HONDA- 250, 30- l-IONDA MOTOR 00.. LTD HONDA 250 WDEL C872 PREFACE This Shop Monuol contoins general dato and inlormotion. ond procedures relative to motorcycle maintenance. ovenhavl and repairs for the models covered by Hondo 250 and Hondo 300 equivalent to Model 0724377. CB72-CB771 CS72'CS77. Therelore, inlormation in this manual will be suitable instruction lor servicemen ond mechanics ol Hondo to assist them to efliciently service and repair these machines. Now. in this oose, mechonicol arrangement means to repair 0 motorcycle when it is out ol order and restore it to the ordinary stote a well as to prevent it lrom any trouble by periodically inspecting the motorcycle. The contains of this book ore divided into live chapters, including main stondords, disossemny—ossembly, construction, wiring diagram and trouble shooting. Each chapters ore separated into sections. Disassembly-assemblylthe 2nd chopterl is divided into 2 sections— Engine and Frame. The section of Engine is described both model C72' 77, CB72'77, but that of Frame is done only model CB72-77. In regard to the Frome ol model C72-77, please refer to the previously published Shop Monuol lor Hondo 125- 150. An effort has been mode to produce a manual avoiding fundamental principle ond theory by explaining the actual mechanism. Special emphasis has been placed on illustrations ond charts to make it eosy for the service man to understand Without reading every line. We hope this Will be of Some use to you. This manual will be revised without notice. January. 1960. HONDA MOTOR CO., LTD. TECHNlCAL SECTION EXPORT DEPARTMENT No. 5—5, Vaesurcho, Chuorku. Tokyo. Japan MAINTENANCE STANDARDS C572 .77 . DISASSEMBLY & ASSEMBLY . CONSTRUCTION . ELECTRIC EQUIPMENT . TROUBLE SHOOTING MAINTENANCE STANDARDS,C 72-77 For maintenance operation tor HONDA 250»300, Maintenance Standards, specification and dimension ore listed hereofter for reference. EXPLANATION : Maintenance Items Items to be inspected, service-wise. Standard Value This indicates the manufacturer's standard size or the standard size after newly assembling or adjusting, and shows the size-limit of completed part in the permissible limit of adjustment. Repairing leltI Unusable wear limit 01 parts requiring correction or replacement, function-wise. Remarks Unmarked numbers are run unit and men unit shown underneath, and others according to the umt indicated. UNIT IN CHART : Unmarked numbers are m/m unit and inch unit shown underneath, and others according to the unit indicated. 1. GENERAL PERFORMANCE . . CONTENTS 2. ENGINE 3. A. _:|:G).'"r"p_0Pa FRAME mp0? .163?" Cylinder. Cylinder Head Crank Shaft (Pisron, Connecting Rod] .. . Cam. Timing and Valve ....... Upper Crank Case Clutch, L. Cronk Cose Cover Transmission ............................................ Magneto. Contact Point Oli Pump. Oil Filter Kick, it. Crank Case Cover Under Crank Cose and charm Handle ....... Front Cushion Front Fork Steering. Tank ........... Frame Body Saddle. Stand Rear Fork. Chain Case . . .. Rear Cushion .................... Front Wheel ............................ Rear Wheel qua-mun MAINTENANCE STANDARDS (Model C72) Tms muinrenunce Slandards 1s 11sled only aboul the dam: o1 Mode1 C72. 1h 11m 115! dimenrians withum unils 1ndicale and ovhers accordmg to the unils 1ndicaled 1 . GENERAL PERFORANCE "1111' (Upper soap: and “war" (down step). l I e m Standard 1spomrg me Remrks Compression pressure 0519,1013 7.0 Check with kick 120.071b/m? 99.541b/in’ m1 consumplmn 42745101/9 29 SEMI/11121 7m11s’m 26.044700 17.98 mile/ é Lubricunr censumerion 120 “/1000 km 200/1000 a less mom 120 :c/ézu mlle 200/620 mlle Max, speed 13mm”, 90 ICES The pesmre 15193117 50-60 "Illa/h 55 8G "“9 1 123119331: 022: 2. ENGINE A. Cyllnder, Cylinder Heed n e .1 Standard iepmrinq Limi Remarks Cyhnder (finer din. 53.994100 54.1 more 21255-41259 2.129 Max, out or round w11hm 0.001 0.05 mm 0.00019 Taper w11hm 0.001 0.05 mm: 0.00019 Over 5122 of cylmder Over Size 025 3 calegory 01 0.25 0.00904 10.00981 over s1ze Cy11nder head valve Widm 1.0~1.5 2.0 Male sheer 0039340590 00757 Ang1: 459 Compression H1110 as The cupudly of the 0.326 combustion cham CY'W‘e‘ ”93“ gaskeI Flames wumn 003 0.06 more be" ”3'94“ smace 00011 00023 Cylinder heed gaskel Thmkness 1.0—1.1 1n mse 01 bmding 0039-0043 Cylinder my nu1 Tighvness 2.1 m.kg 15.18911“: B. Crank Shall (Piston, Connecting Rod) nem 51mm ‘gpulv‘lng mm! mm; Plslon lap diumeVer 53.55~53.60 535 less we pvoglessive ‘ 2.108~2.HO 2106 dlrection ol the. Max dia. ‘ 54-1-0 :0 539 less 'Dwe'W" “5“" *0 0? 2.122 001 of round D4014~ 0.1 61=d D—lo 005~ 1 0.0051211 Plslon L Eyllndev Min, clearance D 01 more . 0.0039 :0le" pm Dia. 1507150005 15.05more 0.5945907 0.5925 Pismn over size Oval 5119 1 025 3 :ulegory of 00095 1 0.25 1000931 Taper 070 083—0 00 “3' 5‘13 07000311170003 1011.21.11 1an Thickness “~23 2.31M; 009470.102 0.0905 wmm 1780~L795 I] lass 00700700709 0.0669 Tens-m l.75~l.05l:g (lopl 0.519 less rungemlal tension 1 1.704.00kg (2nd 1 l l.653~2.315lb 13230 les 1 111 case of bindlng 1.543~2.2051b ‘ End gap 015~o.3s 00 more ‘ 00059700137 0.0314 Top, 21111 ring & nng Clearance 00170.04 l 0.1 more gmave 0.0003~0.oo15 0.0039 Oil ling Thlckness l 2,4~2.s I 2.0 less 1 00944701023 ‘ 0.0787 Widvh 2.780~2.795 2.1 less 1 01094701100 ‘ 0.10629 Tenslon 0.770919 05 less Tanwfiul .enslm 1,5435~1.9845| . l l025|b End gap 0170.3 0.9 move u. (use 01 bindmg 0.0039700118 1 00314 all ring a. ling gvoDvE Clealance 0.017004 0.1 more 0.0003~0.001s o 0039 :0le" oval size Over 5129 . 0.25 3 category or 0,0098 0 25 10.00901 Piston pm 001. die. 149947150 14.95 leg: 1 ”"e' 5‘” 0.5903 ' 0,5905 0.5095 mm 1mm 45.57457 ‘ 17913—17992 . I to in Standard :pu'iving [tinii Remarks Piston pin a piston C|eurunce 070.012 0.05 more in mid, posn in 0—00004 0.00190 somy by iirrgers Connecting rod or. die. 15010—15040 15.08mare smoli end 0.5911~o.5922 0 5930 Cori. rod smoH end& Clearance 0 010—0049 0.08 more piston pin 00000—0 0019 0 0031 Con, rod smoti end