the crankshaft so that the cam chain joint is toward the top of the cam sprocket and then remove the cam sprocket mouuting bolts. 5. Attach a wire @ to both ends of the chain @ and then disconnect the cam chain, this will simplify the reassembly task later. (Fig. 3-138) 6. Separate the cylinder head from the cylinder. C. inspection 1. Disassemble and clean all the parts before inspection. Carbon, should be removed with care, using a carbon scraper to prevent damaging the head. (Fig. 3-139) 2. Refer to section 3.2 C on page 21. 3. lnspect the combustion chamber, inlet and exhaust ports for cracks. 4. lnspect the valve guide and valve stem. Check the valve guide diameter at the top, center and bottom in both the X and Y axes, using a precision cylinder gauge. 'Check the valve stem with micrometer. @ Wire @ Cam chain Fig. 3-138. Attachirg the wire to the cam chain Fig. 3-139. Scraping carbon from combustion chamber 3. E N G I N E Standard Value item 5.48-5.49 mm Outside diameter 10,2158-0.2162 in) Inlet valve Within 0.02 mm Contact face runout* (0.0008 in) 5.5-5.515 mm Inside diameter 10.2165-0.2171 in) 10.055- 10.065 mm Inlet valve guide Outside diameter 10.3959-0.3963 in) 0.04-0.065 mm Interference ' (0.0016-0.0026 in) 0 01-0.035 mm Inlet valve clearance (d.0004-0.0014 in) 5.46-5.47 mm Outside diameter (0.2150-0.2154 in) Exhaust valve Within 0.02 mm Contact face runout 10.0008 in) 5.5-5.51 5 mm Inside diameter ' (0.2165-0.21 71 in) 10.055 10.065 mm Exhaust valve guide Outside diameter (0.3959-0.3963 in) 1 1 . ./ 1 - 3-0.055 mm Serviceable Limit Replace if under 5.46 mm 10.215 in) Replace if over 5.555 mm 10.21 9 in) Replace if over 0.08 mm 10.028 in) Replace if under 5.44 mm (0.214 in) Replace if over 5.555 mm 10.219 in) I Replace i f o If the valve guide is beAyond serviceable limit, i t may be repaired by using a reamer (Tool N o . 07008-00101) and replacing the valve with one of an oversize. 5. When replacement o f the valve guide becomes necessary, remove and replace with an oversize guide; use the valve guide remover (Tool No. 07942-3290100) and the valve guide driver (Tool N o . 07942-3290200) for replacement operation. After installing the valve guide, use a reamer t o obtain the proper valve clearance. D. Reassembly 1. Reassemble the cylinder head in the reverse order of disassembly. @J " 0 " mark Fig. 3-140. installing the cam sprocket (Note) (a1 Before installing the cam chain, the valve must b e timed in reference t o the position o f the crankshaft. To d o this, first, position the crankshaft so that the knock pin at the tapered shaft end is on the cylinder centerline and toward the cylinder head. Then align the "0" mark stamped on the cam sprocket t o the index mark on the cylinder head (both inlet and exhaust valve should b e closed, if not, rotate the cam 180°.) In this position, connect the cam drive chain. (Fig. 3-140) (bl Check the condition o f the gaskets. It is recommended that a new gaskets b e used throughout, especially the head gasket. (Fig. 3-141) (c) If the cam chain tensioner push r o d is not screwed in completely, the cam chain cannot be connected. @J Cylinder head cover gasket Fig. 3-141. 3.2 CYLINDER HEAD AND CYLINDER Tighten the cylinder head cover nuts uniformly in the sequencq shown : (Fig. 3-142) Torque : 180-230 kg. cm (13.0-1 6.7 ft. Ibs) Insert the bolt in th rough the center bolt hole on the left side cover, assemble and tighten the right side cover. Fig. 3-142. Torquing sequence of cylinder head Fig. 3-1 43. Comshofl 2. CAMSHAFT A. Construction A single piece camshaft contains both inlet and exhaust cams together with the sprocket which is mounted at the left end. (Fig. 3-143, 144) The cam sprocket is driven by the crankshaft at the speed. The cam is designed with a long gradual slope t o prevent abrupt rise and drop of the valve, thus assuring a quieter valve operation. @ Camshaft @ Cylinder head @ Cylinder head right side cover Fig. 3-144. Oil passage diagram @ Cylinder head left side cover 68 3. E N G I N E 69 B. Disassembly 1. Remove the cylinder head in accordance with Section 3.2.1 B. 2. Remove the tappet adjusting hole caps and loosen the tappet adjusting screws. 3. Remove the 5 mm hex, bolt holding the rocker arm shaft stopper and pull out the rocker arm shafts, and the rocker arms can be removed from the cylinder head. 4. Remove the camshaft from the cylinder head by sliding out the left side. C. Inspection 1. Valve timing (Fig. 3-145) 2. Check the cam for excessive wear or scoring. 3. Camshaft (Fig. 3-146, 3-147) C G base i llN circle Cam height @ @ @ @ Inlet & l i e opens: 5'BTDC Inlet valve closes: 30°ABDC Exhaust valve opens. S0BBDC Exhaust valve closes: 35"ATDC Serviceable Limit Standard Value 19.953- 19.964 mm Replace if under (0.7857-0.7861 in) 19.93mm 10.7846inl 32.927-32.94 mm Replace if under 11.2963- 1.2968 in) 32.907mm11.2955inl 21.0 mm (0.8268 in1 26.1 77mmi1.0306inl 25.740mmi0.0 134inl 4. Cam sprocket root diameter Standard value tS 59.87-59.99 mm 12.358-2.364 in) D. Reassembly 1. Screw ddt the tappet adjusting screw and assemble the camshaft into the cylinder head in the reverse order of disassembly. 2. Adjust the tappet clearance to 0.04 to 0.06 mm (0.015 to 0.023 in) with a cold engine. 3. ROCKER ARM A. Construction @ Dial gauge @ Camshaft Fig. 3-146. Measuring the camshaft The function of the rocker arm is t o transpose the rotary motion of the camshaft to a recprocating motion for actuating the valve. The rocker arm is made rigid t o prevent deflection and the end which contacts the cam is finished smooth after surface hardening t o minimize wear. The end which operates the valve is provided with a tappet adjusting screw that contacts the valve. 8. Disassembly 1. Disassemble the cylinder head in accordance with Section 3.2.1 B. 2. Remove the tappet adjusting screws. Fig. 3-147. Camshaft dimensions 3. Rotate the camshaft so that the rocker arms are resting on the base circle of the cam (this can be set by aligning the "0"mark stamped on the cam sprocket t o the index mark on the cylinder head left cover flange). 3.2 CYLINDER HEAD AND CYLINDER 70 4. Remove the bolt holding the rocker arm shaft stopper @ and pull out the rocker arm shaft @, the rocker arm can then be removed. (Fig. 3-148) To facilitate the removal, use the snap ring plier. (Fig. 3-149) C. Inspection 1. Clean all parts, especially make sure that the oil holes are clean. 2. Inspect the rocker arm cam contact surface and repair or replace if there is, scoring or excessive wear. Rocker arm @ Rocker arm shaft stopper Q 5 X 10 hex. bolt @ Rocker arm shaft Fia. 3-148. Removing the rocker arm shaft Rocker arm shaft - Item I Standard Value 9.972-9.987 mm Outside dia (0.3926-0.3933 in) 1 0.013-0.043 mm CIeorance (0.0005-0.0017 in) 1 1 1 I Serviceable Limit Replace if under ( Z m m (0.3934 i n c / Replace if over 1 0.08 mm (0.0031 in1 / @ Rocker arm shaft @ Plier Removing the rocker arm shaft Fig. 3-149. Check for proper tappet clearance, both inlet and exhaust should be 0.05 mm 10.002 in], too small a clearance will cause the valves to remain partly open, causing compression leak and results in hard starting. D. Reassembly Reassemble the valve rocker arm in the reverse order of disassembly. 4. VALVE A. Construction Refer to section 3.2.5 on page 27. 8. Disassembly 1, Remove the cylinder head. Refer t o Section 3.2.1 A. 2. Disassemble the rocker arm; and camshaft from the cylinder head. Refer to Section 3.2.3. B and 3.2.2. B. 3, Compress the valve spring with the valve lifter (Tool No. 07957-32900001 and after removing the valve cotter, valve spring and retainer, the valve can be removed. (Fig. 3-151) @ Cam shaft Q Valve rocker arm @ Piston @ Crankshaft @ Cam chain guide roller @ Cam chain tensioner roller @ Cam chain tensioner Fig. 3-150. Valve mechanism. 3. E N G I N E 77 -- -- - 1 C. Inspection 1 Exhaust valve (Fig. 3-152) ltem Length - - -- -- 6-0 mm Replace t f under@I 0 3 In)-- - 10.024-0 --- 032 In) _ 0.2&0 W ~ t hIn 0.02 mm Concentrlcity of valve face O 110 0008 In) Heod thickness Inlet valve @ Valve lifter @ Cylinder. head Fig. 3-151. Removing the valves (Fig. 3-152) Serviceable Limit Standard Value Replace if under 5.48-5.49 mm Stem diameter (0.1 764-0.1 768 in) 5.46 mm 10.21 50 in) Replace if under 62.2-62.4 mm Length @ (2.4488-2.4567 in) 61.8 mm 12.4331 in) Replace if under thickness @ Pd:'o75"8%0236 in) 0.2 mm 10.0079 in) Within 0.02 mm Concentricitv of valve face ' ]10.0008 in) Item 1 2. Valve spring measurement (Fig. 3-153) Outer valve spring Fig. 3-1 52. Valve dimension: Serviceable Limit Standard Value Item Free length 32.1 mm (1.2638 in) Tension 20.3 mm/19-21 kg 10.799 in/41.89546.305 Ibs) iyptii - Inner valve spring Standard Value Item Free length 26.1 mm (l.0276 in1 15.6 mm/10.45- 1 Servicenble Limit 1 !ip2,": I D. Reassembly 1. Install the outer and inner valve springs from the @ I tester - Valve Fig. 3-153. @ Valve Memuring valve tension tappet adjusting hole and compress the springs with a valve lifter and reassemble the valves with valve cotters. 5. VALVE SEAT A. Description The valve seat is repaired with three types of cutter. d width o f the valve The relative location ~ n the seat contact area is accomplished with the valve seat t o p :utter and valve seat bottom cutter while the refacing o f the valve contact area is performed by the 90' cutter. (Fig. 3-154) Fig. 3-154. Valve seat detail 3.2 CYLINDER HEAD AND CYllNDER Valve lapping operation is performed last. This is to obtain a leak-proof seal between the valve and the valve seat. Place a liberal amount of lapping compound on the valve face and lap the valves, applying a slight pressure while rotating the valve back and forth with a suction cup lapping tool. Wash off the compound thoroughly and inspect the valve seat with bluing. (Note) la) When the valve stem is greatly worn, the valve guide is usually also worn. Hence, when a valve is replaced, it also is desirable to replace the valve guide. Since the guide is press fitted, it is recommended that they be replaced with an oversize gu:de. (b) When the valve is assembled, the compound which was used during lapping should be completely removed. Fig. 3-155. Cylinder 6. CYLINDER A. Construction For improved cooling effect and weight, reduction, the cylinder is made of aluminum alloy with a press fitted special cost steel cylinder sleeves. (Fig.3-155) The cam chain guide roller is incorporated at the left hand side of the cylinder. @ .6 m m nuts Fig. 3-156. Removing the cylinder 0. Disassembly 1. Remove,the cylinder head. Refer t o Section 3.2 B. 2. Remove the two 6 mm hex. nuts and the cylinder from the crankcase. (Fig. 3-156) C. Inspection 1 . Measure the cylinder bore, taper, out-of-round with a precision cylinder gauge. (Fig. 3-157) Take the measurement at the top, bottom in both the X and Y axes. itern Taper, j Standard Value 44.0-44.01 mm (1.7323- 1.7327 in) 1 middle and Serviceable Limit Repair i f over 44.1 mm (1.7362 in) 0.005 mm (0.0002 in1 ~~~~~~f ( ~ ~ in, ~ 2 0 @) Cylinder gauge 2. The clearance between the piston and cylinder Fig. 3-157. @ Cylider Measuring the cylinder bore will greatly affect the engine performance. Because the piston is ellipticat, the clearance is controlled very closely. The clearances are not the same, however, if any area is greater than 0.1 mm 10.004 in), the cylinder should be rebored and fitted with an oversize piston. D. Reassembly 1. Install the gasket between the cylinder and crankcase and insert the cylinder over the stud bolts. 2. Make sure that the cylinder gasket and the two dowel pins are installed. 3. During the installation of the cylinder, use a hardwood piston base t o prevent piston movement. Ako use a ring compressor t o prevent ring damages. (Fig. 3-158) @ Piston base. Fig. 3-158. Installing the cylinder 72 3. E N G I N E 3.3 LEFT CRANKCASE COVER 1. LEFT CRANKCASE COVER The purpose of the crankcase cover is t o protect the vital component parts of the engine. The contact point is mounted on the left end of theI crankshaft. 2. A.C. GENERATOR A. Construction The detailed description of the A.C. generator is given in the electrical section. @ 6 mm hex. bolt @ Stator Fig. 3-159. Removing the dynamo stator. B. Disassembly A.C. generator can be disassembled or reassembled without separating the engine from the frame. However, this section describes disassembly of the A.C. generator from the engine which had been separated from the frame, and the cylinder and cylinder head disassembled. 1. Remove three screws and take off the contact breaker cover. 2. Disconnect the primary lead from the breaker @ Spark advancer @ Dynamo rotor setting bolt @ Washer Fig. 3-160. Spark advancer assembly terminal and remove the two contact breaker plate screws t o remove the breaker assembly. 3. Remove the left erankcase cover. 4. Remove the three bolts holding the A.C. dynamo stator and A.C. dynamo stator can be separated. (Fig. 3-1 59) 5. Remove the bolts holding the A.C. generator rotor and the spark advancer assembly can be removed. (Fig. 3-160) 6. Remove the rotor from the crankshaft using the A. C. generator rotor puller. (Tool No. 079332000000) (Fig. 3-1 61) @ Generator rotor puller @ Generator rotor Fig. 3-161. Removing the A.C. generator rotor @ Clutch lifter Fig. 3-162. Clutch lifter thread installation 3.3 LEFT CRANKCASE COVER 74 3. CLUTCH LIFTER THREAD A. Description The clutch lifter thread is located between the clutch lever and the clutch lifter rod. It transmits the action of the clutch lever t o the clutch r o d during starting and changing o f the gears. In other words, the clutch lifter thread regulates the function of the clutch mechanism, and therefore, i t indirectly affects the performance of the motorcycle. (Fig. 3-162) 0. Disassembly 1. Remove the left crankcase cover. 2. Remove the bolt from the adjuster fixing piece and the clutch lever spring. The clutch lifter thread can then be discssembled. (Fig. 3-163) @ Clutch adjuster locking bolt @ 6mm washer @ Adjuster fixing piece @Clutch adjuster Q Clutch lifter thread @ Clutch lever spring Fig. 3-163. Component ports of clutch adiuster C. Reassembly 1. Apply grease t o the clutch lifter thread before assemblying. Use HD type multi-purpose NLGI, N o . 2. 4. CAM CHAIN TENSIONER A. Costruction An automatic cam chain tensioner has been employed t o simplify the maintenance and eliminate the adiustment o f the cam chain. This is done by automatically applying pressure against the tensioner push r o d by means of the cam chain tensioner spring. The force is applied by the push r o d t o one side o f the "seesaw" type, tensioner t o maintain proper tension t o the cam chain at high speed; further, the location of the guide roller has been engineered t o minimize the chain noise. Tensioner roller @ Tensioner arm @ Timing sprocket Crankcase @ Adjust screw lock nut Tensioner adjust bolt @ Tensioner pushrod head @ Tensioner pushrod @ Tensioner spring @ Oil damper chamber Fig. 3-164. Construction of the cam chain tensioner In addition, a manual adjusting feature is also provided t o correct any stretch in the chain as the result of the centrifugalf orce from extended riding. (Fig. 3-164) Disassembly 1. Remove the breaker point cover, point terminal left cover, A C Generator rotor, and then disassemble the A C Generator stator base. 2. Remove the cylinder head and disassemble the cylinder. @ Tensioner adjust bolt Tensioner pushrod @ Cam chain tensioner spring @ Cam chain tensioner Q Tensioner set plate B @ Tensioner set plate A @ Cam chain tensioner roller Compopent parts of the cam chain tensioner Fig. 3-165. 3. Unscrew the three tensioner set plate mounting screws. (Fig. 3-1 66) 4. Loosen the lock nut from the cam chain adjuster screw and after removing the circlip from the adjuster bolt with a plier, the tensioner pushrod and the tensioner spring can be disassembled. C. Inspection Check the cam chain tensioner roller for damage. distortion of the parts, and replace any defective parts. Cam chain tensioner s.~ r i n -a Item O Tensioner plate A @ Tensioner set plate B 6 X 16 cross screw Removing the tensioner set plates Fig. 3-166. 6 set D. / Standard Value Free length 1 68.7mm t2.705in) - . / 20mm/185-215ar I Serviceable Limit 11 ::p ;.:g& in, i Reassembly 1. Perform the reassembly in the reverse order of disassembly. 2. The tensioner adiusting bolt should first be screwed all the way in and then gradually backed off until the proper tension is achieved. Make the adiustrnent by applying a screwdriver t o the upper portion of the bolt head and tighten the lock nut after completion. (Fig. 3-167) If the adjusting bolt is loosened, the cam tensioner will be automatically tightened. 3. Align the " T " marking on the A C Generator rotor @ Tensioner adjust bolt Fig. 3-167. t o the arrow marking on the stator and set the cranrshaft on top-dead-center of compression stroke. @ Lock nut Adjusting the cam chain tension 3.4 RIGHT CRANKCASE COVER ASSEMBLY 1. RIGHT CRANKCASE COVER A. Construction The right crankcase cover and the left crankcase cover, house the engine primary components. The oil filter cover is fitted t o the right crankcase cover and provides the passage for lubricating oil. (Fig. 3-168) 8. Disassembly 1. Remove the kick starter arm from the kick pinion snatt. @ Oil filter cover @ Right crankcase cover Right crankcase cover 2. By removing the ten screws securing the case Fig. 3-168. cover, the right crankcase cover can be removed. 3. After unscrewing the three 6 X 16 screws, the filter cover can be removed. (Caution) During operation, attention should be given t o the t w o 64.5X2 0 ring fitted t o the filter cover t o assure that there are no oil leaks. (Fig.3-169) C. Reassembly 1. Before performing the assembly, inspect the crank- @ Right crankcase cover @ 64.5 X 2 0 ring @ Oil filter cover Fig. 3-169. Component parts of R. cronkcose cover. case and oil filter cover for cracks and also for any damages t o the mating surfaces since they will cause oil leak. 2. Clean the 0 ring and inspect for any damages: replace i f necessary. 3. After installation of the screws, tighten them uniformly t o prevent the covers from warping and consequent oil leak. 3.4 RIGHT CRANKCASE COVER ASSEMBLY 76 2. CLUTCH A. Description and Operation When the right crankcase cover is removed the clutch complete is exposed. To the clutch outer, the clutch spring driving the clutch pressure plate is installed. The clutch plate is installed with the clutch friction disc between the clutch center with four 6 x 2 0 hex. bolts. The clutch plate has internal teeth which fits over the machined grooves cut on the outside of the clutch center. Clutch center in turn is mounted on the transmission main shaft by spline. Hence, it and the transmission main shaft are essentially a single unit. The clutch plate, clutch center, and clutch pressure plate rotate. O n the other hand, to the groove cut on the exterior circumference of the clutch outer, the clutch friction disc is coupled by the collar entering the groove; free wheeling rotation with the transmission main shaft is obtained. Hence, ~ h i ! eth9 c!u!ch is connected, the clutch outer center, four clutch plates, four clutch friction discs, and clutch pressure plate are essentially a single unit through friction exerted by the clutch spring; rotation of the crankshaft is transmitted to transmission system. When the clutch lever is gripped, the clutch adiuster rotates clockwise, the adiustment thread is pushed out by the square-headed thread in the clutch adiuster fitted to the left crankcase cover; this is pushed out by the clutch joint through the clutch rod. The clutch spring is compressed and the four clutch friction discs and four clutch plates become disengaged. Hence, the rotary motion of four outer clutches and four clutch discs is not transmitted t o the clutch center. I 3(J Primary driven gear @ Clutch outer @ Oil opening @ Clutch spring @ Clutch pressure plate @ Clutch lifter joint pi-ce Sectional view of clutch assembly Fig. 3-170. (Fig. 3-170) 8. Disassembly 1. Remove the right crankcase cover. 2. Remove the four 6 x 2 0 bolts @ securing the clutch pressure plate, separate the clutch friction d~scand the clutch plate. (Fig. 3-171) @ 6 x 2 0 hex. bolt @ Clutch assembly Removing the clutch assembly Fig. 3-171. a, 3. By removing the 20 mm set ring clutch center @ can be removed. (Fig. 3-172) 4. Remove the oil filter cap and extract the oil filter rotor. Remove the 16mm lock nut securing the primary drive gear. 5. By pulling up the turn stop, remove the 6 mm hex bolts securing the oil pump. @ 20 mm set ring fig. @ Plier @ Clutch center 3-172. Removing the clutch center I 3. E N G I N E 77 rlon atsc. @ Clutch outer @ Oil pump Fig. 3-173. Rernovina the oil PumD Item -Stnnrlnrrl .-..--.- Vnlutn . -.- - I Thickness Width nf / Serviceable Limit ... . .- .- -.. ... 3.5 mm (0.1378 in1 1 13.7-1 I Reolace if under 3.8 mm 2. Fatigue o f clutch spring. Free length 31.7 mm (1.2480 in1 Tension 21 mm/15-16 kg 10.8268 in/33.075 35.28 lbsl ~~p~~ - I:,g;ddt;. 3. Measurement o f clearance o f the clutch outer notch and the clutch friction disc. @ Clutch outer @ 011pump Fig. 3-174. Oil pump I Item 1 Clearance - Standard Value 0.2 0.35 mm 10.0079-0.01 98 in) Serviceable Limit D. Reassembly 1. Install the primory drive gears. 2. The clutch outer and the oil pump should be coupled by the pump plunger and the unit should be coupled at a right angle to the transmission main shaft and the pump fitting stud bolt. 3. Tighten the two oil pump bolts. 4. Install the right primory drive gear. 5. lnstall the oil filter rotor and oil pump cap. 6. Couple the clutch center t o the spline of the transmission main shaft and set with the 20 mm set ring. 7. Four clutch plates and four clutch friction discs should be placed alternately. Assemble the clutch pressure 'plate, the clutch spring and the 6 x 2 0 bolts. (Note) When the clutch pressure plate is installed, make sure the clutch joint is in place. 8. lnstall the right crankcase cover and screws. I @ Cam chain guide roller @ Cam chain idle roller @ Cam chain tensioner @ Camshaft Q Oil tilter @ Oil filter screen Fig. 3-175. Oil lubrication diagram I 3.4 RIGHT CRANKCASE COVER ASSEMBLY 3. OIL PUMP (Fig. 3-175, 176) The oil is picked up from the crankcase sump and routed through the oil passage to the oil filter where the impurities are removed by the centrifugally operating oil filter. The clean oil is then pressure fed through the upper cronkcase to the right crankshaft bearing. The oil which entsrs the right and left cronkcase outer rings i s separated into two routes, one is fed to the roller bearing and the other enters the crankshaft to lubricate the connecting rod large end through the holes drilled in the crankshaft journals. The connecting rod small end is lubricated by oil mist. The oil from the upper crankcose oil passage i s fed to the top of the cylinder head through the cylinder stud bolts. This oil is fed into the camshaft and lubricates the rocker arm. The oil lubricates the cam chain on i t s way down to the sump. The gears and bearings are lubricated by oil droplets and mists. The normal capacity of oil pump is 3,200 cc (196 cu in) at 7,200 rpm. I @ To crankshaft Q To R. cronkcase cover @ To cylinder head @ Under crankcase @ OilI Fia. 3-176. Sectional view of oil pump. B. Disassembly 1. Remove the right crankcase cover. 2. Remove the oil filter rotor 3. Separate the pump body together with the clutch. 