Swmg 3.0 more Max. ampiitude to 0.118 oxioi direction oi crank pm Lowerend oHon rod Ami titeeroii,L 007—033 0.5 more O.D027~0 012 0.01% Diogonui cieororice 0000—0 010 0.05 more 0 0002~0i0006 U 001% Big ond~5moH end 01‘ Amount of peroilei within 002 over 0.1 A1 ‘enath 0' con. md 0.000713 0.0039 100mm 13.93iri1 Distortion within 002 over 0.1 N ‘enath 0' 0.00078 0.0039 100 nm 13,93iri Boronser weigtit Om. dio. 24.99~25.00 24,95 orist crankpi'ri 0 9835 ~0 9542 0 9822 R L crank rnott Dla oi rnoit 30.52~30,86 30.0mm 1,210~i,214 1.204 Crank 100" beams Axial cieoronce 0.005 over 0.1 Ceme' heaving 0.00019 0.0039 Rodioi clearance 0 014~0.016 over 0.05 0 0005 '0.0000 0.0019 Crank rnoit Max sWing 0.03 tor; over 0.1 in case at suppomna cumbinauon 0.0011 0.0039 CEF‘E’ h°°""9v ”‘9 swmg oi botn and: Cam chain Ovelall \engm 723.0,..723 8 away 723 28 46 ~28 49 28.00 C. mg and Valve Mechanism Ila rii Slandard Repairing Limit Remark: Ex In mitts guide zri. dia 7.0—7.01 over 7.05 02755—02759 0 2775 Ex. valve Overaii 1engtn 88 65~85 85 85,20rless 3.4?O~3.49B 3.472 cut. die. at s|em e 97~4 9s 0.950r1055 02744~0274e 0.270 Thickness at head 1.0 0.5 orless 003937 001968 in, valve OveraH 1engtn 09,18~a9.3s 88 7 oriess 3511—3511; 3492 cut. dlo. oi slem 6,97~6 98 0.95 uriess o2744~0.2748 0,273 r—_ lrem 51mm :pairing ' Pemmk: Thickness ol head 10 0.5or1ess 0 03936 0.019 Ex. 11. valve Wldth 111%” over 20 003934.059 0.7137 Ex. valve slam and clearance 0.024104 over 008 r gulds 0.0007~0 0015 0.0031 In. valve stem and ‘ Clemente 0.017003 over 0.07 gulde 000394.001] 0.00275 Valve spring ouler Flee lengm 43.82 423mm 1 725 1.665 Tsns'lon 11 6~ 12.4g Ar 345 10111 11 351 p1 242~258kg bmdrrg lewglh 255747.313 A1 275 "11111le 01 53,36~50810 rm 10 Valve spring ouler Decllne mm. 1, 15 more 1 0 03937 0.059 1 Valve spr'lng mner Free 1englr. 34_65 33_4 less 1.364 1.314 Tensifin 3-9fil-30 AI 315mm 1124151 )4.5~15.skg ‘ blndlng lenem 8.59~9,¢slb Al 2¢5 um 10 90101 31377341171I m m, ‘ Decllne mm 1. 1.5 more 0.0393 0059 1 Cam shall Shah are 19 98~l9 99 19.95 less ' 0 756~CL787 0.785 Bend of Shah within 0.01 0.05m“; I 1 0.0003 0.0019 1 Helgm 91 com 1 263872102 26.7 less l.062~1.053 1.051 I 1*) 1+1 ' ' Camshall nnd bearing Clearance 0.0034103 * 008 more | ul journal 00011—00011 0 0031 Valve firnlng Ex. Openlng angle lelare lower :5" P. (6 Cam I [er 1.1mm 10.043101 dead Wm 25-1 i L‘" 'eng‘m Closlng angle ller upper :5° N011 (lcurunte 1 dead 001"! 10" Valve Iimlng 1n, Qpemng angle elore upper :5‘ P. rs cam ‘ [01 1.1 rrm 10.04310f dead pain. we 1 U" 'eng‘h] Closlng angle ller lower :5" Non.dearunce dead ppm 25" Cam sprppkel apupm diame|er 74 706 74 2 less 2.943 2&2 In (use 01 havwg Rocker arm To [ix 'slgps 0.3more some lroublc [>11 on sllpper more 00118 srllppcr sulfate A I ' s m Slandzm Remark; \ In an 13 o~13,027 13.1 move 0.5H~0.512 0.515 Hockey aim (vunkpin \ 00.. dia, 11955—119“ 12.9 ‘25: o.510~o.5i1 0.5073 0.lé~0.61 Clemance m rarkei 29 0.1 mole °'"‘ 0.005—0024 °-°°39 Ex In. yam odiusl Tappel :ieurunce 