4. By removing the 26 mm circlip, @ the pump rod @ can be separated from the clutch outer [Fig. 3-64) 5. Extract the pump plunger pin @ and remove the plunger @ at the tip of the pump rod. (Fig. 3-65! C. Inspection Refer to section 3.5.1.C on page 39. D. Reassembly 1. Assemble the pump in the reverse order of disassembly. 4. OIL FILTER A. O p e r a t i o n The engine oil is doubly filtered through the centrifugal filter and the mesh screen filter to assure clean supply of oil t o the engine. (Fig. 3-177) The screen filter is on the pump inlet side and the centrifugal filter is on the outlet side. 0. Disassembly 1. Remove the oil filter cover. 2. Remove the four 4 X 16 cross screws and oil filter cap. 3. Pull off the oil filter rotor. C. Reassembly 1. After cleaning o f all the parts, perform the reassembly in the reverse order of disassembly. @ Oil filter rotor washer @ Oil filter cap @ 50.5X 1.5 0 ring @ Oil filter rotor Fig. 3-177. Oil filter I !4NKCASE 3.5 CRANKCASE 1. Upper and under crankcase. A. Description The upper and under crankcases are constructed of lightweight aluminum alloy and can be separated at the center lines of the crankshaft, transmission main shaft and counter shaft. (Note) In the upper surface of the upper crankcase, the cylinder stud bolts are inserted. (Fig. 3-178) Fig. 3-178. Upper crankcase The lower crankcase is equipped with the oil separator and two drain plugs. (Fig. 3-179) B. Disassembly 1. Drain oil in the crankcase. 2. Remove the cylinder head and cylinder in accordance with 3. 2. 1 B and 3. 2. 68. 3. Separate the right cronkcase cover, oil filter, clutch and oil pump in accordance with 3. 4. 1, 3. 4. 2 and 3. 4. 3. 4. Separate the left crankcase cover and A.C. generator in accordance with 3. 3. 1 and 3. 3. 2. 5. Remove the gear shift spindle. Fig. 3-17?, Under crankcase 6. Remove the bolts from the under crankcase, and the upper crankcase can be removed from the under crankcase. (Fig. 3-1 80) C. Inspection Refer t o section 3.6.C on page 41. D. Reassembly 1. Assembly should be performed with attention paid t o the following points : Clean the crankcase and inspect the mating surfaces of the crankcase for sign of leaks, scratches and other damages. @ Under crankcase @ Upper crankcase Fig. 3-180. Removing the under crankcase Apply liquid gasket to the mating surfaces of the case; assemble after drying. 2. O i l separator A. Description The oil separator is located in the forward section of the lower crankcase, directly below the crankshaft. Its primary function is t o control the oil splashed by crankshaft counter weight, prevent oil penetration and controls the oil temperature. B. Disassembly Oil separator can be removed by pulling out the oil separator set bar. (Fig. 3-181) @ 011separator (2) 011separator set bar Fig. 3-181. Removing the oil separator C. Reassembly Assemble the oil separator in the reverse order of di>assembly 3.6 CRANKSHAFT 3.6 CRANKSHAFT A. Construction The crankshaft iournals are made of high carbon steel and the counterweights are of nickel-chromemolybdenum steel, assembled by press fitting. Crankshaft is supported by a roller bearing and a ba!l bearing which take the thrust load and are fixed in place by dowel pins. Sprocket to drive the cam chain is press-fitted on the left crankshaft. The oil is forced into the crank pin by centrifugal force to lubricate the connecting rod bearing. There is also a separate oil route to lubricate the main bearings. (Fig. 3-1 82) Fig. 3-182. Crankshaft assembly (old type) 8. Disassembly 1. Drain oil from the crankcase. 2. Separate the cylinder and cylinder head in accordance with 3.2, 1B and 3.2. 68. 3. Separate the right crankcase cover, oil filter, clutch and oil pump in accordance with 3. 4. 1, 3. 4 . 2 and 3.4. 3. 4. Separate the left crankcase cover and A. C. generator in accordance with 3. 3. 1 and 3. 3. 2. 5. Remove the gear shift spindle. 6. Remove the two 8mm and a 6mm hex nuts from the upper crankcase and remove the five 6mm hex bolts, two nuts and 8mm hex and blind nuts from the under crankcase. lweb side at I^ :."': . I 0.08 mm 12) The clearance in the bearing is measured by fixing the crankshaft on the centers and moving the bearing in the axial and vertical direction. / Item Axial clearance Clearance normal to axis1 1 Standard Value Within 0.05 mm 10.0020 in) Within 0.05 mm 10.0020 in) 1 1 / Serviceable Limit Replace if over 0.1 mm I0004 in1 Replace if over 0.1 mm (0.004 in) When the clearance in the axial direction becomes excessive, the crankshaft will move from side t o side when engine is running and produce undersirable noises as well as causing uneven wear to the cylinder, piston and the timing sprocket. D. Reassembly Assemble the crankcase in the reverse order o f disassembly. ~ i 3-183. ~ . Measuring the crankshaft run out. 3. E N G I N E 2. CONNECTING RODS A. Description The connecting rods are o f molybdenum steel and have a n H-shaped section; The roller (2.5 X 8.5mml is hold b y the roller retainer made o f special aluminum alloy. Staggered rollers are used i n order t o increase the load capacity. 1. Measuring the deflection at the piston end of the connecting rod. page 43 and 44. Refer t o section 3.7.28 on 3. PISTON A. Description Refer t o section 3.7.3.A on page 44. 8. Disassembly Refer t o section 3.7.3.B C. on page 44. Inspection 1. Before inspection, carbon adhering t o the piston head o r ring groove should b e removed, using care not t o scratch the piston. [Caution) Sandpaper should not b e used for carbon, use a carbon scraper. removing 2. Piston outside diameter. Item Head diameter Major diameter / Standard Value 43.50-43.55 mm (1.713- 1.715 in) 43.98-44.0 mm (1.732- 1.732 in) Serviceable Limit Replace i f under 43.4 mm (1.7087 in) Replace if under 43.9 mm (1.7283 i*I 3. Rina clearance when a new piston ring i s - Groove Standard Value Oil ring 4. Piston pin hole. Item Bore @ Dial gauge @ Piston Fig. 3-184. Measuring piston pin hoie 0.01 -0.045 mm Serviceable Limit Replace i t over (Fig. 3-184) Standard Value 13.000- 13.006 mm (0.51 18-0.51 20 in) Serviceable Limit Replace it over 13.05 mm (0.5128 in) 3.6 CRANKSHAFT 5. There are three types of oversize piston at intervals of 0.25 mm (0.01 in.) D. Reassembly Refer to section 3.7.3.D on page 46. 4. PISTON RINGS Refer to section 3.7.4. on page 46. B. lnspection 1. When the piston ring has been removed, the gap should be measured. It should be inserted approximately 15 mm (0.6 in.) from skirt of the cylinder at right angle to the center line. Measurement of the gap should be made with a thickness gauge. (Fig. 3-1 85) / ltem Standard Value / 10.0059-0.01 38 in1 / Oil ring 10.0059-0.01 38 in) 0.15-0.40 mm 10.0059-0 01 58 in) 1 @ Thickness gauge @ Piston ring Fig. 3-185. Measuring the piston ring gap Serviceable Limit Replace i t aver 0.8 mm 10.032 in) Replace if over 0.8 mm 10.032 in) Replace if over 0.8 mm (0.032in1 2. Tension of the piston ring i s measured with a tension measuring instrument. ltem - - -- Top ring Second ring Oil ring C. Standard Value 0.34-0.63 kg 10.750- 1.389 Ib) 0.28 -0.57 kg 10.617- 1.257 1bl 0.50-0.80 kg I1 .I03- 1.764 Ibl Serv~ceable -. Lim~t Replace if under 0.24 kg 10.529 Ib) Replace if under 0.2kg 10.441 Ibl Replace i f under 0.4 kg 10.882 Ibl Replacing t h e p i s t o n r i n g s 1. When a piston ring is reassembled, it should be fitted to the cylinder. lnspection should be made to determine if the gaps of the top and second rings are proper. If the gaps are somewhat less. they should be corrected with a file. (Caution) (a) The gap should be filed perpendicular to the ring (bl If the piston ring gap i s too small, seizure between - the rina and cvlinder occurs due to thermal expansion; if the gap is too large, oil penetration or gas leakage occurs. When piston ring is assembled on the piston, any interference between the ring and the groove may It i s necessary t o prevent smooth operation. inspect for clearance, when new ring is fitted t o the groove, by rotating the ring around the circumference. (Fig. 3-1 86) Fig. 3-186. lnspection of the piston ring by rotating around the piston 3.7 TRANSMISSION 83 3.7 TRANSMISSION A. Description The transmission receives the rotary power from the crankshaft and through a series of gears, changes it to the desired speed and then transmits it to the drive sprocket to drive the rear wheel. All the gears are fully constant meshed, assuring smooth gear change. B. O p e r a t i o n Fig. 3-187. Fig. 3-188. Low gear Second gear Low : (Fig. 3-1 87) The power from the crankshaft is transmitted through the clutch to the spline fixed driven gear on the transmission main shift O. - The Dower from the transmission main shaft @ is transmitted from the main shaft drive gear to the counter shaft low gear @. However, the counter shaft second gear @ which i s splined to the counter shaft and IS moved aga~nstthe low gear Q by the shift fork and is locked by means of a dog, forming an single unit with the counter shaft to transmit the driving force to the drive sprocket @ mounted on the left end of the counter shaft. Second : (Fig. 3-1 88) The main shaft third gear @ which i s spline slide fitted to the main shaft @ is moved by the shift fork to lock with the second gear @ by means of a dog, thus permitting the transmission of power from the main shaft to the counter shaft @ . by . meshing - the main shaft second gear with the splined counter shaft second gear @ hence to drive the sprocket @. Third : (Fig. 3-189) The power from the transmission main shaft @ IS transmitted to the counter shaft third gear @ by meshing with the main shaft third gear Q. The counter shaft second gear @ which i s spline slide fitted is moved by the shift fork to lock with the free rotat~ng third gear @ by means of a dog, this causes the counter shaft @ to rotate and in turn drives the sprocket @. Fig. 3-189. Third gear Fig. 3-190. Top gear Top : (Fig. 3-1 90) The main shaft third gear @ is moved by the shift fork to lock with the free rotating top gear @ by means of a dog, thus permitting the transmission of power from the main shaft @ to the counter shaft by meshing the main shaft top gear @ with the fixed counter shaft @ (top gear) to drive the sprocket @. 3.8 GEAR SHIFT 84 Neutral : (Fig. 3-191) The gears are not locked. The main shaft low gear @ is meshed with the counter shaft low gear @ and the main shaft third gear @ is meshed I with counter shaft third gear @, however, the counter shaft gears rotate freely and therefore, no power is delivered t o the sprocket @. C. Inspection Fig. 3-191: 0.01 6-0.045 mm (0.0006-0.0018 in) Top gear Neutral Replace if over 0.1 mm (0.004 in) 2. Counter shaft t o counter shaft gear clearance. Serviceable Limit 3. Bearing clearance. (Fig. 3-1 92) Replace if over 0.1 mm (0.004 in) Radial 0.01 -0.025 mm Replace if over 4. Shift drum groove (Fig. 3-193) Standard value : 6.0-6.15 mm (0.236-0.242 in.1 3.8 A. @) Bearing @ Dial gauge Fig. 3-192. Measuring clearance of the bearing Fig. 3-193. Sectional view of gear shift drum GEAR SHIFT Description As the gear change pedal is depressed, the gear shift spindle is rotated and the gear shiit pawl on the end of the gear shift arm engages with the gear shift pin on the right side of the gear shift drum and CbUSeS it t o turn. A groove is machined on the surface of the drum, forming a cam, and as the drum is rotated, the shift fork riding in the groove is actuated by the contour of the groove to perform the gear shifting action. Further, there is a gear shift return spring which brings the pedal back t o the original position and prepares for the next gear operating sequence. (Fig. 3-194) 3. ENGINE I B. Disassembly 1. Separate the crankcase to the upper arid lower half by following the procedure outlined for the disassembly of the transmission. 2. Remove the shift fork guide pin clip installed on the shift fork and separate the guide pins. 3. Remove the neutral switch rotor and stator installed on the right side of the shift drum. 4. Remove the shift drum stopper arm pivot which holds the shift drum stopper plate and then remove the stopper. (Fig. 3-195) 5. The gear shift, gear shift return spring, and gear shift spindle side stopper are all assembled by a circlip, therefore, by removing the circlip with the snap ring plier, the spindle can be disassembled. (Fig. 3-196) 6. Remove the gear shift return spring with a spanner or with a deep walled socket wrench. 7. Loosen the gear shift fork guide screw in the upper crankcase and remove; at the same time, remove the shift drum guide collar. 8. Pull out the sbift drum from the side of the crankcase. (Fig. 3-197) i @ Geor shift spindle @ Gear I shift fork Fia. 3-194. @ Geor shift drum @ Gear shift return spring Sectional view of aear shift rnrrhnnicm 1 C. Inspection 1. Inspect the gear shift fork for bend. 2. Check the gear shift guide pin for excessive wear. 3. Check the shift drum stopper for looseness due t o excessive wear. 4. Check the gear shift spindle return spring for loss of tension. 5. Check the return spring pin for security. D. Reassembly 1. Insert the gear shift drum from the right side of the upper crankcase and assemble the gear shift fork within the crankcase being careful that the gear shift fork is centrally positioned. @ Shift drum stopper plate @ Shift drum stopper Fia. 3-195 Removing the shift drum stopper. 2. Assemble the shift fork with the gear shift fork guide pin. Make sure that the gear shift fork guide pin is inserted in the correct position. 3. Assemble the gear shift drum stopper. 4. Assemble the neutral switch rotor and stator ; check to make sure that the switch is making contact in the neutral position. 5. Insert the gear shift spindle from the right side and then assemble the gear shift spindle side stopper form the left side and lock in position with the circlip. 6. Assemble the crankshalt and the transmission gear assembly into the upper case. Assemble and bolt the lower crankcase. Fig. 3-196. Removing the gear shift spindle 7. Finally, assemble the crankshaft in. accordance with the assembly procedure. 3.9 KICK STARTER 3.9 86 KICK STARTER A. Description The kick starter is designed t o prevent the ratchet noise following the start of the engine; it is of the same design as the C50 and C65. As the kick starter pedal is depressed, the kick starter spindle will revolve, causing the rathet t o move along the spiral groove in tho drum due t o action of the ratchet spring, and with the pinion t o transmit the action t o the counter shaft low gear, main shaft primary driven gear and then finally rotates the crankshaft which is directly driven by the primary drive gear, (Fig. 3-199) Fig. 3-197. Removing the gear shift drum. When the engine starts, and as the pinion speed exceeds the spindle speed; the ratchet due to the rotation of the pinion will turn in the left hand direction in reference t o the spindle. Because of the left hand square thread action of the set spring, the ratchet will separate from the pinion. The kick starter spring returns the spindle t o the original position, disengaging from the pinion and is poised for the succeeding kick starter operation. 8. Disassembly 1. By following the disassembly procedure for the transmission, the upper and lower crankcases can be separated permitting the disassembly of the kick starter spindle. @ G e a r shift fork @ Guide pin clip Fig. 3-198. Installing the gear shift drum i I 2. Remove the kick starter spindle. C. Inspection Check ratchet and the gear teeth of the pinion ratchet for excessive wear. D. Reassembly Perform the assembly in the reverse order of disassembly. I I @ Kick starter spindle @ Kick starter ratchet @ Kick starter ratchet spring @ Kick starter pinion @ Counter shaft low gear @ Kick starter spring Fig. 3-199. &Kick l starter spindle Fig. 3-200. Sectional view o f kick starter. @ Kick starter spring Fig. 3-20]. @ Kick starter spindle Kick starter spring. 3. E N G I N E 87 The kick starter for engine No. CB125E-2011645 or CL125E-2007602 and subsequent is equipped as shown in Fig. 3-202. @ Low gear 3.10 Q Kick starter :pindie @ Circlip @ Friction spring @ Kick sto~,er pinion @ Kick starter spring CARBURETOR (CB125, Cl.125) CB125 and CL125 are equipped with the carburetor identical to those used on the CB/CL175 which is described on page 56 through 61. The carburetor setting for the CB/CL125 are shown in the table below. Setting specification 1 1 Model Setting mark CB125, Air iet # 92 # 150 Air bleed AB1 0.6 mmX4 AB2 None AB3 0.6 mmX2 AB4 None Main iet / Needle let 2.6 mm X 3.6 mm a125 CB125 Jet needle / Cut-away (throttle valve) CL125 CBC # 2.0 18234 - 2 stage 18231 - 2 stage (width 1.2 mm, Depth 0.2 mml Air screw Slow jet 0.7 mm X 2 0.7 mm X 2 1.7 mm Valve seat Pilot outlet Fuel level I / 0.9 mm, Pitch 7.0 mm 21 mm (0.827 in1 4.1 STEERING HANDLE 88 4, FRAME 4.1 STEERING HANDLE A. Description The steering handle @ is made o f high strength steel pipe, and is mounted on the front fork top bridge with the handle pipe holder @. The fork top bridge is attached t o the front cushions by t w o front fork bolts. All control cables are exposed t o simplify steering handle replacement. (Fig. 4-1-1, 2) @ Steering handle pipe @ Steering damper knob @ Handle' pipe holder Fig. 4-1-1. CB type steering handle Disassembly 1. T o disassemble the front brake cable @, push the brake arm toward the braking position t o p r o v ~ d e slack t o the cable and then disconnect the brake cable from the brake arm. Remove the 5 mm cross screw and pull out the speedometer cable @ from the front brake panel. (Fig. 4-2) @ Steering handle pipe CL type steering handle Fig. 4-1-2. Disassemble the clutch cable lower end by loosening the three 6 mm screws on the .drive chain cover A and disconnect the clutch cable from the clutch lifter. Disconnect the lower end of the throttle cable @ by removing the carburetor cap 0, pulling put the throttle valve @ and then disconnecting the throttle cable from the valve. (Fig. 4-3) @ Front brake cable @ Speedometer cable Fig. 4-2. Removing the speedometer and brake cables Throttle cable @ Carburetor cap @ Throttle valve Fig. 4-3. Disconnecting the throttle cable from the throttle valve 4. 89 FRAME Access to the wire harness connectors for disassembly of the electrical equipment i s made by removing the headlight unit to expose the connectors housed in the headlight case. Remove the 6 mm snap pin under the steering stem and the steering damper knob. Loosen the four 8 x 3 6 handle mounting bolts t o remove the steering handle @ from the fork top bridge. The steering handle can be removed together with the cable and wires @ as a complete unit. (Fig. 4-4) Fig. 4-4. . . - Removing the steering handle pipe 7. Unscrew the brake and clutch cable adiusting bolts .and disconnect the inner cable from the levers. 8. Disassemble the throttle cable by unscrewing the two 5 x 2 5 cross screws t o separate the light switch assembly. Disconnect the throttle cable from the handle grip pipe. (Fig. 4-5) C. Inspection 1. Check the throttle, clutch and front brake cable for wear, damage, kinks and unsmoothness of operation. @ Throttle cable @ Light switch assembly Fig. 4-5. Removing the throttle cable 2. Check the handle levers for operation. unsmoothness of 3. Check the handle pipe for bend and twist. 4. Check all the switches for improper operation and also check the electrical leads for damage D. Reassembly 1. Connect the upper ends of the cables t o their respective levers. 2. Position the cables and electrical leads in their proper location and then clamp the steering handle in place between the upper and lower handle pipe holders with the four mounting bolts. 3. Route the cables though the supports and the @ Lock nut @ Throttle cable adjuster Fig. 4-6. Adjustment of the throttle cable electrical leads into the headlight case. 4. Connect the clutch cable end to the clutch lifter thread, the brake cable end t o the brake arm and the throttle cable end t o the throttle valve. Adjust the respective cables to the proper specification with the adjust bolt at both ends of the cable assemblies. Tighten the lock nuts after completing the adjustment. (Fig. 4-6, 4-7, 4-8, 4-9) @ Lock nut @ Adjusting nut Fig. 4-7. Adjustment of the front brake coble Free travel : Throttle cable grip twist angle 9 t o 10 degrees Front brake cable (at end of lever) 10 t o 30 mm (0.4 t o 1.2") Clutch cable (at end of lever) 20 t o 30 mm (0.8 t o 1.2") 4.2 FRONT CUSHION @ Clutch adjuster Adjustment of the clutch play @ Clutch adjuster locking bolt Fig. 4-8. @ Clutch adjusting bolt @ Locking nut Fig. 4-9. Adjustment of the clutch play. @ Headlight case @ Electrical leads Joining the leads. Fig. 4-10. 4.2 FRONT CUSHION A. Description The front and rear cushions should not b e considered t o b e functioning independently. The suspension and dampening components ditectly influence the steering characteristic and stability of the motorcycle. The front fork must not only withstand the load from the vertical cushioning but also the horizontal force resulting from the steering function. The front cushion spring is designed with t w o different pitches; this is t o provide a broader range of effective cushioning. The oil damper contains 135- 145 cc (8.27 -8.88 cu. in) hydraulic fluid. 90 97 4. FRAME @ Front fork bolt @ Front fork washer @ 8.4X2.4 0 ring @ Fork top bridge @ FrontIcushion spring @ Front fork upper cover @ Front fork rib @ Front fork rib packing @ Steering stem @ Front fork under cover @ Front fork pipe complete @ Rebound stroke (19mm: 0.748 in) @ 41mm internal circlip @ Front fork oil seal @ Bottom case cover @ Front fork pipe guide @ Fork pipe stopper ring @ Fork valve stopper ring @ Front damper valve @ Piston stopper ring @ Front fork piston @ Fork piston snap ring @I Front fork bottom case comp. @ Fork drain cock packing @ 6 x 8 hex bolt Fig. 4-10-1. (CB125) @ Front fork bolt @ Front fork washer @ 8.4X2.4 0 ring @ Fork top bridge @ Front cushion spring @ Front fork cover @ Steering stem @ Front fork pipe comp. @ Front fork dust seal @ Front fork boot @ Rebound stroke 119mm : 0.748 in) @ 41mm internal circlip @ Front fork oil seal @ Front fork pipe guide @ Fork pipe stopper ring @ Fork valve stopper ring @ Piston stopper ring @ Front fork piston @ Fork piston snap ring 6Ix 8 hex bolt @ Fork drain codk packing @ Fig. 4-10-2. (CL1251 4.2 FRONT CUSHION 92 @) Front fork upper cover cap @ Front fork cover upper cushion @ Front fork bolt @ Front fork washer Q 8.4X2.4 0 ring @ Fork top bridge @ Front cushion spring @ Front fork upper cover Steering stem @ Front fork lower cover @ Front fork cover lower cushion @ Front fork rib Front fork pipe comp. @ 41mm circlip @ Front fork oil seal @ Bottom case cover @ Staking Front fork pipe guide @ Fork pipe stopper ring @ Fork valve stopper ring @ Front damper valve Piston stopper ring @ Front fork piston @ Fork piston snap ring @ Front fork bottom case comp. @ 6 x 8 hex. bolt Fork drain cock packing Fig. 4-10-3. lCB1751 @ @ @ @ @) Front fork bolt @ Front fork washer @ 8.4X2.4 0 ring @ F,ork top bridge @ Front cushion spring @ Front fork cover @ Front fork cover lower cushion @ Steering stem @ Front fork dust seal @ @ @ @ @ Front fork pipe comp. @ Front fork cover upper cushion @ Front fork upper cover cop @ Front fork boo1 Front I fork pipe guide @ Front pipe stopper rind 4lmm internal circiip @ Front fork oil seal @ Front fork valve stopper ring @ Front damper valve @ Piston stopper ring @ Front fork piston Fork piston snap ring @ Front fork bottom case @ 6 x 8 hex bolt @ Drain cock packing Rebound stroke 11 9 mm : 0.748 in1 Fig. 4-10-4. lCL1751 RAME B. Disassembly 1. Remove the steering handle in accordance with section 4.1 8. 2. Straighten the tabs of the 8.2 mm tongued washer A and remove the front arm stopper bolt. Loosen the front axle nut and pull out the axle ; the front wheel will disengage from the front forks. (Fig. 4-1 1) O Front arm stopper (2) Front wheel c'able. Speedometer cable Removing the front wheel 6 Front brake Fig. 4-11. 3. Remove the front fender @ by unscrewing the 6 mm bolts @ and 8 mm bolt @. (Fig. 4-12) @ 8 X28 hex. bolt @ 6 X 16 hex. bolt Removing the front fender @ Front fender Fig. 4-12. 4. Remove the headlight rim, headlight sealed beam unit, two 5 mm nuts @ and then separate all electrical leads. Remove the speedometer assembly @. (Fig. 4-13) @ Speedometer Removing the speedometer @ 5 mm hex. nut Fig. 4-13. 5. Unscrew the two headlight case mounting bolts and remove from the front fork. 6. Unscrew the steering head stem nut. @ Steering heod stem nut @ Front fork bolts Fig. 4-14. Unscrewing the steering heod stem nut (Fig. 4-14) 4.2 FRONT CUSHION 94 @ Front fork assembly 9. Remove the 41 mm internal circlip and pull out the front fork pipe from the front fork b o t t o m case. , 10. Remove the front fork pipe guide, stopper ring, front damper valve and piston. (Fig. 4-16) C. Inspection - 1. Front cushion sorina , Model Item Stondard Value / / Tilt Serviceable Limit Replace if under 384 mm (15.1 in) fik4$mnl Free length 1 Within 1.5' 5 ~ & n tfork bii sear --Replace if under 384 mm (15.1 in) 41 4.7 mm Free length116.337 in) Loading 294.6 mm/86 kg (11.608 in/189 Ibsl - Tilt within 1.5O - @ Front fork pipe guide @ Piston stopper ring @ Fork valve stopper ring @ Front damper valve @ Piston stopper ring @ Front fork piston @ Fork piston snap ring Fia. 4-16. Removina the fork piston 378 ~mm (1 i f4.9 under Free length ~ ~ ~ ~ 7Replace ~ nin) l 294.4 mm/93 kg (11.591 in/205 Ibs) Tilt within 1" Loading / / 2. Damping capacity Item Damping capacity 14- 18kg/0.5m/sec 130.8-39.61bs/ 19.7in./sec.I All model Capacity 35_ 45 cc ,8.26-8.87 cu. in.) 3. Front fork piston - - O Front @ Front 9 Front fork pipe @ Front fork 011seal fork pipe guid'e @ Front fork piston cushion spring Front fork pipe ossembly Fig. 4-17. Replace i t over 0.04 mm 10.001 6 in1 Within 0.02 mm 4. Front fork bottom case ltem Inner Taper / / Standard Value 35.53-35.57 mm Within 0.02 mm 10.0008 in1 ( I Serviceable Limit Redace if over 35:72 mm 11.4063 in) Replace if over 0.04 mm (0.0016 in1 Replace if over 0.04 mm (0.001 6 in) @ Front fork pipe @ Front cushion spring @ Front fork bottom case Fig. 4-1 8. Reassembling the front cushion 95 4. FRAME D. Reassembly 1. Assemble the front damper valve and front fork piston on the front fork pipe, and lock with the front pipe rings. (Fig. 4-17) 2. Fill the front fork with SAE 10W30 hydraulic fluid. I135 cc- 145 cc : 8.26-8.87 cu in) 3. Insert the front fork pipe assembly into the fork bottom case and push the front fork oil seal into place, being careful not t o damage and then set the internal circlip. (Fig. 4-18) 4. After completing the assembly, install the front fork into the steering stem. (Fig. 4-19) 5. Assemble the front fork to the top bridge. 6. Assemble the steering handle to the top bridge in accordance with section 4.1D. 7. Install the headlight case, connect the electrical leads within the case and then assemble the light unit. 8. Install the front fender on the front fork. 9. Assemble the front wheel to the front fork. 10. Connect the speedometer cable to the gear box and connect the hont brake cable and complete the adjustment. 11. Connect and adiust the throttle cable. 4.3 STEERING STEM A N D STEERING HANDLE LOCK A. Construction The steering stem is mounted by the bolts to the front fork through the top bridge plate and supported by upper and lower sets of ball bearings in the steering head on which it pivots. @ Steering head stem nut @ Steering stem washer @ Steering head top thread @ Steering top cone race Steering head dust seal washer @ Steering stem @ Steering bottom cone race @ Steering head dust seal @ 8 x 3 2 hex. bolt @ Handle lock spring @ Handle lock @ Handle lock case cover @3I mm flat washer a @ 3 x 8 cross screw Fig. 4-20-1. Steering stem and steering handle lock ICB/CL1251 4.3 STEERING STEM AND STEERING HANDLE LOCK 96 @ Steering damper locking spring @ Steering head stem nut @ Steering stem washer Q Steering head top thread @ Steering top cone race @ Steering bottom cone race @ Steering head dust seal @ Steering head dust seal washer @ Steering stem @ 8 x 3 2 hex. bolt @ Handle I lock spring Handle lock @ Handle lock case cover @ 3 mm flat washer @ 3Ix 8 cross screw @ Steering damper knob Steering I damper plate B @ Steering damper plate A @ Steering damper friction disk @ Friction disk anchor bolt @ @ Steering damper spring @ Steering damper nut @ 6 mm snap pin Steering stem and steering handle lock ICB/CL175) Fig. 4-20-2. @) Damper lock spring setting bolt B. Disassemble 1. Separate the steering handle pipe in accordance with section 4.1 8. 2. Remove the front cushion i n accordance with section 4.28. 3. Remove the steering stem t o p thread and draw the steering stem @ out o f the head pipe @, being careful not t o drop the steel balls Q. (Fig. 4-21) @ Steering stem bottom cone race @ Steering stem Removing the steering stem Fig. 4-21. 97 4. FRAME C. Inspection 1. lnspect steel balls for cracks, wear and other damages. 2. lnspect the cone and ball races of both the top and bottom for any wear or damages. 3. lnspect the steering head dust seal for wear and damage. 4 . lnspect the steering stem for twist and bend. (Fig. 4--22) Bend @ Steering stem @ Small dial gauge @ Height gauge @ Magnetic V block Fig. 4-22. Measurement of the steering stem bend Standard Valuel Within 0.05 mm 10.002 in) -Serviceable Limit -- - 5. Inspect the thread end of the steering stem for damaged threads. 6. lnspect the spring on the steering handle lock for breakage. D. Reassembly 1. Mount the steering handle lock on the steering stem. 2. Mix the #8 steel balls (36 total in grease and lay into the lower and upper ball races and carefully insert the stem to prevent dropping the balls. Tighten the steering head top thread. (Note) Special care is required t o tightening the top thread. It must be tightened in conjunction with the steering stem nut and the front fork bolt. When the stem nut is properly tightened, the front wheel should move t o either lock under its own weight when a slight force is applied. Further there should not be any looseness in the vertical or the horizontal directions. 3. Assemble the front cushion and front wheel. 4. Install the steering handle. @ CB type fuel tonk Fuel tank Fig. 4-23-1. 4.4 FUEL TANK A. Construction The fuel tank is placed on the frame body directly above the engine and is installed on the frame body through the fuel tank cushion. The knee grip rubber, as well as the tonk mark, fitted with the tank side cover. is installed on the fuel tank. (Fig. 4-23) @ CL type fuel tank Fig. 4-23-2. Fuel tank 4.4 98 FUEL TANK @ Fuel feed tube Removing Ihe fuel feed tube @ Fuel cock Fig. 4-24. 4. After the emblem is removed, the 6 X 8 bolt is loosened, the side cover pushed forward and @ Fuel tank Fig- 4-25. Normally a water test is performed at a specified pressure. However, exercise precaution since @ Fuel cock Fig. 4-26. the he'tank @ Fuel tank Removing the fuel cock @ 6 x 2 5 cross screw @ Fuel cock body Removing the fuel cock body Fig. 4-27. @ Fuel tank 99 @ Clip Fig. 4-28. 4. FRAME @ Fuel tank side cover lnstalling tonk side cover 3. Fit the front and rear rubber cushions to the frame body. The front rubber cushion should be inserted by pushing the fuel tank from the rear. Install the fuel tank rear end by placing it under the rear frame. (Fig. 4-30) 4. Fit the fuel line to the carburetor and secure it by the clips. @ Fuel tank side cover @ 6 X 8 mm hex, bolt @ Fuel tank Fia. 4-29. Sectional view of side cover retaining bolt @ Fuel tank lnstalling the fuel tonk Fig. 4-30. 4.5 FRAME BODY Construction The frame body is the main structural member around which the motorcycle is assembled. it mounts the engine and is supported on the front and rear wheels. The frame is made strong to support the weight of the engine, rider and carrier load and in addition, it must be substantial to receive the dynamic reaction imposed by the road and riding conditions under the load. Fig. 4-31. Frame body The frame must be rigid t o provide good steering characteristic and at the same time lightness is desirable for lose in handling and for good riding performance. (Fig. 4-31) 4.5 FRAME BODY B. Disassembly 1. Remove the engine from the frame in accordance with section 3.18. 2. Remove the steering handle in accordance with section 4.18. 3. Remove the front cushion in accordance with section 4.28. 4. Disassemble the steering stem in accordance with section 4.38 5. Remove the seat and fuel tank in accordance with section 4.48. 6. Disassemble the rear wheel in accordance'with section 4.1 38. 7. Remove the rear cushion in accordance with section 4.1 1B. 8. Disassemble the rear fork and rear fender in accordance with section 4.1 08. 9. Remove the air cleaner and tool box in accordance with section 4.68 and 4.98. 10. Detach all electrical components from the frame. 11. Remove the stand in accordance with section 4.78. @ Plostic hammer @ Wood Fig. 4-32. Removing ball race @ Head pipe C. Inspection 1. lnspect the weld joint for any breaks and cracks. 2. lnspect the steering head pipe for twist, behds and misalignment. (Note) Hammer Fig. 4-33. @ Insertion tool Driving ball race The ball races should be fitted to the steering head pipe with light driving (interference f i t : 0.01 rnm-0.05 mmj0.0004-'0.002 in) and must be bottomed so that it is not cocked. (Fig. 4-32, 33) 4. lnspect the frame paint coating for any chips and rust spots. D. Disassembly Perform the assembly in the reverse order of disassembly. Fig. 4-34. Seot @ Steering head pipe 4. 7 01 Fig. 4-35-1. FRAME Removing the seot 3. Remove the air cleaner @ by unscrew the two 5 X 12 bolts @ and the 5 X 16 cross screw @. (Fig. 4-35-2) @ 5 X 16 cross screw Kemoving the alr cleaner C. Inspection Fig. 4-35-2 1. lnspect the air cleaner case for deformation. 2. lnspect the seat leather for wear and tear. D. Reassembly 1. After the seat is fitted, install the seat settirg rubber and two seat damper rubbers. 2. Install the two seot setting bolts. 4.7 STAND A. Construction For reducing the weight, a bent pipe is used for the stand. The section which contacts the ground when the stand is erected has an oval plate welded t o increase the contact area. The step bar (CB175) is mounted under the crankcase with four 8mm bolts and nuts. ICL175 : four 8 X 25 bolts1 (Fig. 4-36) @) M a i n stand Fig. 4-36. @ Stopper rubber ICB type) 4.6 AIR CLEANER CASE AND SEAT 4.7 STAND B. Disassembly 1. Remove the muffler i n accordance with section 3.1B and detach the step bar. 2. Unhook the main stand spring. 3. Place a support block under the engine and remove the 10 X 125 bolt. (Fig. 4-37) 4. The main stand can be removed from the frame. C. Inspection 1. Inspect the stand and step bar for bend ; the pad on the step bar should also be inspected for wear. @ 10 X 125 hex bolt Fig. 4-37. @ Main stand ~ e m d v i nthe ~ main stand D. Reassembly Perform the assembly in the reverse order of disassembly. @ 1 0 X 125 hex. bolt @ Main stand spring @ Main stand @ Main stand distance collar Q lOmm spring washer @ 10 mm hex. nut @ Stopper rubber Main stand (CB/CL125) Fig. 4-38-1. 7 02 4. @ 10x125 hex. bolt @ Main stand spring @ 10 mm hex. nut Fig. 4-38-2. Main stand (CB/CL175) 4.8 FRAME @ I, Main stand distance collar @ Main stand @ l O m m spring washer EXHAUST PIPE A N D MUFFLER A. Construction The muffler and the exhaust pipe have been made into an integral welded unit t o greatly improve the silencing - effectiveness o f the muffler. The length and bend i n the exhaust pipe and the volume o f the muffler will have a great effect on the engine output. The exhaust gases noise is reduced as i t is routed through the narrow passages i n the muffler. The remaining noise is diffused by the diffuser pipe t o assure greater silencing effectiveness o f the muffler. B. Disassembly 1. Remove the t w o 6 mm nuts at the cylinder head. 2. Loosen the four 8 x 2 5 bolts and remove the footrest bar. 3. The muffler is bolted t o the frame together with the step; therefore, loosening the 2 x 5 8 step mounting oolts will also separate the muffler from the frame. (CB175) I @ Inner pipe g~Muffler half (3) Separator A Sectional view of muffler Fig. 4-39. @ Separator B @ Separator C 4.8 EXHAUST PIPE AND MUFFLER C. Inspection 1. Inspect the muffler gasket for damage. 2. Inspect the muffler for cracks, dents and other defects. D. Reassembly Perform the assembly in the reverse order of disassembly. (Note) First install the exhaust pipe joint but d o not tighten as it will make the installation of the other muffler mounting bolts difficult. The tightening of the exhaust pipe joint nuts should be made last. 8 x 7 1 hex. bolt @ Exhaust pipe joint @ Exhaust pipe joint collar @ Exhaust pipe gasket @ 6 mm hex. nut @ 8 mm spring washer @ 8 mm spring wosher @ 8 mm hex. nut @ Right exhaust muffler @ Left exhaust muffler @ 8 x 3 6 hex. bolt @ 8 mm spring washer @ 8 mm flat wosher @ 5 mm spring washer @ 5 x 8 hex. bolt @ Exhaust diffuser pipe Fig. 4-40-1. CB125 MuRler 7 05 4. FRAME Q Exhaust pipe joint collar @ Exhaust pipe gasket @ Exhaust pipe joint @ 6 mm hex. nut 6 mm flat washer @ 6 x 3 2 hex. bolt @ Right exhaust pipe @ Exhaust pipe bracket A @) Exhaust pipe bracket B @I 8 mm hex. nut @ 8 mm flat washer @ Muffler hanger stay @ 8 mm spring wosher @ 8 mm flat washer @ 8 mm spring wosher @ Exhaust pipe setting bolt @ 6 x 2 0 hex. bolt @ Muffler band @ Muffler packing @ Left exhaust pipe Exhaust pipe protector @ 6 mm flat wosher Fig. 4-40-2. CL125 Muffler @I @ 6 x 1 2 cross screw @ 6 X 10 cross screw Exhaust pipe joint collar @ Exhaust pipe gasket @ Right exhaust muffler @ Left exhaust muffler @) Pillion step pin @ Pillion step rubber @ Pillion step washer @ Pillion step bar @ Left pillion step arm @ 8 X 16 hex. bolt @ 8 X 36 hex. bolt @ 6 mm hex. nut @ 6 mm flat washer @ 8 mm spring washer @ 1.6X 15 cotter pin Fig. 4-40-3. CB175 Muffler @ Exhaust pipe joint @ Right pillion step arm 4.9 AIR CLEANER AND TOOL CASE 7 06 Left exhaust pipe @ Exhaust pipe joint @ Exhaust pipe joint collar @ Exhaust pipe protector Exhaust pipe bracket A @ Exhaust pipe bracket B @ Exhaust pipe gasket @ Right exhaust pipe Muffler hanger stay Muffler band @ Muffler packing @ Left pillion step arm @ Pillion step pin I pipe setting bolt @ 6 x 2 0 hex. bolt Pillion step rubber @ Pillion step washer @ Pillion step bar @Exhaust 6 x 3 2 hex. bolt @ 8 X 16 hex. bolt @ 6% 12 cross screw @ 6 X 10 cross screw @ 6 mm hex. nut 6 mrn spring washer @ 8 mm spring washer @ 8 mrn spring washer @ 6 mm flat washer @ 8 mm flat washer @ 1.6 X 15 cotter pin Fig. 4-40-4. CL175 Muffler 6 4.9 AIR CLEANER AND TOOL CASE Filter paper is employed i n the air cleaner for increasing the filter p e r f o r m a ~ c e by enlarging the surface area. As the motorcycle is equipped with twin carburetors, air cleaners are mounted o n both the right and left sides. B. Disassembly 1. Loosen the t w o 6 X 12 nuts and remove the right and left air cleaners. (Fig. 4-41) 2. Remove the air cleaner connecting tube from the carburetor by loosening the 5 mm cross screw. 3. The air cleaner can b e separated from the frame. 4. Separate the t o o l b o x @ b y removing the t w o 6 mm bolts. (Fig. 4-42] @ Air cleaner @ 6 mm hex: bolt Removing the air cleaner Fig. 4-41. 107 4. FRAME the air cleaner connecting band. @ Tool box @ Tool box mounting bolt Removing the tool box from the frame Fig. 4-42. 3. Install the air cleaner case. 4.10 REAR FORK A N D REAR FENDER A. Construction One end of the rear fork is fitted t o a section of the frame and the other end is fitted t o the frame through the rear cushion. When the rear wheel bounces, the section which is fitted t o the frame becomes the pivot a x i i and the rear wheel moves i n an arc. The close proximity of the pivot axis t o the drive sprocket po;es negligible change t o the chain tension. (Fig. 4-43) 0 O - Rear cushion under rubber bushins @ Rear fork pivot bushing @ Rear brake stopper arm Fia. 4-43. Rear fork B. Disassembly 1. Remove the rear wheel i n accordance with section 4.13B. 2. Remove the 6 X 12 bolts and 6 x 2 0 bolt t o separate the chain case from the frame. 3. Remove the rear cushions i n accordance with section 4.1 1B. @ Rear fork Removing the rear fork Fig. 4-44. 4. Remove the axle nut and pull out the rear fork pivot bolt. (Fig. 4-44) 5. Drive out the rear fork center collar and the rear fork pivot bushing. (Fig. 4-45) and rear fender setting 6. Loosen the t w o 6 X 12 bolts @ t o separate the rear fender from the frame. (Fig. 4-46) 4.7 0 C. 108 REAR CUSHION Inspection 1. Rear fork center collar ltem / I - Standard Value 14.01 14.02 mm 15.51 6-5.51 9 in) Bore / i Serviceable Limit Replace if over 14.2 mm 10.559 in) 2. Rear fork pivot bolt Outside Standard Value 13.925-13.968 mm Bend 0.02 Max 10.008 in) 3. Rear fork Item Twist Serviceable Limit - / Replace if over 0.05 mm 10.002 in) / Serviceable Limit / - (Fig. 4-47) / / 0.1 Standard Value Max 10.004 in) 0 Plastic hammer @ Driver @ Rear fork Removing the rear fork pivot bushing Fig. 4-45. (Note) Measurement should be made with the rear fork pivot bushing and the center collar assembled in the rear fork. 4. Inspect the rear fender and drive chain case for dents and other defects. 5. Check the drive chain for stretch. 0. Reassembly 1. Install the rear fender. 2. Drive in the pivot bushing, and the center collar, @ 6 X 12 mm hex. bolt @ Rear fender setting bolt Disassembly of the rear fender Fig. 4-46. 0 Magnetic V block @ Rear fork @ Bar for measurtng @ V-block @ Height gauge Fig. 4-47. Measurement of the rear fork Fig. 4-48. Installation of the chain case 4. 4.1 1 FRAME REAR CUSHlON A. Construction The rear cushion is of a bottom link type utilizing the spring to absorb the compressive load, and with an oil damper taking up the reacting load to perform the damping function. The damper contains 52 cc of #60 spindle oil. Improper amount of oil will reduce the cushioning stroke. and result in oil leaks a j well as noise caused by the bottoming piston. @ @ Rear cushion upper rubber bush @ Rear cushion spring seat stopper @ Rear damper piston rod complete @ Staking Cover tube @ Rear cushion upper case @ Rear cushion bottom case @ Rear cushion spring @ Spring under seat @ Rear damper cylinder @ Rear damper case complete Fig. 4-49-1. Sectional view of rear cushion (CB1251 @ @ @ Rear cushion upper rubber bush @ Rear cushion spring seat stopper @ Rear damper piston rod complete Rear cushion upper case @ Staking @ Cover tube @ Rear cushion bottom case @ Rear cushion spring Spring under seat @ Rear damper cylinder @ Rear damper case complete Fig. 4-49-2. Sectional view of rear cushion iCL125) 1st set 173.5(6.831in) &I set 169.36(6.668in> 6 3rd at 165.22 1st set 363 (11.921) 2nd set 30886(11.963in) 3rd set 304.72(11.997in) -I Q Rear cushion spring seat stopper @ Rear damper p i s t ~ nrod complete @ Rear cushion upper case @ staking @ Cover tube @ Rear cushion bottom case @ Rear cushion spring @ Spring under seat @ Rear damper cylinder @ Rear damper case complete Fig. 4-49-3. Sectional view of rear cushion fCB125) @ Rear cushion upper rubber bushing 4.7 7 1st set I Fig. 4-49-4. B. 173.5(6.831in) 2nd set 169.3M6.668in) 3rd set 165.22(6.595in) FRONT WHEEL 7 70 1st set 303 (11.929in) 2nd set 303.86(11.%2in) 3rd set 304.72(11.997in) Sectional view of rear cushion lCL175) Disassembly 1. Loosen the 10 mm blind nut and rear cushion lower bolt, remove the rear cushion assembly. 2. Compress the rear cushion upper case, using the rear cushion disassembly and assembly tool (Tool No. 07035-21601), remove the rear cushion seat, lift off the upper case and then remove the rear cushion spring. (Fig. 4-50.) C. Inspection 1. Rear cushion spring Model CB125 CL125 CB175 75 Standard Value 195.6 mm Free length 17.701 in, 103.6 mm/150 kg (4.079in/330.751bs: within 1.5' Tilt 194.0 mm Free length (7,638 in) 103.6 mm/160 kg , Loading 14.079in/352.8Ibsl Tilt within 1.5O Item Serviceable Limit Replace if under 175 mm (6.890 in1 @ Rear cushion spr~ngseat stopper @ Rear cushion disassembly. & assembly tool @ Rear cushion assembly Disassembling the rear cushion Fig. 4-50. Replace if under 174 mm (6.850 in1 2. Damping Performance : 6 5 k g k 1O%/0.5 m/sec (143 I b s k 1O%/l9.7 in/sec) 3. lnspect for cushion oil leak. 4. lnspect for damage t o the cushion spring seat. D. Reassembly Perform the reassembly in the reverse order of disassembly. (Note) a. The spring i s made with two different types of pitch. the end with the smaller pitch must be toward the bottom. b. To facilitate the installation of the spring seat stopper, extend the cushion until the stopper can be inserted. I k @) Rear cushion spring seat stopper @ Reor cushion spring @ Rear damper case @ Rear cushion upper case @ Rear cushion bottom case @ Rear cushion upper rubber bush @ Rear cushion under bolt @ 1Omm washer @ 1Omm biind nut Fig. 4-51. Rear cushion 4. 4.1 2 FRAME FRONT WHEEL A. Construction The aluminum hub contains the brake assembly, front axle distance collar and bearing enclosed by the brake panel. The slot on the broke panel fits the cushion to prevent the panel from rotating. Axle nut Q Front wheel side collar @ 26427 oil seal @ 6302 R ball bearing @ Front wheel nub Front axle distance collar @ 6302 R ball bearing. @ # 9-157.5 spoke B. @ # 9-158 spoke B. @ Front wheel rim Tire flap @ Front wheel tube @ 2.OX 18 cotter pin @ Anchor pin washer @ Front brake shoe Front brake spring @ Front brake cam @ 54667 oil seal @ Speedometer gear @ Front brake cam Front brake panel @ Front brake cam dust seal @ Front brake arm return spring @ Front wheel tire 8 x 2 8 hex. bolt. @ 8.2mm tongued washer B. @ Front brake stopper arm @ Front brake stopper arm collar @J 8.2mm tongued washer A @ Front brake stopper arm bolt @ Speedometer inner cable @ Speedometer cable @ 5 x 2 0 cross screw @ 6mm hex nut @ Front brake arm B @ 6mm flat washer @ 6 x 3 2 hex bolt @ Front brake arm A @ Front wheel axle Fig. 4-52-1. Front wheel @ @ @ @ @ @ B. Disassembly 1. Place a suitable support block under the engine to raise the front wheel off the ground. Disconnect the brake cable. Remove the 5mm screw and the speedometer cable from the gear box. Straighten the tab of the 8.2 mm tongued washer A and loosen the front brake stopper arm bolt at the front brake stopper arm. Loosen the front wheel axle nut and the wheel will drop off when the axle is drawn out. Remove the panel from the front wheel, two 6302 R ball bearings, and the front axle distance collar. Remove the two 2 X 18 cotter pins and anchor pin washer to remove the brake shoe from the panel. (Fig. 4-52-21 @ Brake shoe @ 2.OX 18 cotter pin 8. Separate the tire and tube from the rim with a Anchor pin wisher tire lever. Fig. 4-52-2. Removing the brake shoe 6 4.7 1 FRONT WHEEL C. Inspection 1. Rim runout. Side (Fig. 4-53) Serviceable Limit Replace or repair i f over 0.5 mm Max Replace or repair if aver 3.0 mm (0.1 18 in) 2. A x l e b e n d a n d wear. Item Outside diameter I Bend (Fig. 4-54) I Standard Value 14.957- 14.984 mm (0.598-0.599 in) 0.01 Max (0.0004 in) Serviceable Limit Replace if under 14.95 mm (0.588 in) Replace if over 0.1 5 mm (0.0059 in) Fig. 4-53. Measurement of deflection 3. 