0.09—0.11 am 0! Com gyms 00035—00043 5""‘da'd Cam chain lensicnev Free iengm 73 70 less spring 2.374 2.755 Tonsinn 16.0~I6.2 lg 10 less 35.28~35.7‘| lb 22.05 Cm. cham Iensioner Om din 59.2—59.3 53.5 less Wuhoui wwy o' roller 2.33—2.35 2.303 iubber i - p -. Slunduvd Reaching um. Remarks Haie shin drum 1.. dia 34.0—34.02 34.2 more 1.33a—i.339 ‘I 346 in cm of axie 120—1201 12.2 more o.472~o.473 0.4303 Cam chain guide roller Om. d a 13.966~13.984 13.9Iess W 0549—0550 0547 Chain guide mile. in die. 14.0—14.01 14.1 more 0.5511—05515 0 5551 lie in Slandmd Emmy ....... ”mu... oimcn Cenlev In, d a 25.0—25.021 24.9 210~21034 20.90.. 0.984~o,905 0.980 ‘ 0326—0130 0.822 Ou|-round swing within 0 I : 0.2 more 0.0039 0 007B Prlma'y drive spmckei Bounm diameter 39.11~39.21 38.3 less 1 5397~1.5436 1.5078 0mm. lriclion disc Thickness AB~49 4.4 iess 0.]889~0.1929 01732 Sham within 0.2 0.5 more 0.0073 0.0195 lien: Standard ‘ repamng 1mm Removks Clmcn plan 51min w11h1n 0.2 0.5 more 00078 0.0196 W1dth OI hock 13.7—138 13.0 less 053937051433 05118 Teem and Dutel of Romy may w11h1n 0.2 06 mare c1u1chpreuur, plate 0.0078 0.0314 01mm spying Free Iengm 33,4 32.4 last 1.3149 1.2755 Tensmn 15.37167 kg 15.0 lass AI 25 mm ID 981 of 19.819 12 0751 1 bmdlng 1engm 33.736~36.823| At 23mm 10.901 01 43.659 lb max, MI F. Trunsmlnlon Ha m ‘ Smnduvd spoiling lel Remavks M1ssmn case lubricot Capacny ' ' ’ mo a1 In crank and rmssmn mg oil 0.396 gal U.5. smndmd Main man 1 om. am. 24959-2493 24.9 less 1 0.98267 0.9334 0 980 Mam man and M2 Clearance 0.074.074 0.1 more gear 0.0039 Axial durecllunolmain Clearance 1 0.1 4.75 1 2 mole man 00039—00295 0.0472 Turning direchon a1 Clearance 0.034.078 01 more M3 gear 0.0011~0.0030 0.0039 Team sunace ofgem Axis may o.oa9~017a 02 more velafing to m1ss10n 00078 Top gear bush 1811) 1n dm. 18.D~18.mfl 18.1 move 3 0.708~0.7D9 0.712 Top gear bush 205:0 In. din. 205—2052 206 more 0807043078 0.31 I Tap gear bush! mam c1earanaa 0.044.092 0.1 more shalt ‘ 0001540032 omgg Dnve sprocket ‘ Bolton 012. 71.541.51 70.5 less 65549—65776 64.7 Ins; 2314:4015 2.77 2.534~2,589 2.54 Ro1ury play 0.034.073 0.5 more Splme pans 0.019 Primary amen 501mm ma, 136.067I36J6 35,3 Ins sprocket 535675.360 5.326 Main shah 3 mp gem Axis play 0.005 01 more beating 0.0039 Counter man a. C2 gear Law gear bush Law gear bush &14mm bush Kick sraner snmdle Kmk smncr spinme a. each bush Kmk spinme p019 Kmk spmdle p019 spring Primary cham Rotary play \n are. Clearance cm. are. Clearance n-pon Frae \ength Looting 0 01 70.098 (1.00039 70.0038 1713-47 15 3.674 _0 675 0.02i0.058 0 00078~0.0022 14341-414 353 0.564~0 565 00670.09 0.00237 0.0035 1 \ u ‘ 0.5511 5w 0 0.1968~0.3937 0.5 more 0.0196 17.2 more 0.677 01 more 0.0039 14.25 105: 0.561 0.15 mare 0.0059 “111?! step 0 C1 mare 0.01 18 2.0 less 0.787 G. Magneto, Contact Poinl f I re m Slandavd Repairing Umn Wemuvis Comacr bysaksr Tensron 0.24.4 In (use or arm spring 01357 135 kg 24 5 "I"! (0 96‘) 0.441 70.882 01 bmdmg \ength in case of 187472.315 25.9 mm 11,0191 Connacr poim Gap 0370.4 on! at 0' max. W 00118700157 smndard r Ignition hmmg Crank ang‘e ahar upper dead DOW 5" Spark advancer. her Rmary number 1100r.p.m. gmning 0! advance angle Spark advancer : and Emory number 3000 r.n.m. cm a! or advance angle srundard H. OH Pump ‘ OII Flliar He m 51mm Pepoumg mm hmuqs 1 011 pump dee 9601 Gearing eccenrnc \ 0003 less 0.1 more 0,003? 