6302 Z ball bearings axial a n d radial clearance. ltem Axial clearance Radial clearance / / Standard Valve 0.05 mm Max 10.002 in) 0.002-0.007 mm (0.0008-0.0014 in) I I Serviceable Limit Replace if over 0.1 mm (0.004 in) Replace if over 0.05 mm 10.002 in) 4. Brake shoe spring f r e e length a n d tension. Standard Value Tension Serviceable Limit :ti Free .length 1 I 57 mm/8 kg 12.215 i n / l l . 6 bs) 1 5. Front brake shoe diameter and lining thickness. e m Diameter Lining thikness Standard Value 158-160 mm (6.22-6.30 in) 5.0-5.3 mm 10.1 97-0.209 @ Dial gauge @ Gauge stand @ V block @ Front wheel axle Measuring the front axle bend Fig. 4-54. in) 6. Front broke cam thickness. Thickness Serviceable Limit 8 mm 10.31 5 in) 1 Serviceable Limit I 7. Inspect and tighten and loose spokes. 8. Check f o r a i r leak b y inflating the t u b e a n d placing i t i n water. 9. Check the tire f o r damage t o casing. @ Tire lever Fig. 4-55. @ Front wheel tire Installing the tire @ Front wheel rim D. Reassembly 1. The tube can b e easily mounted b y inflating w i t h small amount o f air t o make the tube firm. (Fig. 4-55) (Note) (01 After the tire is mounted, inflate with approximately designated pressure a n d lightly t a p a r o u n d the tire w i t h a w o o d e n hammer t o eliminate any pinching o f the tube. (Fig. 4-56) @ Hammer @ Front wheel tire Fig. 4-56. Tapping tire circumference lightly (bl The valve stem should be placed pointing toward the axle t o prevent damage to the tube. (Fig. 4-57) @ Valve stem @ Center line Fig. 4-57. Angle of valve stem Front wheel 2. Grease the 6302R ball bearing and pack the inside of the front wheel hub with grease, and insert the distance collar. Drive in the 6302R ball bearing. (Fig. 4-58) (Note) The 6302R ball bearing incorporates a seal on the outside; therkfore, make sure that the bearing i s not inverted. @ Hornmcr Fig. 4-58. @ Beariflg installing tool Installing the bearing 3. Hook the spring on the front brake shoe and install the two anchor pins and brake cams. Install the unit to the front brake panel and tighten with the anchor pin washer and 2 X 18 cotter pin. 4. Assemble the panel to the front wheel and the gear box t o the bearing retainer side. Secure them by the front wheel axle to the front fork. (Note) The gear box joint section should be in line with the axles of the front and rear wheels. If not, the speedometer cable may break due t o excessive bending. 5. Install the front brake stgpper arm on the front brake panel. 6. Connect the speedometer cable to the gear box. @ Adjusting nut @ Lock nut Adjustment of the front broke Fig. 4-59-1. @ Front brake upper adjuster @ Lock nut Adjustment of the front brake Fig. 4-59-2. 7. Connect the front brake cable to the brake arm and adiust the free fravel. The designated free travel is 10-20 mm 10.4-0.8 in1 4.7 7 4.1 3 FRONT WHEEL REAR WHEEL A. Description The rear wheel consists of the 6303R ball bearings, ICB/CL125 630217 ball bearings) aluminum cast rear wheel hub with the brake drum and brake panel. It contains a single cam mounted in the brake panel. At the left side of the wheel hub, the final driven sprocket is mounted. @ Rear wheel axle @ Drive chain adluster @ Rear brake panel side collar @ 6 mm hex. nut @ Drive chain adlusting bolt @ 6 mm flat waiher @ Rear brake arm @ 6 x 2 0 hex. bolt @ Rear brake panel @ Rear brake shoe @ Brake shoe spring @ Brake cam dust seal @ Rear brake cam @ 630211 ball bearing @ Handle holder setting washer A @ 2.OX 18 cotter pin @ Rear wheel hub @ Rear axle distance collar @ Bft9X162.5 spoke @ Bft9Xl63.5 spoke @ Rear wheel rim @ Tire flap @ Rear wheel tube @ Rear wheel tire @I 630211 ball bearing @ Rear wheel damper bushing @ 28427 oil seal @ Rear wheel side collar @ Final driven sprocket @ 58 mm cir-clip @ Axle nut Fig. 4-60-1. CB/CL125, CB/CL175 Rear wheel 9 75 4. F R A M E ($ Rear wheel axle @ Drive chain adluster @ 6 mm hex nut @Chain adjust bolt @ Rear brake panel side collar @ 6 x 2 0 hex bolt @ Rear brake arm @ Rear brake cam @ Rear brake panel @ Rear brake shoe @ Brake shoe spring @ 6302 Z ball bearing @ Rear wheel hub @ Rear axle distance collar @ Rear wheel damper bush @ 28427 oil-seal @ Rear wheel dust seal @ Rear wheel side collar @ Final driven sprocket @ 58 rnm circlip @ Rear axle nut @ Driven sprocket fixing bolt @ 8 mm tongued washer @ 8 rnm thin washer CB/CL175 Rear wheel (Early model) Fig. 4-60-2. @ Drive chain @ Drive chain clip Fig. 4-61. Removing the drive chain 4.7 3 7 16 REAR WHEEL 5. Remove the 58 mm circlip using a plier ; the final driven sprocket can be removed from the rear wheel. The sprocket on the earlier models is fixed with 4 nuts and locked with tongued washers in addition t o the circlip. 6. Remove the oil seal internal retainer, two 63031 ball bearings, and the rear axle distance collars. 7. The rear brake shoe can be removed from the rear brake panel by spreading the shoes apart by hand. (Fig. 4-63) 8. Use the tire lever to remove the tire and tube. O - Rear wheel Fig. 4-62-1. C. Removing the rear wheel tnspection 1. Rim runout. e m Side runout Vertical runout (Fia. 4-64) Standard a 0.5 mm Max (0.02 in) 0.5 mm Max (0.02 inr 2. Axle bend and wear. Serviceable Limit Replace or repair if over 3.0 mm 10.1 18 in) Replace or repair i f over 3.0 mm 10.1 18 in) (Fig. 4-65) ltem 0.01 mm Max. (0.0004 in1 Bend Replace i f over 0.2 mm 10.008 in1 @ Removing the rear wheel Rear wheel Fig. 4-62-2. 3. Rear brake shoe spring. 4. Rear brake shoe diameter and lining thickness. IFia. 4-66) . - iTi- ltem ICBI 25 1 Standard Value 129.8- 130 mm CL125 15.1 10-5.1 18 in1 Diameter CB175 139.8- 140 mm CLI 75 15.504-5.512 in) CB125 4.0-4.3 mm Lining C L E (0.157-0.1 69 in) thickness C8175 4.5-4.8 mm CL175 10.177-0.189 in) 1 1 @ Rear brake shoes @ Rear brake panel Removing the brake shoes Fig. 4-63. Fig. 4-64. Runout of the rim RAME 5. Inspect and tighten all loose spokes. 6. Inspect air leak by inflating the tube and placing it in water. 7. Check the tire for damage t o casing. D. Reassembly 1. The tube can be easily mounted by inflating with small amount of air t o make the tube firm. (Note) @ RearI wheel axle Fia. 4-65. Measurina of rear wheel axle bend a. After the tire is mounted, inflate with approximately the designated pressure and lightly tap around the tire with a wooden hammer to eliminate any pinching of the tube. b. The valve stem should be pointed toward the axle. 2. Grease the 6303R (CB125/CL125 : 630213 ball bearing and pack the rear wheel hub with grease. Insert the spacer and d r ~ v ethe 6303R (CB125/ CL125 : 6302R3 bearing into place. (Fig. 4-68) (Note) The 630311 (6302R1 ball bearing incorporates a seal on one side, therefore, make sure that the bearing i s not inverted. @ Vernier caliper @ Brake shoe Fig. 4-66. Measuring the brake shoes @ W o o d spreader Fig. 4-67. @ Rear tire Tire inspection @ Rear wheel rim @ Plastic hammer (3 Bearing installing tool Driving the ball becring Fig. 4-68. 4.13 7. Adjust the drive chain. (Note) REAR WHEEL @ 8mm thin nut @ 8 rnm tongued washer @ Final driven sprocket Fia. 4-69-1. Tightening the final driven sprocket @ 58 mm circlip @ Final driven sprocket Fig. 4-69-2, Installing the final driven sprocket @ Rear brake arm @ Rear brake panel Fig. 4-70. Installing the rear brake arm MEMO 5.7 IGNlnON CIRCUIT I20 5. ELECTRIC SYSTEM These models use essentially the same basic electrical system with a varying degree of minor differences. The electrical equipment and their installation depend upor, the wiring circuitry. The ignition system is comprised of a special A.C. generator with the use of an ignition coil and contact breaker t o provide easy starting. The charging and power supply t o the electrical system is previded by the combination of A.G. generator and selenium rectifier t o take care of the discharge load such as the horn, lights and the indicator lamps. The function of the electrical system can be classified as follows: (Fig. 5-1) @ Spark plug @ lgnition coil @ Selenium rectifier @ Contact breaker @ A.C. generator @ Battery O Switch 1. lgnition system (ignition coil, condenser, contact breaker and spark plug) 2. Generating system (A.C. generator) 3. Rect~fyingsystem (selenium rectifier) 4. Battery 5. Various loads (lights and horn1 1. IGNITION CIRCUIT A. lgnition Coil (Fig. 5-2) The ignition coil is made up of a primary coil which comprises o f approximately 500. t o 300 turns of 0.6 mm (0.024 in.) enameled copper wire wound over an iron core, and a secondary coil of 10,000 t o 20,000 turns of 0.075 mm (0.003in) enameled copper wire. Coil is coated with dielectric material and molded in a synthetic compound, with two exposed terminals. (Fig. 5-2, 3) ($ lgnition coil Fig. 5-2. lgnition coil i I CB/CL175 (Specification) Primary Current : 12V, 3.2A max. under locked condition at normal temperature. 12V, 0.6A max at 10,000 rpm crankshaft. ... Spark Characteristics : Length, 7mm min. ...p rimary 8V, 300 rpm crankshaft. Length, 7mm min. ...p rimary 12V, 10,000 rpm crankshaft. Cam closing angle shall be at 180' of crankshaft. Measurement shall be made with a gap of lmm o n one side of the high tension lead, the other lead shall be connected t o the three point spark gap tester. The measurement shall be taken of the gap between the points of the three point tester. CB/CL125 (Specification) Primary Current: 6V, 4.3A max. under locked condition at normal temperature. Spark Characteristics : Length, 8mm min. ...p rimary 5V, 300 rpm crankshaft. Length, 8mm min. ...p rimary 7V, 10,000 rpm crankshaft. 8. Spark Advancer lgnition timing is automatically advanced with the increase in engine RPM. The device which performs this function is the automatic spark advancer. It, utilizes the centrifugal force of a rotating mass t o actuate a cam which controls the opening of the breaker points. (Fig. 5-41 I @ lgnition coil Low tension lead 4 mm inner cord connector @@ High tension cord Fig. 5-3. lgnition coil assy. I 5. ELECTRIC SYSTEM The spark advancer, mounted on the left end of the camshaft for the CB/CL175 model and mounted against the A.C. dynamo rotor for the CB/CL125, is held in a fixed position, at 5O advance, by a spring. As the engine speed increases, the revolving weights on the advancer moves outward by centrifugal force, overriding the force of the spring to move the cam in the direction to cause an early ignition. The spark advancer starts to become active at the engine speed of 900 RPM (CB/CL125 : 1800 RPM) and advances 40' at 3,900 RPM (CB/CL125: 3200 RPM!. (Fig. 5-5) Fig. 5-4. Spark advancer C. Contact Breaker Contact breaker is a device which performs a very important function of interrupting the primary circuit of the ignition coil to enable the build-up of the high secondary voltage. It is composed or the breaker arm, stationary and movable points, primary terminal, breaker arm spring and oil felt, all of which are assembled on the base plate and mounted together with the spark advancer. The breaker arm i s a formed sheet metal piece with a bakelite cam follower attached to one end. It must operate very lightly and, further, in order to minimize the inertia, the arm must be light and strong. (Fig. 5-6, 5-7) @ 5" advanced angle @ Contact breaker arm Fig. 5-6. Breaker points @ 40' advanced angle @ Breaker points The movable point requires a strong spring tention to prevent chattering during the collapse of the primary circuit. however. on the other hand. the tension must Inspection 1. Make sure that the points are free of oil. a. Points become black and result in excessive wear, if dirty. b. If left uncleaned for a long time, a hardened oil insulation film will result and causes faulty ignition. 2. Breaker arm with excessively worn pivot hole should be replaced. 3. Make sure that the insulation at the contact breaker terminal i s free of oil, water and dirt. Fig. 5-7. Contact breaker assembly 4. Pitted or dirty points should be cleaned with a point file or sandpaper. Points with excessively pitted surfaces should be removed and both surfaces dressed so that the points are making parallel contact. D. Condenser The purpose of the condenser is to prevent unwanted sparking across the points, however, if the condenser capacity i s too large, the ignition spark will deteriorate, normal value is 0.3pf, f10%. At the instance of point opening, the condenser will have several hundred volts applied momentarily, therefore, it must have sufficient capacity to withstand this surge. (Fig. 5-8) After performing a leak test on the megger, a simple capacity test of the condenser can be made by removing the terminals from the megger while still in operation and use a wire to short across the terminals. If there i s a good strong spark, the condenser can be assumed t o be in good condition. Actually, the capacity of the condenser will not change. A use of a service tester will provide an accurate measurement of the capacity and resistance values. E. Fia. 5-8. Condenser Fig. 5-9. Spark plug Spark Plug Spark plug performs one of the most important functions in the engine ignition system. The high voltage produced by the ignition coil is received by the spark plug and produces the high tension spark as it jump across from the center electrode of the spark plug to the side electrode. The spark ignites the compressed fuel mixture in the combustion chamber and causes an explosion which operates the engine. Even under various adverse conditions, durability and reliability is required. (Fig. 5-9) 1 . Spark Plug Condition The operation of the engine by the condition of the plug. the insulator colored white, indicates good condition and factory. can be determined The firing area of gray o r light gray is performing satis- 2. Heat Range The firing area of the spark plug insulator is exposed to carbon and oil while the engine is operating, and to prevent its build-up, plugs are designed to burn off any deposits by the heat of combustion. In order t o function as above, the surface of the insulator firing area must be maintained at appro(932- 1,60O0FI range. This ximately 500-870°C temperature is referred to as the self-cleaning temperature, and will vary to a considerable degree with the type engine and design, riding condition and type fuel used. In order for the plug t o function properly under the different conditions it is necessary for it t o dissipate the heat caused by the combustion. 5. ELECTRIC SYSTEM The rate of heat dissipation of the plug in determined by the heat range of the plug. A plug which readily dissipates the heat and which is difficult t o overheat is referred to as a "Cold Type". A plug which retains the heat and which will burn readily is referred t o as a "Hot Type". O n engine operating at high temperature, a plug which is difficult to overheat, in other words, the cold type plug is used and for engine operating at low temperature a hot type plug is used. (Fig. 5-10) 3. Spark Plug Reoch I @ Hot type @ Medium type @ Cold type Fig. 5-10. Sectional view of the spark plug The reach of the spark plug refers t o length of the threaded section. Different model motorcycles have cylinder head designed with different depth of spark plug hole, therefore, the spark plug with the proper reach should be used. (Fig. 5-11) Reach : 12.7 mm. The following unsatisfactory conditions will occur if plug of improper reach is used. ( 1 ) Reach too long a. Carbon will be deposited on the exposed thread and cause damages to the threads in the spark plug hole during plug removal. b. The plug tip will become overheated, causing pre-ignition. @ Reoch Fig. 5-1 1. 4. (21 Reach too short a. Carbon will be deposited on the threads at the bottom of the plug hole and when the spark plug of the proper reach is installed, the threads will be damaged or stripped. b. Due to the cavity left by the short reach, exhaust gas will accumulate causing a decrease in power output. overheating and engine malfunction. Spark plug reach Spark Plug Gap The spark plug firing, regardless of whether the primary power supply is from an A.C. generator or a D.C. source, is produced by the high voltage secondary coil. The voltage generated will vary with the engine speed, however, with the proper spark gap, there is always sufficient voltage to produce a spark required for the ignition of the compressed fuel mixture. If the spark gap is too wide, a very high voltage i s necessary t o produce the necessary spark and, in which case, a misfire will result at low speed. O n the otner hand, if the gap is too narrow, a spark will be produced at a very low voltage and being of a low energy, an incomplete explosion will take place, resulting in engine malfunction. 5. Main Spark Plug Trouble and Corrective Action. a. Poor starting, occasional misfire, knocks during acceleration. b. Malfunctions when climbing, backfires, preignition. 5. MAIN SPARK PLUG TROUBLE AND CORRECTIVE ACTION A. Poor starting, occasional misfire, knocks during acceleration. Symptom 1. Dirty plug electrodes (sooty) 2. Plug wet with fuel 3. Flushed over Corrective action Probable cause Misfire caused by the insulation of the electrodes due to carbon deposits or fouling with oil. 1. Too rich a fuel mixture. 2. Excessive intake of fuel during starting. 3. Heavy carbon deposit on the electrode resulting in bridging or narrowed gap. 1. Adjust the spark gap, adjust carburetor. 2. Dry the plugs, change the procedure on the use of choke. 3. Clean and properly adjust the gap. Standard gap : 0.6-0.7 mm (0.024-0.028 in) 5.2 ELECTRICAL POWER SUPPLY B. Malfunctions when climbing, backfires, pre-ignition. 1. Electrodes not noticeable dirty. 2. Electrodes excessively eroded. 3. Small deposits on the insulator. 4. Indication of burning. F. Corrective action Probable cause Symptom 1. Replace plug gasket or retwque Spark plug 1. Insufficiently torqued causing exhaust gas lead. 2. Too lean a fuel mixture. 3. Ignition timing too for advanced. 4. Improper plug, head range too low. the plug. 2. Adjust the carburetor. 3. Adiust ignition timing. 4. Replace with plug of higher heat range. (higher numbered plug) Noise Suppressor The oscillating current which contains the high frequency radio wave produced by the high tension ignition circuit is radiated from the high tension circuit and the vehicle chassis t o cause interference to the reception of the radio and television sets. To prevent this undesirable condition, the spark plug is fitted with a suppressor. The suppressor consists of a resistor incorporated within the plug cap and housed in the shield cover. The resistor functions as a diminishing resistor, the shield cover increases the high frequency suppressing characteristics as a combined part of the suppressor. (Caution) 1. The suppressor should be handled in the same manner as the plug cap, however, provide adequate care t o the junction of the high tension cord and make sure that the cord is fully screwed in. 2. If the resistance value should accidentall./ change or if the value should become infinate, it should not effect the performance; (discoloration of the outer insulated coating) it i s recommended, however, that it be changed with a new item. 2. ELECTRICAL POWER SUPPLY A. A.C. Generator (Fig. 5-12) A generator produces electricity because. an iron core cuts across a magnetic field. This basic principle holds true both in the flywheel magneto, D.C. Generator or an A.C. generator. In the A.C. generator, the output voltage changes direction, henceforth the name A.C. (alternating current) generator. The advantage of an A.C. generator is that the malfunction as *compared t o the other type is less frequent due t o its simpler construction and fewer parts which are subject t o wear. Another major advantage is that the kick starter can be employed as an auxiliary starting method even with the battery completely discharged. This is because the A.C. generator induces a large voltage which when fed through the rectifier t o the ignition coil will produce a spark o f sufficient strength to produce ignition. Fig. 5-q2A. A'C' generator @ Stator @ Rotor @ Washer @ Set bolt Fig. 5-128. A.C. generator construction 5. ELECTRIC SYSTEM 8. Characteristics I I RPM CB/CL125 CB/CL175 Items I 300-1 1,000 RPM 300-1 0,500 RPM I I Normal voltage Electrical lood Charging *Initial charging speed *Charging at 5000 RPM After full wave rectification. Day : 6V-12AH battery+ ignition coil (single lobe cam with spark every revolution, contact breaker closed 180" of each revolution1 Night : In addition to the day lood, the lamp loads are added (H.L. 35W, T.L. 8W, M:L. 3WX3, B.L. 2.5Wl After full wave rectification. Day : 6V-6AH fignition coil (D.C. ignition, spark every revolution, contact breaker closed 180' of each revolution1 Night : In addition to the day load, the lamp loads are added (H.L. 25W, T.L. 5W, M.L. 3Wl Day : Night: Day : Night : Day : 1300 RPM max Night: 2000 RPM max 2400 RPM max 2800 RPM max 1.0+0.5A 1.0+0.5A Night : +0.5A 2.0 -0.3A 3. SELENIUM RECTIFIER A rectifier is an equipment which converts the A.C. (alternating) current to a D.C. (direct) current and is necessary for use with an A.C. generator or an A.C. generating coil. Battery requires D.C. voltage for charging and if the electrical voltage produced by the generator is an A.C., this must be converted to D.C. so that the battery can receive the charge. @ Rectifier Fig. 5-13. Selenium rectifier construction diagrm Fig. 5-14. Selenium rectifier Rectification is a process of causing the cyclic reversing current to flow in only one direction. As shown in the figure, it permits the current to flow in one direction but blocks the current from flowing in the opposite direction, thus i s known as a half wave rectification @. There is another type which changes the reverse flow of current so that if also flows in the same direction; this is known as full wave As shown in the figure, the cuirent will readily flow in the normal direction and only a negligible amount flows in the opposite direction. When this unit i s placed in the primary A.C. circuit, the current will flow in only the specified direction form the output side. (Fig. 5-14) I I 5.3 SELENIUM RECTIFIER A. 5.4 BATTERY Selenium Rectifier Installation a n d Handling 1. Do not bend, cut or scratch the selenium wafers. 2. The rectifier locking nut should not be loosend or the wafers rotated. Any movement will cause the electrode alloy to peel, affecting the rectification function further, it will destroy the moisture proofing and thereby, shortens the life of selenium rectifier. 3. Take adequate precaution not to permit rain, salt water, water or battery electrolyte to get on the selenium rectifier, as it will cause the amount of current flowing in the reverse direction to increase. Further, i f the selenium wafer if exposed to moisture for any length of time, oxide will be produce on the surface, resulting in a shorted condition and the following trouble will occur. a, Battery will be discharge. b. Malfunction of the charging system. 4. DO m t operate engine without the battery or electrical load connected to the circuit. a. Loose or disconnected lead at the battery terminal. b. Loose or disconnected terminals on the lead between the battery and the @ side of the selenium rectifier. c. Running without a battery. If the engine should be started under the above condition or if such condition should develop while the engine is being operated, a high voltage will be produced due to the absence of any load on the coil, and this high voltage will cause a large amout of current to flow through the rectifier in the reverse direction, resulting in the eventual damage to the selenium rectifier. Therefore : a. Always maintain all electrical connections in the circuit in a good condition. b. Under no circumstances should the engine be started without the battery connected. 4. BATTERY A. Construction The battery stores the electricity produced by the generator for use as a source of power for the safety items such as the lights and horn. At present, all batteries used for small type vehicles are of a lead storage type inclosed in a plastic case. The construction and the name of the component parts are shown in (Fig. 5-15). @ Pole @ Q terminal @ Negative plate @ Separator &.glass net @ Container @ @ terminal @ Positive plate Fig. 5-15. Battery construction B. RATING Type Voltage Capacity Specific gravity of electrolyte MBW3-12C 12 V 9 AH 1.260-1.280 at 20°C 168OF) 836-6 6 V 6AH Same as left 5. ELECTRIC SYSTEM C. Instruction on use and Servicing 1. Check specific gravity Before using the battery, check the capacity and if the specific gravity of the electrolyte is below 1.220 at 20°C (68OF) (less than 75% capacity), the battery should be recharged. (Note) The relation between the battery capacity and the specific gravity (residual capacity) is shown in (Fig. 5-16). When the specific gravity is 1.189 at 20°C (68OF1 (less than 50% capacity) the residual capacity is small and if continued t o be used in such a condition, it will eventually lead t o trouble as well as shortening the battery life, therefore, the battery should, under such a condition, be recharged as soon as possible. (Fig. 5-1 6) @ Specific grovity I2O0C) @ Residuol copocity 1%) Specific grovity ond residual copocity chart Fig. 5-16. Inspecting the electrolyte level. As shown in Fig. 5-17, if the electrolyte level falls below the LOWER LEVEL, remove the filler cap with a screw driver or an appropriate tool and fill the battery t o the UPPER LEVEL with distilled water or battery water. Do not fill beyond the UPPER LEVEL. (Fig. 5-17) @ Upper level mork Fig. 5-17. Whenever the vent pipe is removed during recharging, it must be reconnected when the battery is installed. Care should be exersized not t o restrict the opening. @ Lower level mark D. BATTERY CHARGING PROCEDURE 1. Connection to Charger (Fig. 5-18) Connect the positive ($1 terminal of the battery (colored red) t o the positive terminal of the charger, and the negative (-1 battery terminal t o the negative terminal of the charger. (Fig. 5-18Al When more than one battery is t o be charged a? once, they should be charged in series, as shown in (Fig. 5-18B). Series Connection for Multiple Charging Fig. 5-18A. @ Charger @ Battery - Fig. 5-188. (Note) When series charging more than one battery, the charger voltage must be the sum of the battery voltages. For example, t o charge three six volt batteries, the charger must have an output voltage in excess of 6+6+6 or 18 volts. 5.4 BATTERY 2. Charging Charge the battery at the current specified in following table. Voltage IV) Type MBW3-12C (Used on CB/CL175) Electrolyte Volume of Specific electrolyte gravity re'quired at 20° for filling 1680F) (liters) Capacity atl0-hr rate (AH) Charging 9 0.9 1.260 0.7 1.280 6 0.6 1.260 0.26 1.280 12 836-6 (Used on CB/CL125) current (A) Specific gravity of electrolyte when fully charged at 20°C 168°F) The charging time for a new battery is determined by the length of time in storage since the date of manufacture. (Date of manufacture is printed on the back of the specification booklet, enclosed with motorcycle batteries). The table shows the approximates charging times. Duration of storage Less than 6 months. 6 to 12 months. Over 12 months. Duration of charge 10 to 20 hrs. 20 to 30 hrs. Over 30 hrs. (Note) 1. During the charging operation, if the battery temperature exceeds 45OC (113OF), discontinue charging or decrease charging current to 1/2 of the specified value until the temperature falls t o a safe level. In this case, charging time must be increased. 2. Be sure to charge tbe battery at the specified current. 3. If the electrolyte level falls during charging, refill with distilled water to the upper level line (to the level indicator in hard rubber-caie batteries). Near the end of the charging period, adjust the specific gravity t o between 1.270 and 1.290 (between 1.250 and 1.270 in tropical areas), and continue charging for two t o three additional hours. 4. Explosive hydrogen gas is discharged from the cells, therefore, do not charge batteries near any open fire. Always turn charger off before connecting or disconnecting batteries. 5. After charging, add distilled or battery water to the cells to bring the electrolyte to the upper level line (to the level indicator in hard rubber case batteries). Tighten cell caps firmly and wash off with clean water any acid spilled. 6. Thk battery is now ready to install. Whhn installing a motorcycle battery, be sure not pinch the battery vent tube. Explosion may result if the exhaust tube is blocked. 3. Preventative Maintenance The battery i s being recharged all the while the engine is running. Further, while running, the load such as the use of the winker, horn are placed on the battery idischargad), as the result, the battery is being discharged at the same time it is being recharged. In the long run, the discharge and the recharge is in balance. The system has been designed in this manner. develops. Under certain condition when the balance is upset, then trouble To obtain maximum life from the battery, it is necessary to locate this trouble and take the appropriate action early. The trouble to the battery are mainly external such as cracked case, broken terminal, disconnected lead wire. The battery condition, trouble, corrective action are shown in the following table. 729 5. ELECTRIC SYSTEM E. TROUBLE SHOOTING AND CORRECTIVE ACTION Probable cause Correct action 1. Charging rate is too small or else excessively large. The specific gravity or the mixture of the electrolyte is improper. Battery left in a discharged condition for a long period. (left with the switch turned on). Exposed to excessive vibration due to improper insulation. Motorcycle stored during cold season with battery connected. 1. When motorcycle is in storage, the battery should be recharged once a monih even though the motorcycle is not used. 2. Check the electrolyte periodically and always maintain the proper level. 3. In a lightly discharged condition, performing recharging and discharging several times by starting the engine may be sufficient. B. Self discharge Battery discharges in addition to that caused by the connected load. 1. Dirty contact areas and case. 2. Contaminated electrolyte or electrolyte excessively concentrated. 2. Handle the replenishing electrolyte with care. C. Large discharge rate Trouble A. Sulfation The electrode plates are covered with white layer or in spots 2. 3. 4. 5. 1. Always maintain the exterior clean. 1. The fuse and the wiring is satis- 1. When the specific gravity falls Specific gravity, gradually lowers and around 1.100, the winker and horn no longer function. factory, loads such as winker and horn does not function. In this condition the motorcycle will operate but with prolong use, both @ and @ plates will react with the sulfuric acid and form lead sulfide deposits, (sulfation) making ~t impossible to recharge. below 1,200 (20°C : 68OF1, the battery should be recharged immediately. 2. When the battery frequently becomes discharged while operating at normal speed, check the generator for proper output. 3. If the battery discharges under normal charge output, it is an indication of overloading, remove some of the excess load. D. High charging rate The electrolyte level drops rapidly but the charge is always maintained at 100% and the condi!ion appears satisfactory. A condition which is overlooked. (Specific gravity over 1.260) 1. The deposit will heavily accumulate 1. Check to assure proper charging at the bottom and will cause internal shorting and damage the battery. rate. 2. When overcharge condition exist with the proper charging rate, place an appropriate resistor in E. Specific gravity drops 1. Shorted 2. Insufficient charging 3. Distilled water overfilled 4. Contaminated electrolyte Electrolyte evaporates the charging circuit. 1. Perform specific gravity measurement. 2. If the addition of dis:illed water causes a drop in specific gravity, add sulfuric acid and adjust to proper value. 5.5 VARIOUS LOADS 7 30 5. VARIOUS LOADS A. H e a d l i g h t The headlight is t o provide safe riding at night and, therefore, it should always be maintained at proper adjustment. O n the CB/CL175, a sealed beam type lamp unit is used, ,whereas, a semi sealed type is used on the CB/CL125. On these types, deterioration rate of brightness is relatively low. (Fig. 5-19-1-2) a. Malfunctions 1. Broken bulb filament Primary causes are : Excessive voltaae a .~.o l i e d Excessive vibration due to bad roads or high speed riding. Defective material. - @ Head light rim @ Head light unit Component parts of head light (CB/CL 1751 Fig. 5-19-1. 2. Defective contact. Contact points making poor contact B. Taillight, S t o p l i g h t A combination light bulb is used for the taillight and the stoplight. The bulb rating is 6V-18/5w, ICBjCL175 : 6V-25/8W) the stop lamp is 18W ICB/CL175 : 25W) and the tail lamp 5W (CB/CL175 : 8W). The alass enclosure is a pear shaped bulb ICB/CL 12; (Fig. 5-20] b. Inspection @ Head light rim @ Head light bulb @ Head light socket @ Socket supporter @ Boot Component parts of head light ICB/CL 125) Fig. 5-19-2. 1. Broken filament The main cause of broken filament can be attrib*.ted to excessive vibration resulting from riding over bad roads or excessive voltage, howeve, in a rare case it can also be caused by d .fective material used in the manufacture of the bulb. Remedy : Replace the bulb. 2. Defective contact Bulb contacts making poor contact 1 ith the socket. 3. Broken cord Cause : Break at the terminol due to vibration from riding over rough road. Remedy: Peel back the insulation of the cord and resolder the wire to the p oper terminal on the socket or connector. @ Toil light base @ Tail light bulb @ Tail light lens @ 4x45 cross screw Fig. 5-20. Component parts of tail light C. N e u t r a l l a m p a n d Speedometer l a m p This lamp is to indicate the gear change to be in the neutral position and is located within the speedometer. Lamp rating is 6V-3.OW. Refer to section 1.2 for remedy in case of defective operation (Fig. 5-21) @ Neutral lamp bulb @ Socket Fig. 5-21. Components ports of neutral lamp 5. ELECTRlCAL SYSTEM 6. STARTING M O T O R A. Description CB 175 is equipped with a starting motor mounted on the forward section of the crankcase. a kick starter can be used as an auxiliary starting method. In addition When the starter switch is depressed, the powerful series wound electric motor incorporating a planetary reduction gear drives the crankshaft by means of a chain and sprockets. As the engine starts, the speed or the crankshaft exceeds the starting motor, however, the starting motor is presented from being motorized by the overrunning clutch mounted on the driven sprocket. The starter magnetic switch i s installed in the starting circuit to permit a large current to flow to the starter when the starter switch is depressed. S t a r t e r Specification 12V Rated voltage Rated output 0.35 KW Rated loading time 30 sec. Reduction ratio Direction of rotation 5.45 left hand, viewing the sprocket Battery 12V - 9AH Weight 2.5 kg max. Starter Performance at sprocket shaft 1 1 without load with load 9.4V Voltage 11.5V Current 28A max. 1OOA - Torque - Power output 550 Brush spring tension 5.85-5.95mm Brush holder 6.15-6.3X 240A - 1.5kg. m min. - 0.33 KW min. It 55 gr. I Carbon brush 6.7V 500 rpm min. 2000 rpm min. RPM at been locked X 12.2- 12.4mm X 11 - I Clearance, in rotary 12.5mm direction 0.2-0.45mm in axial direction 12.6-12.8 mm 0.2-0.6mm - 7 32 5.6 STARTING MOTOR @ 0 ring @ Sprocket shaft @ Gear cover @ Ring gear @ Planetary gear @ Rubber gasket @ Oillen metal D @ End bracket A @ Drive sprocket @ Oilless metal C @ Oil seal @ Rotor shaft @ Oilless metal A @ Oiliess metal B Construction of starting motor Fig. 5-22. 8. Disassembly a. Removal of starting motor 1. 2. 3. 4. 5. Disconnect the electrical power cable from the starting motor terminal. Remove the two 5 X 12 cross screws and starting motor side cover. Remove left crankcase cover. Remove the starting motor sprocket by removing the starting chain. Remove the three starting motor mounting bolts and separate the motor from the engine. C. Inspection 1. Check the commutator for wear and if necessary, repair. 2. Check wear of the brush, if worn excessively, replace. 3. Check tension of brush spring, if there is loss of tension, replace. 4. Check the reduction gears for wear and damages, replace if necessary. 5. Check the driven sprocket, overrunning clutch spring and roller for wear and damage. Replace any defec- tive parts. 6. Check all ball bearings and bushings for wear and damage, replace if necessary. 7. Check the operation of the starter magnetic switch by applying battery power to the primary terminal while grounding the solenoid body. A click will be heard for a solenoid which is in good condition. If the starting motor does not operate properly, the solenoid contact points may be in poor condition. Disassemble the solenoid and clean the points with a fine file. D. Reassembly Reassemble the starting motor and overrunning clutch in the reverse order of removal. (Note) Apply a thin coaling of silicone grease to the overrunning clutch rollers during assembly. 7 33 5. ELECTRIC SYSTEM 7. SERVICE TESTER INSTRUCTION item I power 1 Direction for I Use Connect the test leads to the " X " terminals and attach the ends of the test leads t o the part to be tested. If there is continuity, the red "Continuity" lamp will be lit. N o lighting indicates that there is no continuity. Examples : 1. Light bulbs, shorted or open elecfllcal circuit. 2. Many other elettrical continuity tests can be performed. @ Continuity lamp @ Power (6V or 12V) @ Continuity @ O N turn the switch off @ Test lead Short out the ends of the test leads connected to the " X " terminals and adjust the indieator needle of tibe resistance meter to " 0 " by the adiusting knob. Attach the ends of the test leads to the points across which the resistance is to be measured and read the meter indication. Examples : 1. Secondary ignition coil, 5,000-10,000 ohm 2. Selenium rectifier normal direction, 5-40 ohm 3. Selenium rectifier reverse direction, 600 ohm min. 4. In addition, measurement of resistance across the points and many other uses. Short out the ends of the test leads connected to the " X " terminals and adjust the indicator needle of the insulation meter to "0"by the adiusting knob. Attach the ends of the test leads across the points to be measured, the insulation value is indicaled on the meter. .#- hl + c .-0 -+ - -+0 VI z 2 5 a Examples : 1. Condenser insulation value : Under 1M ohm. defective Over 5 M ohm satisfactory 2. Various insulation tests may b e performed. @ @ @ @ @ @ @ Black scale Adjusting knob Power (6V or 12Vi Resistance Turn the switch off Test lead Short (Adjust the needle to "0") 0 ,- a @B @-+ 8x0 I%F] 0 , ... .... @ @ @ Black scale Adjusting knob @ Power t6V or 12'4) @ Insulation @ Turn the switch off, discharge after the measurement @ Condenser, Short out the terminals t o discharge @ Over 5 M ohm. ..... satisfactory @ Under 1M ohm. ..... detective @ Condenser 5.7 SERVICE TESTER INSTRUCTION Item I Power .- $ + C >- Xa V k 5 : .- - 1(1 P Direction for 7 34 Use With the initial resistance adiust the indicator needle of the meter to " 0" by the adjusting knob and position the switch to "Condenser". Attach the ends of the test leads t o the test condenser terminals and read the capacity on the meter. Range of measuring value : 0.3-0.3pF C! 2 '0 Q Red scale u @ Adjusting knob @ Power (6V or 12Vl v @ Condenser Q Turn the switch Attach the red test lead from the " X " terminal t o the @ side and the black test lead from the " X " terminal t o the @ side of the test part and read the measurement on the meter. .E E a -0 E u a3 rJJ - -0 .-3E E Examples : 1. Battery terminal voltage 2. Measuring the output of the D.C. dynamo .0 z @ Blue scale @ Battery @ D.C. voltage @ Turn the switch off Connect the D.C. current measuring leads t o the D.C. current terminals. When the current flows from the red terminal t o the black terminal, the indicator needle on the meter swings t o the normal direction. If the indicator needle swings in the reverse direction, the connection at the D. C. connection must be reversed. "Bbfl"H @D @Id (Caution) If the connections are reversed, fuse L15A) will be blown. When the indicator needle o f the meter does not swing, inspect for fuse. Example : 1. The charge or discharge condition o f battery. 2. Measuring the current consump~ion o f flasher, horn, light, etc. the Q Yellow scale Q D.D. cl~rrent the @ Charge @ Discharge Q ?urn thr switch off @ Switc' @ Set-nium rectifier @ Bsittery @ Mounted o n chassis 15A fuse 7 35 ltem 1 5. power .. I ? a I aI -.>0. CI, -tJ .-2 .'. w 3 0 z 1 ELECTRIC SYSTEM Direction @rrli for Use Attach the @ test lead from the " X u terminal to the @ side of the dynamo (A.C.1 either day or night operation and the @ test lead to the @ side or to the chassis and measure the voltage with the engine running. (Caution) Do not run the engine at high speed. Measure at a speed below 2,000 rpm. Y B-- @re \% #a1 -.__ @ @ Blue scale @ A.C. voltage @ Turn the switch off @ Day @ Chassis ..m. 4 ' .- E i= r $ $! Plug in the timing light attachment into the timing receptacle. Next, attach the timing light high tension cord to the hex bar installed on the head of the spark plug. Position the switch to "Timing", start the engine and the timing light will sfart flashing. Point the light to the flywheel adjacent to the case timing index mark. The ignition timing and spark advancing can be inspected. 8 Y~, @ Night @ Dynamo IA.C.1 @ @ @ Earth @ Power 6V or l2V @ Timing @ The switch may be turned either ON or OFF @ Hex bar 6)Engine ‘o Plug cap @ Timing light @ Ignition timing alignment mark @ Rotor Plug the crow foot plug into the crow foot receptacle to connect the primary coil, and connect the red test lead t o the @ side of the primary coil and the white test lead to the @ side. Then, connect the high tension cord from the upper RH corner of the pocket in the tester body to the high tension secondary coil. Position the switch to "Coil Test" and the spark will jump across the three needle test gap. Measure the spark gap by turning the adjustment knob. (Caution) Ground the black cord in the upper LH pocket of the tester body to avoid possible electric shocks during the test. For 6V coils, use 6 volts power and 12 volts power for 12V coils. @ Black @ Ground T@ @ Power (For 6V coils. 0 @ @ @ @ @ @ 0 use 6V power and use 12V power for 12V coils1 Primary coil @ Coil test The switch may be turned either O N or OFF High tension secondary (For simultaneous ignition) Coil @ Primary coil For common use @ Red White @ Normal Reverse 7 36 5.7 SERVICE TESTER INSTRUCTION measurement 2. When the power indicator lamp is not lit with the battery connected, the probable causes o f the trouble are either blown fuse or defective vibrator. Inspect the parts. 3. When using the timing light, if the service tester is operating but the timing light is not lir, the bulb (xenon tube) is probably defective and should be replaced. @ Power indicator MEMO 6.7 MAINTENANCE INSPECTION 6. PERIODIC ADJUSTMENT 6.1 MAINTENANCE INSPECTION Periodic inspections should be performed at regular schedule and designated mileages in order to obtain satisfactory service as well as to extend the useful life of the motorcycle. A. ENGINE ADJUSTMENT 1. MEASURING COMPRESSION A low compression pressure will result in a corresponding drop in the engine power output. Pressure leak from any cause may effect the engine speed adjustment at low speed and create engine stall condition. (5) Compression gauge Fig. 6-1. Measuring compression pressure a. Remove the spark plug. b. Insert the end of the compression gauge into the spark plug hole and hold firmly to prevent pressure from leaking. (Fig. 6-1) c. Operate the kick starter repeatedly several times with both the choke and throttle in the full open position. (Note) 1. Make sure that the throttle and choke are fully open, or else, a lower pressure indication will be registered on the compression gauge. 2. The cylinder compression pressure indication will gradually increase with each kick, therefore, continue kicking until the pressure stabilizes at the highest point. 3. To obtain a true cylinder pressure indication. the measurement should be made after the engine attains operating temperature. 4. Check for the proper operation of the valves. 5. Make sure that the compression gauge i s firmly fitted in the spark plug hole to prevent pressure leak. d. The normal cylinder compression pressure is 10kg/cm2 (142.3 1b/in2). e. In case the compression pressure exceeds 12 kg/cm2 (172 1b/in2), it is an indication of heavy carbon deposit accumulation on the cylinder head or the piston. The deposits should be removed by disassemblying the cylinder head from the cylinder. f. When the compression pressure registers less than 8kg/cm2 ( 1 14 1b/in2), it i s an indication of pressure leok. First check the tappet adjustment and see if the condition can be corrected. disassemble the engine and inspect the condition of the valves, the head gasket and piston rings. 2. TAPPET ADJUSTMENT The tappet clearance will have a great deal of effect on the valve timing. If the clearance is too small, it may prevent the valve from fully closing and result in pressure leok at the valve. O n the other hand, an excessive tappet clearance will produce tappet noise and result in noisy engine operation. The tappet clearance will also have a varying degree of effect on the engine power output, engine operation at slow speed and engine noise. 1. Valve clearance a. Remove the left crankcase cover and align the "T" timing mark on the A.C. generator rotor with the timing index mark on the stator. (Fig. 6-2) b. Unscrew ?he tappet adjusting cap on the cylinder head and check the clearance between the adjusting screw and the valve with a thickness gauge. (Fig. 6-3) 8 Timing index mork @ "T" mark Fig. 6-2. Aligning the "T" mork 7 39 6. PERIODIC b If the valve is being actuated by the rocker arm, rotate the A.C. generator rotor one complete turn to set the piston at top-dead-center of the compression stroke, and then perform the check. 2. Adiustment Loosen the adjusting screw locking nut and make the adiustment with the adiusting screw to obtain the standard clearance of 0.05 mm (0.002 in.) for both the inlet and exhaust valves. Turn screw clockwise for closer clearance. (Fig. 6-3) (Note) 1. The adjustment must be made with a cold engine and the clearance measured with a thickness gauge. @ Adjusting screw 2. When locking the adjusting screw locking nut hold the screw to prevent its turning. 3. Inspection a. Check t o make sure that the tappet clearance is within standard tolerance. Too small a clearance will cause the valve to stay open with a consequent pressure leakage which will result in hard starting or no starting at all. b. Check for improper valve timing. c. Check for stretch in the cam chain. IGNITION TIMING ADJUSTMENT @ Timing index mark @ "F" mark Aligning the "F" mark Fig. 6-4. An improper ignition timing, regardless of the accuracy of the valve timing or the proper compression pressure, will not realize a satisfactory engine performance. Ignition timing out of adiustment will seriously affect engine power output as well as the fuel consumption. 1. Alignment o f the "F" @ Breaker point adjusting screws @ Contact breaker @ Contact base plate screws @ Contact base plate Fig. 6-5. Adjusting the ignition timing mark a. Remove the left crankcase cover and align the "F" marking on the generator rotor to the timing index mark on the stator. Check to make sure that the spark is produced across the spark plug gap at this point. (Fig. 6-4) Perform this test by removing and placing the spark plug on top of the cylinder head with the high tension case connected. 2. Adjustment Make the adiustment if required, by loosening the contact breaker adiusting screws. When the ignition timing is retarded, move contact breaker foward the right. 0 0 When the ignition timing is advanced, move the contact breaker toward the left. 3. Breaker paint gap, 0.3 t o 0.4 mm (0.01 2-0.016 in.) max. @ S e r v ~ c e tester Fig. 6-6. @ Battery Tmng l~ght @ Cord Improper ignition timing will result in combustion to take place at the incorrect point of compression, making it impossible t o obtain smooth engine operation the throttle grip will require greater opening, consequeuntly, the fuel consumption is increased. 6.7 MAINTENANCE INSPECnON Results of retarded ignition timing: 1. Drop in power output. 2. Drastic increase in fuel consumption. 3. Engine overheats with a possibility o f piston seizure. Results of advanced ignition timing : 1. Produces knocking and drop in power output. In severe cases, damage to piston, connecting rod, crankshaft may result, therefore, periodic ins~ectionshould be oerformed. 2. Upon completion of the point gap and ignition timing adjustment, check for proper dperation of the spark advancer by the use of a timing light. Checking the operation of the spark advancer with a tachometer. Refer to section service tester on page 123. 4. CONTACT POINTS Inspect the surfaces of the contact points; if they are burnt or pitted, dress the surface with an oilstone or a point dressing file so that the points are making parallel contact. (Fig. 6-7) C1) Normal @ Worn contact point After the points have been dressed, wash in @ Side contact point @ Dirty contact ~ o i n t Fig. 6-7. Fkeaker point contacting condition gasoline or trichloroethylene to remove all trace of oil. Insufficient breaker point gap. a. The spark tends to linger, that is the interruption of the primary circuit i s not completed at the points, therefore, the secondary high voltage build up is reduced. b. The closed duration of the points is longer, producing heat and resulting in damage. c. In conjunction with @ above, the points will be late in opening with a consequent delay in the ignition timing; this will cause a drop in power output. Excessive breaker point gap a. The duration that the points are closed i s too short to allow for sufficient current flow in the primary circuit with a consequent low voltage build-up in the secondary high voltage circuit. This condition will cause poor engine starting, ignition missing at high speed and resulting in loss of power. b. Engine over-heats readily. c. The ignition timing is advanced. 5. SPARK P L U G ADJUSTMENT A dirty or damaged spark plug or plug electrode which are eroded will not product a good strong spark, therefore, the spark plug should be inspected periodically and cleaning and adiustment made. Spark plug with sooty wet electrodes, or electrodes covered with deposits will permit the high tension voltage to bypass the gap without sparking. 1. Cleaning a. The use of the spark plug cleaner is the recommended method of cleaning the plugs, however, a satisfactory cleaning can be performed by using a needle or a stiff wire to remove the deposits and then wash in gasoline followed by drying with a rag or compressed air. (Fig. 6-81 @ Spark plug @ Spark plug cleaner Fig. 6-8. Cleaning the spark picg 6. PERIODIC ADIUSTMENT 141 b. Adjust the spark gap after cleaning. Set the gap t o 0.6-0.7 mm (0.024-0.028 in.) by bending the electrode on the ground side. (Fig. 6-9) Spark Plug Inspection a. Check tbe spark intensity produced between the gap of the ground and the center electrodes by observing the color. Blue spark Red spark ..,.,....... ............ Good condition Poor condition Cause due to : 1. Low supply voltage @ Thickness gauge @ Spark plug Adjusting the spark plug gap Fig. 6-9. 2. Defective ignition coil 3. Defective spark plug 4. Absence of sparking may also be due to compression (Note) 1. Do not remove the deposits by burning. 2. When installing the spark plugs, clean the seating area free of oil or foreign matter and install finger tight before torquing with a plug wrench. 3. The spark plugs can be tested after adjustment with the plug tester. With the high tension voltage maintained constant, vary the test chamber pressure and inspect the condition of the spark. 6. FUEL SUPPLY SYSTEM Restriction in the fuel supply system will prevent sufficient fuel flow to the carburetor and cause engine to sputter during acceleration or the engine may stall at high speed. a. Check for sufficient supply of fuel i n the tank. b. Disconnect the fuel feed tube from the carburetor and check the fuel flow with the fuel cock in ' the ON or the RES position. (Fig. 6-10) c. If the fuel flow is insufficient, remove the fuel tank from the body and clean internally. When the flow is still inadequate, remove the fuel cock, disassemble and clean. Fuel cock S : STOP R : RESERVE Fig. 6-10. (Note) 1. The insufficient fuel flow may be caused by the plugged vent hole in the filler cap as well as the restriction in the fuel line. (Fig. 6-1 1 ) 2. The fuel cock is switched to RES (reserve) f ~ o m the ON position when the fuel tank becomes empty. The reserve fuel supply contains approximately. CB/CLl75: 1.8 8 (3.8 U. S. pts., 3.2 Imp. pts.) CB/CL125: 1.5 f? (3.2 U. S. pts., 2.6 Imp. pts.) d. Fuel strainer cleaning The accumulation of dirt and water in the fuel cock strainer cup will cause a restriction in fuel flow, resulting in drop in engine speed and malfunction of the carburetor. Clean the cock, strai~er and the filter screen at periodic interval. Fig. 6-1 1. Sectional view of the fuel tank cap 6.7 7 42 MAINTENANCE iNSPECTlON 7. FUEL STRAINER CLEANING The foreign substances contained in the fuel passes through the fuel line from the fuel tank and enters the strainer cup. The foreign substances and water. if not arrest in the strainer cup will enter the cylinder and causes engine malfunction. 1. Cleaning a. Set the fuel cock lever to the STOP position. b. Remove the strainer cup. c. Clean inside the strainer cup and filter screen. (Fig. 6-1 2) 8. OIL FILTER SCREEN CLEANING @ O ring @ Screen @ Fuel stroiner Cleaning the fuel strainer cup Fig. 6-12. The engine oil is filtered through a system o f double filters, the centrifugal rotor oil filter and the pump filter screen before being supplied to the various parts of the engine. When the impurities have accumulated in the filters to prevent its proper function, the oil supply to the various parts are starved and eventually result in seizure and damage to the engine. It is therefore, important that the filters be cleaned periodically. 1. Cleaning Remove the right crankcase oil filter cover to get access t o the rotor oil filter and for access t o the pump filter screen, remove the right crankcase cover. Clean the units in gasoline. 9. AIR CLEANAR SERVICING An air cleaner clogged with dust restricts the free passage of inlet air .and result in power loss or drop in acceleration, therefore, to assure proper performance, periodic cleaning of the air cleaner should be made. I . Removal Remove the seat to get access to the air cleaner. Reler to section 49 B on page 1 18. 2. Cleaning Tap the air cleaner lightly to loosen the dust and then blow dry compressed air from the inside or use a brush. (Fig.6-13) (Caution) 1. The air cleaner is made of paper and if torn or damaged, will cause dust t o enter the engine cylinder, resulting in increased cylinder wear, therefore, replace with a new element. 2. Oil or water on the cleaner element will render it ineffective by restricting the flow of air and causing a drop in power. @ Air cleaner element @Air gun Fig. 6-13. Cleaning the air cleaner elemenl 143 6. PERIODIC ADJUSTMENT 0. CARBURETOR CLEANING AND ADJUSTMENT A dirty carburetor or carburetor out of adiustment will cause poor engine performance. As an example, a carburetor set to a lean fuel air mixture will cause the engine to overheat while a rich mixture will cause engine to run sluggish. Further, overflowing of fuel from the carburetor is a possible fire hazard, therefore, periodic cleaning and adiustment should be performed. 1. Cleaning a. Disassemble the carburetor and wash the parts in gasoline. b. Blow out the nozzles with compressed air and after cleaning and reassembly, make the adiustment. 2. Idle adjustment The idle adiustment is performed with both the throttle stop screw and the air screw by the following procedure. (Fig. 6-14) 0 Throttle stop screw @ Air Screw Fig. 6-14. Adlusting the carburetor e. At this throttle stop screw setting, recheck the carburetor adjustment by manipulating the air screw. f. After the idling adiustment has been completed, check the carburetor by snapping throttle and also check the throttle response. (Note) 1. All adjustment should be made after the engine has attained operating temperature. 2. Adjust both carburetors alternately through each of operations. 6. LUBRICATING The purpose of lubrication is to prevent direct . . surface to surface contact of the moving parts by providing a film of oil between the svrfaces and thereby, reducing friction and preventing wear. It also serves to cool the parts from the heat produced by friction. Further, the lubricant penetrates between the piston and cylinder to form an oil film which act as a seal to maintain the cylinder pressure. 1. PARTS NOT REQUIRING PERIODIC OIL CHANGE OR LUBRICATION @ Drain plug Fig. 6-15. Removing the drain plug There are some parts which only require Iubrication whenever the parts <.re disassembled for repair or replacement. Steering stem steel balls and cone race Throttle grip Main stand Grease 6.7 7 44 MAINTENANCE INSPECTION b. The proper oil level is indicated by the oil level markers on the gauge when checked without screwing the cap down. (Fig. 6-16) 1. Oil plays a prominent role in the life and the trouble free oerformance of an enaine, therefore, it is very important that. the oil change be performed periodically and refrain from using dirty oil over a long period. The more frequent the oil change, the betrer it i s for the engine. 2. When refilling or adding oil, it should not be filled above the specified level. Overfilling will cause oil pumping with consequent fouling of the spark plug. 3. Use only recommended oil of proper grade. ., @ Oil level gauge @ Upper levelmark @ level Fig. 6-16. Oil level gauge Fig. 6-17. Oil C. DRIVE CHAIN ADJUSTMENT An excessively sla'ck drive chain will cause chain to whip, whereas an over-tension condition will produce resistance, resulting in lowering the power output at the rear wheel. Always maintain the chain at the specified tension. C. Periodically clean and lubricate the chain. Lack of oil will cause the chain links to bind and cause undesirable effect on the sprocket. a Drive chainInspecting drive chain tension Fig. 6-18. @) Alignment mark @ Adjusting bolt @ Adiuster Fig. 6-19. Adlusting the drive chain @ Lock nut 7 45 6. PERlODlCA DJUSTMENT BRAKE ADJUSTMENT Brakes are the life-line of the rider, therefore. do not neglect to perform the periodic inspection. daily inspection and pre-riding inspection. FRONT BRAKE ADJUSTMENT @ Free ploy of the lever Fig. 6-20. 1. Lever free play a. The free play of the brake lever, that is, the distance between the normal attitude and the point where the brake starts to take hold should be 2-3 cm (0.73-1.1 2 in). ~diustmentcan be made at the cable adjuster at the brake lever, by ioosening circular lock nut and screwing the adiuster in t o increase the lever play and screwing the adjuster out to. decrease the free play. b. Adjustment is also made by the adiusting nut. (Fig. 6-21) Turn to the right to decrease the free play. Turn to the left to increase the free play. 2. REAR BRAKE ADJUSTMENT 1. Pedal free play @) Lock nut @ Adlusting nut Fig. 6-21. Adjusting the front brake lever a. The free play of fhe broke pedal, that is the distance between the normal attitude and the point where the brake starts to take hold should be 2-3 cm (0.78-1.1 2 in) (Fig. 6-22) b. Adjustment is made by the adjusting nut. (Fig. 6-23) Turn to the right to decrease pedal play. Turn to the left to increase pedal play. c. When the braking stroke is small, the following condition is apparent. 1. Too small a clearance between brake panel and shoe. 2. Loss of tension in the brake spring. 3. Brake lining damaged due to overheating. SPOKE TORQUING @) Free play of the pedal Fig. 6-22. Riding with loose spoke will place an ununiform loading on the rim as well as on the remaining spokes, therefore, the spokes should be inspected frequently and retorqued when they become loose. Raise the wheel off the ground and check each spoke for tightness, any spoke which are noticeably loose should be torqued to the same value as the remaining spokes so that the spokes are all of uniform torque. Use the spoke nipple tool and torquing wrench. F. BATTERY INSPECTION @ Adjusting nut Fig. 6-23. Adjusting the rear broke pedol Loss of battery electrolyte occurs after long use and should be replenished periodically. When the electrolyte level drops to the point where the plates are exposed, it will result in rapid discharge to the battery. The battery should always be maintained at the proper electrolyte level. 6.7 MAINTENANCE INSPECTION I. Electrolyte Level a. Remove the air cleaner cover disconnect the battery cable from the battery, remove the battery setting bolt and then remove the battery. The standard battery used i s the MBW3-12C (CB/CL125 : 836-6) [Mfg. by Yuasa Battery Co.) b. Always maintain the electrolyte level above the lower electrolyte level marking on the battery. When replenishing, add distilled water to raise the electrolyte level to the upper marking. (Fig. 6-24) c. Replenish by unscrewing the battery cap at the top and add the distilled water. All three battery cells should be filled to the same level. @ Lower level mark Bottery electrolyte level @) Upper level mark Fig. 6-24. 2. Damaged and Dirty Battery Cable Connect~r Inspect the connectors for cleanliness and damage. Clean the dirty connectors or replace damaged connectors before making connection and apply a coating of grease or vaseline on the connectors to prevent corrosion. 3. Specific Gravity Check the specific gravity of all three cells of the battery with a hydrometer. if it measures below 1.200, the battery should be charged. A fully charged battery should indicate a specific gravity of 1.280 at electrolyte temperature of 20°C (68'F). The specific gravity will vary somewhat with the temperature at the rate of 0.00017 specific gravity variation for each 1OC (1.8OF1 charge in temperature. A rise in temperature will cause a decrease in specific gravity and vica versa. (Fig. 6-25) (Caution) 1. Do not add any sulfuric acid to the distilled water when replenishing. 2. When the drop in electrolyte level is excessive, check the discharge rate of the battery. 3. Exercise care not to pinch the battery cable when making the battery installation. 4. Also, make sure that the vent tube is not pinched. 5. When the temperature drops, the capacity of the battery will lower and cause hard starting. In such a case, store the motorcycle in a warm place. @) Hydrometer @ Bottery Measuring specific gravity Fig. 6-25. 7 46 7 47 6. PERIODIC ADJUSTMENT G. SECURITY INSPECTION OF PARTS Fig. 6-26 @ @ @ @ @ @ @ @ Handle installation nut Steering stem nut Front axle nut Rear axle nut Wheel spokes Rear cushion upper and rear nuts Rear fork pivot bolt Engine hanger bolts @ Rear brake torque bolt nut - 150-250 kg-crn 110.1 18.1 ft. Ibsl 900- 1,200 kg-crn 165.1 -86.8 ft. lbsl 700-900 kg-crn (50.6-72.3 ft. Ibsl 900- 1,100 kg-crn (65.1 -79.5 ft. Ibsl 15-20 kg-crn (1.0- 1.5 ft. lbsl 200-350 kg-crn (14.5-25.3 ft. lbsl 500-600 kg-crn (36.1 -43.4 ft. Ibs) 8 rnrn : 200-300 kg-crn (15-21.7 ft. Ibsl 10 rnrn : 300-400 kg-crn (21.7-28.9 i t . Ibsl (Fig. 6-26, 27) 150-250 kg-crn (10.8- 18.1 ft. Ibsl 6.2 PERIODIC lNSPECnON AND SERVICING 6.2 PERIODIC INSPECTION AND SERVICING A. Daily inspection It is of utmost importance to perform periodical inspection and servicing so that troubles can be prevented and the motorcycle maintained in the best of operating condition. The inspection is classified into two types, namely, the pre-riding inspection performed by the rider daily and the periodical inspection which is performed at a regular schedule either by the rider or the service shop. Fig. 6-28 @ @ @ @ The following items of- inspection should be performed daily as a matter of habit. (Fig. 6-28, 29) @ Front tire air pressure 1.8 kg/cm2 (25.6 lbs/in2) Check for excessive looseness or sway of the handle. Check for proper free play of the clutch lever. ,@ Rear tire air pressure 2.0 kg/cm2 (28.5 Ibs/in2) Check the function of the headlight, taillight, stop@ Check the horn for sound and loudness. light and turn signal lights. @ Check for proper play of front brake lever. Check for looseness and oil leaks in the front and 0 correct leveland condition of engine rear cushions. CB/CL175 : 1.5 8 (3.2 U.S. pt., 2.7 Imp. pt.) Check fuel quantity. CB/C1.125 : 1.2 4 (2.5 U.S. pt., 2.1 Imp. pt.) ~ ~ 1 2 5 / ~ :~ 10.5 1 74 5 (2.8 U.S. gal., 2.3 Imp. gal.) @ Check for proper play of the rear brake lever CL125/CL175 : 9.5 4 (2.5 U.S. gal., 2.1 Imp. gal.) ? 49 6. PERIODIC ADJUSTMENT (Note) After inspecting the above items, attention should be paid t o the following points when riding. 1. After starting, warm up the engine for t w o minutes at l o w speed. W h e n the engine is cold, the viscosity of the oil is heavy and does not permit adequate lubrication t o all parts 2. D o not race the engine needlessly. 3. Refrain from sudden acceleration o r braking, tight cornering. 4. Check battery electrolyte level weekly without fail. Under the following conditions, checks should be made a t a more frequent intervals. a. Riding in mountainous area. b. M o r e frequent inspection is necessary when riding a t high speed. Periodic Inspection Periodic inspection and servicing should be performed in accordance with the following table. \Intervals by speedometer It*ms Change engine oil /././././@j.l./././ele/@/e I Adjust ignition timing ........................................................................................................................... ............... a Adjust valve clearance a ............. ............................................................................................................................................................. Adjust cam chain ........................................-.......................................... Adjust clutch ....................................................................... a ............ I* ................................................................................................ Adjust carburetor ................................................................ .................................................................. ................................................................................................................. e . . . . . . . . . . . . ....................................................................................................................................................................... Adjust drive chain Adjust front and rear brake ................................................................................................................................................ Clean spark plug ........................................................... ....... ...........--..... Clean oil filter ........................................................................................... a a ..................... .... ........... . ........ . a . ........... ............... 0 Clean air cleaner ................................................................................................................................................................................................ a a ................ Clean fuel strainer ........................................................................................................ ......................................................................... Clean muffler ............................................................................................................................................. Check tightness of spokes ......................................................................................................................................................................... Retighten nuts and bolts Adjust lighting equipments and hnrn ............................ Check battery . . ...........I. ......... ......... . . . *. ................ 7.7 ENGINE 7. TROUBLE SHOOTING It is most important that the cause of any trouble be located as soon as possible and the proper corrective action taken so that the serviceable life of the engine will b e extended. Listed in the following tables are the troubles, probable causes and the corrective actions. 1. MAIN ENGINE TROUBLE I Troubles 1 I Probable causes 1. 2. 3. 4. running. Corrective action Clean and inspect. Clogged fuel cock. Plugged vent hole in fuel tank cap. lmproper tappet clearance. The carburetor to intake manifold connecting tube damaged or leaking air at the ioints. 5. Improper oil level Engine malfunctions after warm-up. - I I I I Excessive smoke at high engine speed. (oil pumping condition) I I I I I 1. Oil being pumped into the combustion chamber due to excessively worn or By diagnosing the noise, rebore and/or replace the parts as with plugs of correct heat range damaged cylinder, piston, rings and burned during combustion. ( / I I 1 1 1 I Overheating engine 1. Overheated spark plug, replace 1. Worn piston and cylinder Noise produced near the top of the engine - 1. Defective spark plug 2. Defective ignition coil 3. Incorrect float level ( The clearance between the piston and cylinder is increased causing the piston skirt to slap against cylinder wall during combustion. connecting 2. Worn rod large end produces knocking 3. Tappet noise 1. 2. 3. 4. Carbon deposit accumulation Dirty or fouled spark plugs lmproper type spark plugs or gap Insufficient lubrication t o drive chain or chain tension too tight. 5. Oil level too low, poor or improper grade oil 6 . Improper distributor point gap clearance, I / / / / 1 required. 1. Inspect and rebore cylinder and replace worn parts. 2. Replace connecting rod, large end bearing and crank pin. 3. Adjust t o proper specification. 1 1 / 1 Disassemble and clean 2. Clean, dry fouled plugs. Inspect carburetor if plugs continues t o foul. 4. Adjust periodically, lubricate 7. Adjust periodically dirty, burnt 7. Excessive carbon accumulation in combustion chamber Engine does not start llock of compression) 1. Foreign object caught between valve and valve seat 2. Tappet stuck open 3. Ignition timing out of adjustment 1. 2. 3. 4. Disassemble and clean Adjust Adjust Replace new fuse 7. TROUBLE SHOOTING 757 1. Clogged fuel cock 2. Fuel passage in the carburetor clogged 3. Dirty spark plugs (heavy carbon deposit or wet plug) 4. ignition timing out of adjustment 5. Blown fuse 1. Disconnect the fuel line and check the fuel flow 5. If the fuse is blown, the pilots lamps will not light up Oil becomes emulsified (especially during winter) 1. Water mixed with oil 2. Use of improper type oil 3. Clogged breather pipe 2. Use Honda Ultra Oil or equivalent oils (Caution) The oil, even though clean in appearance, may decomposed due to extended use and become thin, resulting in loss of lubricating properties. Should be replaced. Increased fuel consumption. (Related symptoms) Low exhaust noise, low back pressure at muffler Low compression noticeable when kick starting. 1. Clogged air cleaner 2. Distributor point gap out of adjustment, dirty, burnt 3. Excess accumulation of carbon in cylinder exhaust port or inside muffler. 4. lgnition timing retorted 5. Worn cylinder, piston, piston ring. 1. Service air cleaner element 2. Adjust gap clearance, rework or replace burnt points 4. If ignition timing is retarded, the distributor points will open after the timing mark " F " has been passed. Adjust to proper setting Insufficient engine rpm. 1 . Fuel passage clogged 2. Defective spark plug (fouled) 3. Clogged muffler 4. Clogged air cleaner 5. lgnition timing out of adjustment Poor throttle response (check first t o see that the throttle cable is properly adjusted) 1. 2. 3. 4. Clogged air cleaner. Clogged exhaust port or exhaust pipe lgnition timing out of adjustment Tappet clearance out of adiustment 1. 2. 3. 4. Points covered with oil Improper ignition timing Defective condenser Condenser in poor condition Engine suddenly while running stalls . I Distributor points burnt / i 1. When the fuel passage in clogges, the spark plugs will be dry. 4. If the air cleaner i s clogged, engine will not develop high RPM and the exhaust smoke becomes dark. Clean the air filter element periodically. Condenser Test Method After taking the resistance value with the manager, use a copper wire t o short across the terminals, a good strong spark should be produced at the instance the leads are contacted. Condenser Measurement With the distributor points open, measure the resistance between the primory terminal and the outer shell, a good condenser should measure at least 5 M Q, resistance at standard temperature. The condenser is defective if it measures below @ Service tester @ Spark @ Condenser Fig. 7-1. Measuring condenser capacity 1 Mi2 Determine the condition of the condenser by the above method. (Caution) A loosely installed condenser or dirty terminal will cause ignition to malfunction. I I 7.2 CARBURETOR 2. 1 52 CARBURETOR TROUBLE Trouble 1. Fuel overflow Corrective action Probable cause 1. Contaminated fuel 1. Remove float chamfer cover a. [related symptoms) Poor idling Poor performance in Remove locking clip and disassemble the float chamber b. Check for any dirt lodge in the valve seat, remove dirt by blowing with compressed air or by unscrewing the valve seat, and clean. all speed Excessive fuel consumption * Hard starting c. Low power outpu'. Poor acceleration Reassemble after gasoline. cleaning in 2. Damaged valve or valve seat 2. Replace both the valve and valve seat with new parts. 3. Punctured float 3. Remove the float chamber cover, take out the float and check for fuel in the float. (Checking procedure) Shake the float Immerse the float in hot water 90-95 C 1194-263°F) for approximately 60 seconds, bubbles can be observed if the float is punctured. 4. Float arm lip bent Trouble 2. Poor idling (related symptoms) Poor performance at Probable cause 1. Turn the air screw lightly to full close and check to see if the air screw was properly adjusted. Back off 1 %.I;+-% turn from full close. Start the engine and turn the air screw in both direction not more than i turn and set at the point where the engine rpm is highest (smooth). 2. Throttle stop screw out of adjustment 2. Back off the throttle stop screw Poor response to throttle snupping Poor performance at medium speed Corrective action 1. Air screw improperly adjusted slow speed Poor speed transistion - 4. Straighten the arm lip if bent and use the fuel level gauge to obtain the proper fuel level. all the way and check for proper operation of the throttle, turn the stop screw in until the proper rpm is obtained. 3. Clogged slow jet (including pilot jet) 3. Unscrew the plug, remove the pilot jet, check for any dirt, blow out with compressed air if dirty. Remove the slow iet and clean in the same manner. - 7 53 7. TROUBLE SHOOTING @ Throttle stop screw @ Air screw Fig. 7-2. Adiusting idling (CB/CL 175) Corrective action Probable cause Trouble 3. Poor performance at 1. Clogged slow jet (includk, pilot jet) 1. Same corrective action as for poor idling intermediate speed (related symptoms) 2. Jet needle at improper setting 2. Adjust t o the I3 stages) 3. Improper fuel level 3. Replace worn jet needle with Flat spot Poor acceleration Excessive fuel con- new part. sumption Trouble symptoms) Loss of power - Poor acceleration Use the fuel level bending the float arm lip. 4. Clogged air vent formance (related stage gauge and adjust the level by Poor speed transition 4. Popr high speed per- proper 1. 2. 3. 4. 5. 4. Clean out the air vent Probable cause Corrective action Loose main jet or clogged with dirt 1. Remove main jet and clean, install and tighten securely. Clogged air vent tube Choke closed Fuel cock improperly positioned 2. Clean out vent tube 3. Open the choke t o full OPEN Loose jet heedle 4. Black exhaust smoke position Position the fuel cock lever t o full OPEN position. Poor engine 5. If jet needle locking clip is performance broken, replace with a new part. 5. Hard starting 1. Excessive use of choke 2. Fuel overflow 3. Fuel cock in closed position 1. Start engine with choke valve fully open (clean spark plug) 2. Same corrective action as 1 above 3. Open fuel cock 7, E N G I N E 3. ENGINE NOTICE Corrective action Probable cause Trouble 1. Tappet noise 1. Excessive tgppet clearance 2. Worn tappet 1. Adjust t o proper clearance 2. Repair or replace 2. Piston slap 1. Worq piston, cylinder 2. Carbon deposit in combustion chamber 3. Worn piston pin bore, connecting rod 1. Repair or replace 2. Remove carbon 3. Repair or replace small end 3. Cam chain noise 1. Tensioner out of adjustment 2. Stretched chain 3. Worn teeth on cam sprocket, timing sprocket 1. Readiust 2. Replace 3. Replace 4. Clutch knock 1. Worn clutch friction disc outer tab area 2. Worn clutch center spline 1. Repair or replace 2. Repair or replace 5. Crankshaft noise 1. Crankshaft end play 2. Worn crankshaft bearing 1. Repair or replace 2. Repair or replace 6. Engine noise 1. Chafing between kick arm and oil seal 2. Breaker point noise, defective slipper surface 1. Repair 2. Replace A.C. generator lmogneto noise) 4. I assembly STEERING SYSTEM i Trouble 1. 1 an die operates heavy 2. Front or rear wheel Probable cause I Corrective action 1. Overtorqued steering cone race 2. Damaged steering steel balls 3. Bent steering stem 1. Readjust 2. Replace 3. Repair 1. Loose bearing in front or rear wheel 1. Check for wear and replace as 2. Bent rim on front or rear wheel 3. 4. 5. 6. 7. required 2. Straighten by loosening or tight- Loose spoke ening the spokes. Worn rear fork pivot bushing Twisted frame 3. Replace if uncorrectable Drive chain adiuster out of adiustment 4. Replace 5. Repair or replace 6. Adjust t o proper value 7. Replace Defective tire 1. Right and left cushion not balanced, 3. Pulls to one side 1. 2. 3. 4. 5. 6. front or rear. 2. Misalignment of front and rear cushions 3. Bent front fork 4. Bent rear fork 5. Bent front axle I 1 6. Loose component in steering system 1 Replace Replace Repair Repair Repair Repair 7. TROUBLE SHOOTING 7 55 5. CLUTCH SYSTEM Corrective action Piobable cause Trouble 1. Clutch slips 1. Loss of tension in clutch springs 2. Worn or warped clutch plate 3. Worn or warped clutch friction disc 1. Replace 2. Replace 3. Repair or replace 2. Clutch will not 1. Excessively worn clutch friction disc 2. Improper adjustment 1. Repair or replace 2. Adjust to proper specification 1. Warped clutch plate or friction disc 2. Uneven tension of clutch spring 1. Repair 2. Measure tension and repair or disengage 3. Clutch out of adjustment replace (engine stalls) 6. GEAR C H A N G E SYSTEM 1. Gears will not engage Corrective action Probable cause Trouble 1. Broken lug on shift drum 2. Broken lug on shift arm broken 3. Unsmooth movement between shift drum and shift fork 4. Broken shift fork 5. Broken lug on counter shaft second 1. 2. 3. 4. 5. 6. Replace Replace Repair Replace Replace Replace and third gear 6. Broken lug on main shaft second and third gear 2. Gear change pedal not returning 1. Broken shift return spring 2. Gear shift spindle rubbing against case 1. Replace 2. Repair or cover 3. Gear iump out of engagement 7. 1. Worn lug on counter shaft second and third gear 2. Worn lug on main shaft second and third gear 3. Worn or bent shift fork 4. Broken or loss of tension of shift drum stopper spring 1. Repair or replace 2. Repair or replace 3. Replace 4. Replace SUSPENSIONS 1. Soft suspension 2. Hard suspension Corrective action Probable cause Trouble 1. Loss of spring tension 2. Excessive load 1. Replace 1. Ineffective front cushion damper 2, lneffective rear cushion damper 3. Suspension noise 1. Cushion case rubbing 2. Interference between cushion case and spring 3. Damaged cushion stopper rubber 4, Insufficient spring domper oil (front and rear) 1. 2. 3. 4. Inspect cushion spring and case Repair Replace Replace 7. F R A M E 8. BRAKE SYSTEM Probable cause Trouble Corrective action 1. N o range of adjustment 1. Worn brake shoe 2. Worn brake cam slipper 3. Worn brake cam 1. Replace 2. Replace 3. Replace 2. Unusual noise when applied 1. 2. 3. 4. 1. Replace 2. Remove foreign obiect 3. Repair 4. Replace 3. Ineffective braking 9. 1. 2. 3. 4. 5. Worn brake shoe Foreign object lodged in brake lining Pitted brake drum surface Worn brake panel bushing Inoperative front brake cable Loose brake rod Improper shoe contact Dirt or water inside the brake Oil or grease on brake lining 1. Remove foreign object from cable and inspect for bends 2. lnspect and repair 3. lnspect and repair 4. lnspect and repair 5. lnspect and repair DRIVE CHAIN Trouble 1. Drive chain stretch rapid 2. Excessively worn sprocket Probable cause Corrective action 1 . Excessive load applied to chain (during riding or gear change) 2. Due to oil leak, excessive lubrication periodically 1. Correct riding technique 2. Perform proper lubrication 1. Driving with worn sprocket 2. Sprocket malfitted to drive chain 1. Clean sprocket area 2. Replace with proper sprocket CB125 WIRING DIAGRAM Cl.125 WIRING DIAGRAM HEAD 6V 25 CB175 WIRING DIAGRAM CL175 WIRING DIAGRAM (General Export type) LlGHlNG BEAM SWITCHING ARRANGEMENT R.REAR TURN SIGNAL CO 3 40 E! b 6 b 3 BI G Gr ......BLUE ...... GREEN ......GRAY ...... ..... A.C GENERATOR ...... Br BROWN Y.... YELLOW p...... PINK o...... ORANGE L B I ......LIGHT BLUE R......RE0 LG-. -LIGHT GREEN LG/R ......LIGHT GREEN AND RED W/Y- ....WHITE AND YELLOW YELLOW AND RED Y/R Br/W .BROWN AND WHITE R/W ......RED AND WHITE G/Y ......GREEN AND YELLOW W ......WHITE BK ......BLACK CL175 WIRING DIAGRAM (U. S. A. Export type) 9.1 DISMOUNTING AND MOUNTING ENGINE 1. DISMOUNTING ENGINE [CB/CLI 7 5 ) 1. Remove the step bar, kick starter pedal and gear change pedal. 2 . Remove the muffler. 3. Remove the spark plug caps from the spark plugs. 4. Remove the cylinder head R. side cover and remove the tachometer cable by unscrewing the setting screw. 5 . Remove the seat. 6. Shut off the fuel cock and remove the t w o fuel tubes from the carburetors. 7. Uncouple the electric leads connecting. (Fig. 9-1) 8. Loosen'the air cleaner tube bands and remove the remove the throttle valve from the carburetor. 9. Remove the L. crankcase rear cover and remove drive chain at the ioint clip. 10. Remove the clutch cable from the clutch lever. (Fig. 9-2) 11. Remove the stater magnetic switch. Fig. 9-1. Disconnecting electrical leads (CB175) @ Clutch cable @ Clutch lever Fig. 9-2. Removing clutch cable 12. Pull out the engine hanger bolts (9 each) and remove the engine t o the right side. (Fig. 9-3) @ 10 mm bolt @ 8 mm bolt Fig. 9-3. Removing engine hanger bolts 763 8.1 DISMOUNTING AND MOUNTING ENGINE [CB/CL125] 1. Remove the step bar, kick starter p e d a l a n d g e a r change pedal. 2. Remove the muffler. 3. Remove the spark plug caps from the spark plugs. 4. Remove t h e tachometer c a b l e from the right side o f the cylinder head. 5. Remove the seat. 6. Shut o f f the fuel c o c k a n d remove the fuel tubes from t h e carburetors. Fig. 9-4. Disconnecting electrical leads Iconnectors) @) Throttle valve Fia. 9-5. Removina throttle valve @) Clutch cable @ Clutch lever Removing clutch cable Fig. 9-6. @) 10 mm bolt @ 8 mm bolt Removing engine hanger bolts Fig. 9-7. 7. Uncouple the electrical leads a t the connectors. (Fig. 9-4) 9.2 ENGINE MECHANISM (CBICL7 75) (Note) Attach the wire t o both ends o f the chain before disconnecting. 4. Remove the cylinder head. @ Cam chain ioint Fia. " 9-8. 1 Removina cam chain 4 5 . Remove the cylinder setting bolt and remove the cylinder. B. Inspection Refer t o page 21. @ Cam chain tensioner Fig. 9-9. Pushing down tensioner align the "T" mark o n the rotor yo the index mark o n the stator. The will position the piston t o the top-dead-center. Position the "0" mark @ Fig. 9-10. pin @ O ring @ Gasket o n the cam sprocket t o the t o p positio?, connect the chain with the joint clip. The position o f the clip must be in the position shown in Fig. 9-8. (Note) When both sides o f the cylinder head cover a r e removed, install the cylinder head side covers before connecting the cam chain. Loosen the valve tappet adjuster before installing the side cover. @ "0" mark Fig. 9-1 1. Installing cam chain 164 7 65 9.2 ENGINE MECHANISM (CB/CL 7 75) ..- .. . --. .... 4 . Install the cylinder head cover and tighten the mounting nuts. (Eight cap nuts and one hex. bolt1 (Note) Perform the torquing in a diagonal pattern, starting from the inside and working outward. Torque to 160-210 kg-cm (1 1.6- 15.2 ft-lbs) 5 . Loosen the cam chain tensioner lock bolt and then retighten; followed by setting the lock nut. (To tighten the cam chain) O 6 mm bolt Fig. 9-12. Nut tightening sequence 6. Adiust the valve tappet clearance. 0.05 mm (0.002 in.) cold setting. Adjust to Camshaft When removing the camshaft from the cylinder head, first remove the pin at the right side o f the camshaft and then remove from the cylinder. @ Camshaft @ Knock pin Fig. 9-13. Removing knock pin 9.2 ENGINE MECHANISM (CBICl.775) 7 66 I t @) Valve cotter @ Valve retainer @ Outer valve spring @ lnner valve spring @ lnner seal @ Valve stem seal cap @ Valve spring seat B @ Exhaust valve guide @ 0 ring @ Stem seal rubber cushion @ Valve stem seal @ Exhaust valve @ Valve spring seat @ Inlet valve guide @ Valve guide clip @ lnlet valve @ Valve tappet adjuster @ Rocker arm @ Rocker arm shaft @ Knock pin @ Camshaft @ Cam chain @ Dowel pi^ @ Valve tappet adjusting lock not Fig. 9-14. @) Dowel pin Fig. 9-15. 9.2 ENGINE MECHANISM (CBICf.775) 767 P A 2. CRANKCASE A. Disassembly 1. Remove the cylinder head and cylinder in accordance with 9.1 on page 164. 2. Remove the L. crankcase cover, A.C. geherator, and starting sprocket in accordance with section 3.3 on page 32-33. 3. Remove the R. crankcase cover, clutch, o i l pump in accordance with section 3.4 on page 34-36. 4. Remove the gear shift spindle and kick storter spring. 5. Loosen the crankcase setting nut and bolts and separate the lower crankcase. (Note) Crankcase tightening bolt is installed under the o i l drain plug, therefore, do not forget to remove the bolt. (Fig. 9-16) 8 mm cop nu1 @ 8 mm bolt Q 6 mm bolt Fig. 9-16. Removing lower crankcase B. Inspection Refer to section 3.6 C on page 41. C. Reassembly Assemble the crankcase in the reverse order of disassembly with attention paid to the following point, Clean the crankcase and inspect the mating surfaces of the crankcase for sign of leaks, scrotches and other damages. Apply liquid gasket to the mating surfaces of the crankcase, assemble after drying. Make sure that the two dowel pins are installed on the upper crankcase. @ Dowel pin Fig. 9-17. 3. GEAR SHIFT MECHANISM To prevent the gear shift arm from disengaging with geor shift drum, a projection is provided on the upper crankcase to limit jumping of geor shift arm. Further to facilitate shifting into the neutral gear, the neutral stopper is made to fit the drum directly. (Fig. 9-18) @ Gear shift arm Fig. 9-18. Q Projection 9.2 ENGlNE MECHANISM (CB/CL 7 75) 6. Separate the transmission gears from the upper crankcase. @ Gear shift drum stopper 7 68 Q Neutral stopper Fig. 9-19. 7. Remove the gear shift drum stopper, neutral switch from the gear shift drum. (Fig. 9-19) Remove the shift fork clip, shift fork knock pins and pull out the shift drum. (Fig. 9-20) @ Gear shift drum Removing gear shift drum @ Gear shift fork Fig. 9-20. B. Inspection 1. Measure the thickness o f the gear shift fork tip. Use a vernier caliper. (Fig. 9-21) Standard Value R. L and center shift fork 0.21 1-0.2142 (5.36-5.441 Limit Replace if under 0.203 (5.16) @ Gear shift fork @ Micrometer Fig. 9-21. Measuring gear shift fork tip 2. Measure inside of the gear shift fork. Use a cylinder gauge or inside micrometer. (Fig. 9-23) Standard Value Shift fork 1.339- 1.340 (34.0-34.025) Limit Replace if over 1.342 134.075) @ Gear shift fork Fig. 9-22. @ Cylinder gauge Measuring inside diameter 7 69 9.2 ENGINE MEC 3. Measure outside diameter of the gear shift drum. Use a micrometer t o make the measurement. (Fig. 9-23) C. Reassembly Reassembly is performed in the reverse order of the disassembly procedure, however, special attention should be given t o the following items. @ Gear shift drum Q Micrometer Measuring outside diameter Fig. 9-23. 1. When assemblying the gear shift fork into the upper crankcase the shift fork should be assembled from the left side in the order of the stamped markings "R", "C" and "L" so that the letters are facing t o the left. (Fig. 9-24) 2. Make sure that the shift fork guide pin is installed and then properly set the clip. 3. Check the shift fork t o assure that it is operating smoothly. @.Gear shift fork Q Clip Fig. 9-24. 4. After assemblying the gear shift spindle move it as shown in Fig. 9-25 and check t o make sure that i t positively returns t o normal position. @ Gear shift arm Fig. 9-25. 5. Make sure that the gear shift spindle is positively set with the washer and circlip. (Fig. 9-26) @ Circlip Fig. 9-26. Q Washer 9.2 ENGINE MECHANISM (CB/CL7 75) 7 70 CRANKSHAFT When assemblying the crankshaft into the crankcase, give proper attention t o the following points. 1. Install the dowel pins into the upper crankcase and positively align the dowel pin holes in the crankseaft bearings t o the dowel pins. Work w i l l b e simpliged by aligning the .scribe line o n the bearing outer t o the parting surface o f the crankcase. (Fig. 9-27 and 9-28) 2. Refer t o page 41-43, section 3. 7. @ Dowel pin @ Upper crankcase Fig. 9-27. and lightly rock the gear being measured. Measure the amount o f bockiash using a Small dial gauge. (Fig. 9-29) / 1st. 2nd, 3rd gears 4th and 5th gears Standard Value 0.0017-0.0052 (0.044-0.1331 0.0016-0.005 10.042-0.126) I @ Crankshaft @ Scribe line @ Upper crankcase Fig. 9-28. Ser:!?pble - ...... Replace if over 0.008 (0.2) Replace if over 0.008 10.21 2. Gears when used for a long period w i l l develop wear t o the teeth and dogs as well as resulting in side loading o f the gear teeth. This becomes the cause o f gear noise and in severe case, gear disengagement. Gear which are excessive w o r n should b e replaced in sets. -- 3. Measurina aear-shaft clearance @ Small dial gauge Measure the bore o f the gear with a cylinder gauge o r an internal micrometer, measure the shaft diameter with a micrometer and compute the clearance. (Fig. 9-30) Fig. 9-29. Checking gear backlash Limit 0.0008-0.0024 M5, C 1 10.016-0.045) C2, C 3 @ Gear Fig. 9-30. @ Cylinder gauge @ Shaft @ Micrometer Measuring diameter 7 77 9.2 ENGINE MECHANISM (CBICL775) 20 mm set ring Q Transmission counter shaft @ 6304 HS radial ball bearing @ Ball bearing set ringA Drive I sprocket fixing plate @ 6 X 10 hex bolt @ Guide pin 2 0 X 5 2 X 9 oil seal @ Drive sprocket @ 16 mm bearing bush B @ 16 rnm thrust washer @ Counter shaft low gear (36 T) @ Counter shaft top gear 125T) 20 mm thrust washer B @ Counter shaft fourth gear (27 T) @ 20 mm thrust washer @ 20 mm thrust washer B @ Transmission main shaft Counter I shaft second gear l 3 2 T ) @ Counter shaft third gear L29T) @ @ Mainshaft top gear 125 T) @ Mainshaft shifting gear (23 T & 20 TI @ Mainshaft second gear @ Bearing bush A @ @ @ @ @I 8 X 2 5 X 8 oil seal Fig. 9-31. 9.2 ENGINE MECHANISM (CB/CL 175) C. Reassembly Perform the reassembly in the reverse order of disassembly, however, special attention should be given be to the following items. 1. Do not use the circlips which have been removed, use only new parts. 2. Install all gears, washers, and circlips properly as shown in the Fig. 9-31. 6. KICK STARTER 1. When installing the kick starter assembly into the upper crankcase, align the kick starter spindle pin groove to the dowel pin in the crankcase, and positively set the friction spring to the case groove @ Kick starter spindle Fig. 9-32. @ Friction spring @ Dowel pin @. 7. CARBURETOR A piston valve type variable venturi carburetors are mounted one to each cylinder. A. Disassembly 1. Remove the carburetor mounting bolt, loosen the air cleaner connecting tube clamp. 2. Position the fuel cock to OFF, and remove the fuel tube. @ Throttle stop screw Fig. 9-33. 3. The carburetor can be removed after removal of the throttle valve. B. Inspection 1. Idle adjustment The carburetors must be adjusted after the engine has warmed up to operating temperature. Further, both the right and left carburetors must be adjusted at the same time. (Fig. 9-33) a. Adjust the engine idle speed to 1,200 rpm with the throttle stop screw. b. Manipulate the air screw back and forth and set it to the point of highest rpm (the air turn per from screw should be set to 1 full closed position). xf @ Fuel level gauge Fig. 9-34. @ Float @ Carburetor c. Readiust the idling speed to the proper setting with the throttle stop screw. 2. Float level adjustment Remove the float chamber cover and check the position of the float with the fuel gauge, as shown in Fig. 9-34, at the point where the float arm just comes in contact with float valve. (Carburetor is tilted approximately 10°1. Adjustment is made by bending the float arm with a small screwdriver. The fuel level gauge is Tool N o . 07401 -001 0000. 9.2 ENGINE MECHANISM (CBICL 7 25) 7 73 @ Contact breaker assembly @ Spark advancer @ Contact breaker setting screw Fig. 9-35. 3. Unscrew the spark advancer mounting bolt and remove the spark advancer from the camshaft. (Fig. 9-35) 4. Unscrew the three cross screws and disassemble the point base. 5. Unscrew the two cam sprocket mounting bolts and remove the sprocket from the end o f the camshaft. 6 . Disconnect the chain being careful not t o drop the ioint clip into the cylinder, and then, with a piece o f wire the both ends of the chain. 7. Loosen the six cylinder head attaching nuts t o @ Hex nut @ - Cap . nut Fig. 9-36. remove the head. Nut tightening sequence 8. Inspection Refer t o section 3. 2. 1 C on page 66-67. C. Reassembly 1. Tighten the cylinder head cover nuts uniformly in the sequence shown Fig. 9-36. 2. The mounting o f the cam chain can be simplified i f the chain is reassembled prior to the installation o f the cam sprocket left and right bolts are o f d.ifferent sizes, therefore, exercise care that they are not installed in reverse order. (Fig. 9-37) "0" mark Fig. 9-37. @ Knock bolt @ 6 m m hex bolt 9.2 ENGINE MECHANISM (CB/CL125) @ Joint clip 1 74 @ Cam chain Fig. 9-38. @ O i l seal @ Pin @ Spork advancer groove Fig. 9-39. B, Inspection @ Rocker arm shaft stopper @ Rocker arm shaft Measure the base circle and cam heights with a micrometer. (Fig. 9-41) I I Ser~~pble *a,,,., 0.826-0.828 (20.98-21.02) Cam base Cam height (including base circle) Standard Value IN C. Reassembly Refer to cylinder head reassembly procedure. @ Cam shaft @ Micrometer Fig. 9-41. Measuring cam height 1 75 9.2 ENGINE MECHANISM ('CBICL125) 3. CAM CHAIN TENSION The design has been simplified, making it perform with high degree of reliability and also providing easy adjustment. @ Cam chain tensioner push rod @ Tension spring @ Tensioner spring A @ Lock nut @ Cam tensioner adjust Fig. 9-42. A. Disassembly 1. Remove the generator rotor by using the rotor (Fig. 9-43) puller (Tool No. 07933-200000). @ Generator rotor Fig. 9-43. @ Rotor puller 9.2 ENGINE MECHANISM (CBICL725) 7 76 2. Remove the L. crankcase cover by removing the cam chain adiust bolt and eight 6 mm screws. (Fig. 9-44) @ Cam chain adjust @ 6 mm screw Fin 9-Ad. 3. Remove the starting sprocket set plate and then remove the starting chain together with sprockets. (Fig. 9-45) 4. Remove the cam chain tensioner set plates and remove the cam chain tensioner. (Fig. 9-47) @ Starting sprocket set plate @ Starting motor sprocket @ Starting sprocket Fig. 9-45. B. Inspection Cam chain adjustment can be made in accordance with following procedure. a. Remove the dynamo cover. b. Rotate the dynamo rotor counterclockwise until the "T" mark on the rotor lines up with the timing index mark on the stator. This adjustment must be made when the pistons are on the top of the compression stroke. This condition can be determined by shifting the tappets with fingers. If the tappets are free, it is an indication that the pistons are on the top of the compression stroke. @ Cam chain tensioner Fig. 9-46. c. Unscrews the cam chain tensioner adjust bolt and rotate the dynamo rotor counterclockwise one turn. d. Screw the cam chain tensioner adjust bolt and then tighten the lock nut. C. Reassembly Check t o make sure that tensioner operates smoothly in the direction indicated by the arrow in Fig. 9-47. Fig. 9-47. Q Tensioner set plate 7 77 9.2 ENGINE MECHANISM (CBICL725) 4. TRANSMISSION The CB type is equipped with a 5-speed transmission while model CL125 is equipped with a 4-speed transmission. Fig. 9-48. Neutral Fig. 9-48A. 1st gear (C1 shifted) 3rd gear (C1 shifted) Fig. 9-48 8. 2nd gear (Csshifted) Fig. 9-48 (3. Fig. 9-48 D. 4th gear (MaMzshifted) Fig. 9-48 E. 5th gear IMsMz shifted) 9.2 ENGINE MECHANISM (CB/CL 125) 7 78 A. Disassembly 1. Disassemble the cylinder head in accordance with section 4. 1 . A or page 173. 2. Remove the cylinder. 3. Remove the L. crankcase cover generator rotor, starting sprocket and cam chain tensioner. 4. Remove the R. crankcase, oil filter, clutch, oil pump and gear shift spindle. 5 . Remove the 8 mm and 6 mm bolts from the upper crankcase. (Fig. 9-49) 8 mm bolt . 9-49. @ 6 mm bolt i 6. Remove the 8 mm and 6 mm bolts from the lower crankcase and separate the upper crankcase. (Fig. 9-50) 7. Separate the transmission gears. -- @ 6 mm bolt @ 8 mm bolt Fig. 9-50. B. Inspection 1 . Measuring backlash Hold the mating gear so that it does not move and lightly rock the gear being measured. Measure the amount of backlash using a small dial gauge. (Fig. 9-51) 1 1st. 2nd. 3rd gears 1 Standard Value 0.001 7-0.0052 10.044-0.133) 1 SerE:ble 1 Replace if over 0.008 12.01 2. Gears when used for a long period will develop wear to the teeth and dogs as well as resulting in side loading of the gear teeth. This becomes the cause of disengagement. Gear which are excessive worn should be replaced in sets. @ Small dial gauge Fig. 9-51. Measuring gear backlash 77 9 9.2 ENGINE MECHANISM (CS/CL 725) 3. M e a s u r ~ n ggear s h ~ f tclearance Measure the b o r e o f the gear w ~ t h a cylinder gouge o r a n Internal micrometer, measure the shoft d~arneter w ~ t h a m ~ c r o m e t e r and compute (Fig. 9-52) the clearance Standard Value - -- - 00008-0 0024 10 02-0 0 6 2 1 00006-00018 M5 C1 0451 -- - -- - 10 016-0 -0.0016-0 003 C2 C3 (004-00821 M4 - @) Gear @ Cylinder gauge @ Shaft Fig. 9-52. Measuring diameter (Q @ @ @ @ @ -- -- - -- I Serviceable L m ~ t -- -- 1 1 / Replace ~f over 0004(01l Replace if over 00047 (0121 @ Micrometer Knock pin, 6 x 9 B @ 15 mm bearing bush B @ Counter shaft low gear @ Counter shoft fourth gear @ Counter shaft third gear @ Counter shaft top gear @ 20 mm thrust washer A 20 mm set ring @ Ball bearing set ring B @ 6204 HS ball bearing @ 20 mm 0 ring Counter shaft top gear @ 2 8 X 4 8 X 7 oil seal @ Drive sprocket @ Drive sprocket fixing plate Transmission counter shoft Main I shaft fourth gear @ Main shaft second & third gear 6 X 10 hex bolt @ Transmission main shoft @ Main shaft top gear @ 15mm bearing bush A @ 8 X 2 5 X 8 oil seal Fig. 9-53. 9.2 ENGINE MECHANiSM (CBIC1725) C. Reassembly Perform the reassembly in the reverse order of disassembly, however, special attention should be given to the following items. 1 . Do not use the circlips which have been removed, use only new parts. 2. Install gears, washers, and circlips properly as shown in the following figures. (Fig. 9-53) 3. Position all the gears in neutral and rotdte by hand to assure that the dogs are not hitting and that the gears are all rotating smoothly. 4. After assembl~ing the gear assemblies into the upper crankcase, make sure that the set rings and dowel pins are properly installed. 5. GEAR SHIFTING MECHANISM To prevent the gear shift arm from disengaging with gear shift drum, a projection i s provided on the upper crankcase to limit jumping of gearshift arm. Further to facilitate shifting into the neutral gear, the neutral stopper is made to fit the drum directly. (Fig. 9-54]. A. Disassembly 1. Remove the cylinder head and cylinder. 2. Remove the L. crankcase cover, generator rotor, @ Gear shift arm @ Projection @ Neutral stopper bolt Fia. 9-54. starting sprocket and cam chain tensioner. 3. Remove the R. crankcase cover, clutch, ail pump and gear shift spindle. 4. Separate the lower crankcase from the uppercase. 5. Separate the transmission gear from the upper crankcase. 6. Remove the shift drum stopper, neutral stopper bolt and neutral switch. 7. Remove the shift fork setting clips and guide pins. 8. Remove the gear shift drum from the crankcase. B. Inspection @ Gear shift fork @ Micrometer 1. Measure the thickness of the gear shift fork tip. Use a vernier caliper. Right, left B cehter shift fork (Fig. 9-55) / Standard Value 1 0.211-0.215 15.35-5.45) / / / 1 Fig. 9-55. Measuring gear shift fork tip Serrz:b'e -...,.. Replace if under 0.1985 (5.05) 2. Measure inside diameter of the gear shift fork. Use a cylinder gauge or inside micrometer. (Fig. 9-56) @ Gear shift fork @ Cylinder gauge Fig. 9-56. Measuring inside diameter 787 9.2 ENGINE MECHANISM (CBICl.725) / I Shift fork C. Standard Value 1.339- 1.340 (34.0-34.025) / SeryEpb'e - ...... Replace if over 1.342 (34.0751 Reassembly Reassembly is performed in the reverse order of the disassembly procedure, however, special attention should be given to the following items. 1 . When assemblying the gear shift fork of the CB @ Guide pin clip Fig. 9-57. type (5-speed transmission) into the upper crankcase the shift fork should be assembled from the left side in the order of the stamped markings "S", "C" and "L" so that the letters are facing to the left. (Fig. 9-57) 2. Make sure that the shift fork guide pin is installed and then properly set the clip. 3. Check the shift fork t o assure that it is operating smoothly. 4. After assembly the gear shift spindle move it as shown in Fig. 9-58 and check t o make sure that it positively returns t o normal position. @ Gear shift arm Fia. 9-58. 5. Make sure that the gear shift spindle is positively set with the wosher and circlip. (Fig. 9-59) @ Washer Fig. 9-59. @ Circlip 9.2 ENGINE MECHANISM (CB/CL 7 25) 6. KICK STARTER When the counter shaft As to start. the pinion t o @ Low gear Fig. 9-60. kick starter is operated, the kick starter pinion moves toward the right and engages with the low gear t o transmit the force t o the piston through the main shaft. This causes the engine the starter pedal is released, the force of the kick stater spring rotates the spindle and returns the nor:r,al position. (Fig. 9-60) @ Kick starter spindle @ Circiip @ Friction spring @ Kick starter pinion A. Disassembly Refer t o page 79. B. lspection Check to make sure that the action o f the kick starter spindle i s smooth. C. Reassembly Reassembly is performed in the reverse order of disassembly procedure, however, special attention should be given t o the following items. 1 . When installing the kick starter assembly into the upper crankcase, align the kick starter spindle pin groove to the dowel pin in the crankcase, and positively set the friction spring t o the case groove. 2. Assemble the kick starter spindle and check t o assure that it is operating properly. @ Dowel pin Fig- 9-61. @ Groove @ Kick starter spring 7 83 9.2 ENGINE MECHANISM (CBICL7 25) a Disassembly Refer to page 56-61. Inspection 1. Idle adjustment The carburetors must be adjusted after the engine has warmed up t o operating temperature. Further, both the right and left carburetors must be adiusted at the same time. (Fig. 9-62) @ Throttle stop screw @ Air screw Fia. 9-62. a, Adjust the engine idle speed t o 1200 rpm with the throttle stop screw. b. Manipulate the air screw back and forth and set it t o the point o f highest rpm (the air screw should turn open from full closed be set to position). lx+g c. Readjust the idling speed t o the proper setting with the throttle stop screw. 2. Float level adjustment @ Fuel level gauge Fig. 9-63. @ Float @ Carburetor Remove the float chamber cover and check the position o f the float with the fuel level gauge, as shown in Fig. 9-43, at the point where the float arm just comes in contact with the float valve. (Carburetor is tilted approximately lo0). Adjustment is made by bending the float arm with a small screwdriver. The fuel level gauge is Tool No. 07401-001 0000. 9.3 F R A M E 9.3 FRAME 1. FRONT SUSPENSION Refer t o page 90-95 of this Manual for the information o n the front suspension o f a l l other models. CL175 : The front cushion compression stroke 4.53 in (1 15 m m ) while the extension stroke is 1.38 in (35 mm) f o r a total travel o f 5.91 in (150mm). @ Front fork bolt Q 24 mm washer @ 0 ring @ Front fork top bridge @ Front fork bottom bridge @ Front fork pipe @ Front fork dust seal @ Front cushion spring 41 mm internal circlip @ Front fork oil seal @ Front fork pipe guide @ Front piston stopper ring @ Fork valve stopper ring @ Front damper valve @ Fork piston stopper ring @ Front fork piston @ Fork piston snap ring @ Front fork bottom case Fig. 9-64. internal circlip using the circlip pliers. 7. (Fig. 9-66) Draw the front fork pipe assembly out bottom case. of the @ Front for top bolt @ Headlight bracket setting bolt Fig. 9-65. @ 8 mm bolters B. Inspection 1 . Check front fork damper o t l (disassembly is not necessary). If the o i l is dirty o r the level low, change o r replenish the oil. @ Circlip @ Pliers Fig. 9-66.. 9.3 F R A M E Remove the front fork top bolt and drain plug on the damper and allow o i l t o drain followed by stroking the damper several times to get complete removal. (Fig. 9-67) Replace the drain plug and fill with 155-165cc (9.5-10.1 cu-in)of good grade SAE #low-30 or equivalent. 2. Front fork piston Measure the diameter of the piston with a micrometer to check the amount of wear. (Fig. 9-68) / Standard Value I 1.3946- 1.3955 Replace if under ( 135.425-35.451 1 1.3937 135.41 Ser:.?~bke I @ Front fork drain plug @ 'Front fork top bolt diameier Fig. 9-67. C. Reassembly Perform the reassembly in the reverse order of the disassembly, however, particular attention should be given to the following points. 1. First insert the axle through the fork axle holes to make sure that the left and right' forks are level before tightening the 8 mm front fork mounting bolt. (Fig. 9-69) I I @ Front fork piston @ Micrometer Fig. 9-68. Measuring diameter of fork piston 2. When installing the front fork oil seal, apply a liberal amount of the grease between the main seal lip and the dust seal lip (petroleum resisting grease) and exercise care not to damage the lips. Use the dust seal driving weight to drive to the seal. (Fig. 9-70) 3. It is recommended that the fork piston stopper ring and the circlip be replaced with a new item. The old part may have lost its tension or may have become distorted during the removal. 2. REAR SUSPENSION I @ Frot fork 1 @ Front axle Fig. 9-69. The rear suspension utilizes a De Carbon type shock absorber. Compressed nitrogen gas and o i l is sealed within the cylinder and during contraction and extension the oil flows back and forth through the orifice incorporated in the piston ; the function of the valve which controls the flow perform the dampening. Model @ Front fork oil seal driving weigh1 @ Front fork oil seal driving guide Fig. 9-70. Damping force 1 Contraction Extension 1 7 86 9.3 F R A M E @ Rear cushion spring @ Rear damper assembly @ Rear cusion upper case @ Rear cushon spring guide @ Rear cushion bottom case @ Spring adjuster @ Under seat complete Fig. 9-71. CB/CL125 @ Spring seal stopper I iw I I MAX.309, MIN 242 STROKE ?- .76 I NITROGEN GAS \ IST SET 173.5 SET 1685.y3RD SET 163.5 N 2D --I / @ Rubber joint @ Spring seat stopper @ Rear cushion spring guide Fig. 9-72. CB175 1 @ Rear cushion upper case @ Rear damper assembly @ Rear cushion spring MAX. 334. MIN249 STROKE n: 0 0 0 0 @ Spring seat stopper @ Spring upper seat @ Rear cushion spring guide Fig. 9-73. CL175 85 0 @ Rear cushion spring @ Rear damper assembly 7 87 9.3 F R A M E A. Disassembly 1 . Separate the rear cushion assembly from the frame. 2. Remove the rear cushion spring by using the rear cushion removal tool. (Fig. 9-74) (Note) The r e a r damper contains nitrogen gas under pressure, therefore, i t should n o t b e disassembly due t o the extreme hazard. B. Inspection 1. Rear cushion spring (Fig. 9-75) @ Rear cushion Q Rear cushion disassembling & assembling tool Fig. 9-74. Measure the free length o f the rear cushion spring using a vernier caliper; replace i t is beyond the serviceable limit shown below. The spring compressive force is also shown as reference. Spring free length Standard 1 Serviceable Value Limit Replace if 7.257 CB125 ( 1 84.3) CL125 701 Model I I -75 CL175 @ RearI cushion sprina - @ - Vernier calioe~ 7.807 ( 1 88.3) 8.331 (211.6) I 6,1;!:; Replace if 6.~t4; 74) Replace if 7$.8;:5) Compressive force 6.8307 XI32 1bs (173.5 mm/14.5 kg) 6.8307 in/44.1 Ibs 1173.5 mm/20 kg) 7.874 in/32 lbsl 200mm/14.5 kg) Fig. 9-75. C. Reassembly Reassembly is performed in the reverse order o f disassembly. Install the spring so that the end with the smaller c o i l pitch is toward the top. 3. FRONT WHEEL The front brake utilizes the t w o leading type brake shoes t o provide superior braking performance. Refer t o section 4. 12, page 1 1 1 o f this Manual for the descriptton o f the component parts. @ Front brake lever @ Free play Fig. 9-76. A. Disassembly Refer t o section 4. 12 8, page o f this Manual for the disassembly procedure. B. Inspection 1. Front brake pedal adjustment (disassembly is not necessay). a. Place a black under the engine t o raise the front wheel o f f the ground. b. Spin the wheel b y hand slowly apply the brake lever until the brake starts t o take hold, measure the amount o f lever travel a t the tip. The standard lever travel 3/8-3/4 i n (1 - 2 cm). (Fig. 9-76) 9.3 F R A M E ".-" . , "-, 3. Front brake shoe wear disassembly. Perform the brake adjustment in accordance with section 6 inspection above. @ Lock nut @ Cable adiuster Fig. 9-77. Q Vernier l calipe Fig. 9-78. 4. REAR WHEEL Rear wheel components. @ Circlip @ 8 mm Special tongued washer Fig. 9-79. 7 88 9.3 F R A M E until the brake start to take hold ; measure the amount o f the brake oedal travel. The 1 @ Rear brake pedal -. -- @ Free play normal pedal travel when measured at the forward tip should be 3/4- 1.1/4 in (2-3cm). (Fig. 9-80) Fig. Y-80. c. Perform the adjustment with fhe rear brake adjuster nut. (Fig. 9-81) 2. Rear brake drum wear Check the wear of the brake drum by measuring the inside diameter o f the drum with a vernier caliper. If the wear is beyond the serviceable limit shown below, the brake drum should be replaced. CB125 @ Rear brake adiuster nut Fig. 9-81. CL175 Standard Value Serviceable Limit 5.1 10-5.126 . .- . .- . - - .-, 5.512-5.514 1140- 140.3) Leolace i f over I - -- ,. - -. Replace i f over 5.60 1142) 3. Rear brake shoe wear Measure the thickness o f the brake shoe with a vernier caliper and i f i t is worn the beyond the serviceable limit shown below, the shoe should be replaced. Standard Value 0.1 67-0.169 14.0-4.3) 1 I Serviceable Limit Replace if under 0.08 12.0) 4. For the inspection o f the other items, refer t o section 4. 13 C, page 1 16. 9.4 ELECTRICAL ELECTRICAL 9.4 1. CHARGING CURRENT MEASUREMENT Connect an.ammeter between the battery I + ) terminal and the selenium rectifier, and check t o see i f the values obtained are in accordance with the standard specifications listed in the chart below. When the battery charge is low, the cause may be in the A. C. generator, selenium rectifier o r the defective wiring. I Item Model CB 175 Day time Max. 2,400 rpm Night time Max. 2,800 rpm Battery voltage - Charging start Charging current /3,000 rpm Charging current 15,000 rpm - Min. 0.5 A Max. 3.0 A Min. 0.5 A Max. 3.0 A 13 V 16.5 V 12.3 V Charging current /I0,000 rpm - CL 175 Day time Max. 2,400 rpm Night time Max. 2,800 rpm Battery voltage CB 125 13.2 V Min. 0.5 A Max. 3.0 A Min. 0.5 A Max. 3.0 A 14V 16.5 V Day time Max. 1,300 rpm Min. 2.0A Min. 2.7 A Max. 4.5 A Night time Max. 1,900 rpm Min. 1.2A Min. 2.0 A Max. 4.0 A 6.3 V - 7V 8.3 V - Battery voltage CL 125 - 6.7 V 1 p p Day time Max. 1,300 rpm Night time Max. 2,000 rpm Battery voltage 6.3 V - Min. 1.7 A Max. 3.0 A Min. 1.7 A Max. 3.5 A 7V 8.3 V 2. STARTING MOTOR (CB175/125) Starting motor is mounted at the front of the crankcase. The power t o drive the crankshaft is reduced in speed by a planetary gear incorporated within the starting motor and further reduced at the sprocket and chain connecting the motor t o the crankshaft. Starting motor specification and characteristics (Fig. 9-82). 2. If the solenoid switch has been used for a long period, the contacts will become pitted or burned, creating a high resistance which will prevent flow of current t o properly operate the starting motor. such condition develops, dress the contact points with a file o r sandpaper. When RPM kgm KW x103 3.0- 1.8- 0.6- 12- 2.5- 1.5- 0.5- 10- 2.0- 1.2- 0.4- 8- 1.5- 0.9- 0.3- 6- 1.0- 0.6- 0.2- 4- 0.5- 0.3- 0.1- 2- (CB175) RPM kgm x I@ KW 3.0- 2.4- 0.3- 2.5- 2.0- 2.0- V 1.6- 0.2- 1.5- 1.2- 1.0- 0.8- 0.1- 0.5- 0.4- (CB125) Specification Items 12 V 0.35 k W 30 sec. 6.44 Rated voltage Rated output Intermittent operation Reduction ratio Without load With load Lock Voltage 11.5V Current Max. 28 A 9.4 V l00A Max. 240 A Min. 0.55 kg-m Min. 1.5 kg-m - Torque RPM. Output Min. 2000 rpm Min. 500 rpm - Min. 0.33 k W Items - Specification Rated voltage 6V 0.25 k W 30 sec. 6.44 Rated output Intermittent operation Reduction ratio Without load With load v Voltage 5.5 Current Max. 40 A 2.8 V Min. 0.55 kg-m Min. 1900-2700 Output Lock Max. 300 A Torque RPM 6.7 V rpm Min. 1.5 kg-m Min. 400 rpm Min. 0.22 k W A. Disassembly 1. Remove the L. crankcase cover. 2. Remove the generator rator by using the rotor puller. 3. Remove the starting sprochet set plate. 4. Remove the starting chain together with sprockets. 5. Remove the starting motor cable from the starting motor. 6. Remove the two starting motor setting screws and then remove the starting motor. 7. Remove the starting motor side cover and remove the carbon brush (Fig. 9-83). @ Carbon brush setting screw Fig. 9-83. @ Carbon brush 7 93 9.4 ELECTRICAL lnspection 1. Measure the amount o f brush wear with a vernier caliper. (Fig. 9-84) Standard Value 0.433- 0.492 I11 - 12.5) I I Serviceable Limit Replace if under 0.197 (5.0) Also check to make sure that the brush is not binding in the holder causing the brush the to float away from the commutator. 2. Measure the starting current @ Carbon brush Fig. 9-84. Use a service tester and an external shunt to measure the starting current. (Refer t o page 1361 C. Reassembly Reassembly is performed in the reverse order of the disassembly procedure. 3. STARTER SOLENOID SWITCH A large current is required to operate the starter and if the starter circuit was connected directly to the push button switch on the handle, the switch will burn out. A starter solenoid of a large capacity is installed between the battery and the starting motor. Wnen the push button switch is pressed, the solenoid coil is energized, creating an electromagnet which draws is the iron core. A heavy duty electrical contacts are mounted to this iron core which closes the circuits between the battery and the starting motor. A. Disassembly 1. Disconnect the starting motor cable from the solenoid switch. @ Stopper @ Stopper holder @ Insulation washer @ lnsulation collar A @ Contact spring @ Flat washer @ Plunger holder @ Plunger shaft @ Plunger @ Contact bolt @ Case @ Contact plate @ Yoke @ Coil bobbin @ Coil complete @ Return spring @ Body Fig. 9-85. 2. Unscrew the two mounting bolts and remove the starter solenoid switch. 8. Inspection 1. Press the starter switch listen for the click in the solenoid switch, i t is an indication that the plunger within the solenoid switch is functioning. C. Reassembly Reassembly is performed in the reverse order of the disassembly procedure. CB175 WIRING DIAGRAM (General Export Type) CB175 WIRING DIAGRAM (U.S.A. Type) Cl.175 WIRING DIAGRAM (U.S.A. Type) . I 9 4' L.FRONT TURN SIGNAL LIGHT p......pink Gr.--.Grey LB-.-Light Blue LG-..-Light Y/R--...Yellow/Red LG/R.---Light GreenIRed Br/W.*--.Brown/White W/Y.-....White/Yellow G/Y-.-Green/Yellow R/W.--.Red/W hite W/Y.tube......White/Yellow tube R. tube....-Red tube . Green CB125 WIRING DIAGRAM LIGHTING DIMMER STATER SWITCH (RH) COMBINATION SWITCH R. FRONT TURN SICNA R 3 HEADLIGHT 6V30/25W X 2 b 9 SIGNAL LIGHT 6VlOW Lighting Dimmer Switch HORN SWITCH (LH) .........~ t g h tGreen Swilching Aran~ment IGNITION SWITCH SWITCHING ARRANGEMENT B~......... B~~~ p .........P ~ n k 6 .........Green .....Re,, Gr .........Gray W .........White Yellow LB""". ..Light B l w Y BrownIWhile Br/W. ~ / y Green/Yellow , ........... ............ LC/R...'........ R/W W/Y y / ~ ......... Light Green/Red ............Red/Whtle ............ Wbite/Yellow ............Yzllow/Red 9.5 WIRING DIAGRAM