011 pump drive gear Bock lush 0.0! 1635 0.5 move Ad1us1 by packmg & ceMer crank gem 0.0039 0.01% on pump packmg Thrckncss 0.4 In case cl bmdmg 010157 Addendum and mnema1 Clearance 00254105 0 1 move wuH ol o1| pump gear 0.00093~o,ool e o 0030 on pump gem Back 105» o 10¢~c 210 o s more 0.00“ ~ 0.0082 0 01% Side and 51de covey o1 Cieuvurwe 0.069~0.04 0 15 more 011 pump geuv 000350~00330 0.0059 Gear pm and gear Geo-unce 005~0 l3 0 I move 0.00 L9 7 0.0051 0.0039 O1| F1119: shah and C1emame 0.012~0.048 0.1 more m1 01121 10101 ).000472~D 0018 0 0039 O1l 171m 101m 001 d1o 57 2 244 0.1 fihel mum Loosmg 5-40 15 morc 0.1?6-«3 937 5 <205 I. chk - I. Crank Case Cover 11.". Standard fly Repavung um Remark: Kick skmerioim51ho|e ‘ Clemente o4 crank case cave! Kick 59u1|el spring Torque o 03~0205 0 0031440050 47 5 mrkg 344 290 11 1b 05 mare 00196 40 less 259 32 In case of use J. Under Crank Case and Change Ira N Standard ‘ "snaking me Remarks ~r 1 Shin drum om. diu 339573397 33.9 less 1.3367 1.337 1.334 om. me. at am “366711.984 ‘ 11.9 1555 no" 0.4722~0.4718 0.4685 511m drum 3. hole of Clearance 002570.075 0.2 more crank cuss 0.00098~0.0029 0.00787 shill drum ‘ Groove mm 0.50 —8,5|5 9.0 more 0.334~0,335 0354 SW for! 1n, die. uf hole 34.0~34.02 34.1 more 1338~I 339 1.34 \ Thmkness 01 end 4.9~5.0 4.5 less ‘ 01929701968 0.177 Senmg Mud be" all Bend (:9 end 0.‘ WNW" 0.8 mare upper, under crank ‘ (10039 ‘ 0.031 me Torque 0.5417 mg ‘ m! m )6xFl,0 \ 3.616~5.063Mb s1undmd Stud Torque I 7~2.0 mrkg )BXPms I 1229~Iué 11le 3. FRAE A. Handle Smndurd Repairing me Remavks Thronle grip Ploy 2—4 mu 0( Check by enema‘ 0.0707 ~04 57 5‘00““ periphevy Thvanle wire differ. Leng|h 61 SHOE bawee" OMS! 2.4015 & inner Blake lever Play 25730 001 01 Check by \ever end 093471.151 "0"de Clutch wive diHO . Length HE Check by lever and . 4.645 Clutch lever 1 Play 15—25 am 01 0.590~0.984 S'flndu'd T_—_4 fi 5 Front Cushion llam Standard lepai'ins lim » Remark: 1 Fvanl cushion unaev 3m, aia. 25.04—26.07 aul ol bush ‘ 1_025~ mes Manda" Pwol bush 8 suspenr ‘ Clearance n.037—o.os sion mm emu—0.00311 Pivol callul Overall length 245—24.; 0.964-D.968 Pwol bush 8 com: Clec'unce 0.016—n.n7 03 mm .00062~0.0027 0.0113 From casmon Stroke 60.3 2.374 From cushlun damp” Damping lame 38—45 kg 20 less By min/sec 9179—9922:: “.10 11168111) o1 plslon OII capacity 39 cc 25 less wmle spindle 011 :60 Front cushiah spring Flee lenglh 27“ 268 less 10.976 10.551 Tension 127.5kg In) less 231.13“: 212.55 Fall 1“ wilhin nui af slandard c- Front Folk - Sleering . Fuel Tank '" m 1 51.111an Repaning L1m1l ‘ Emil! 1 Sleering head stem nul 1 Tarque 65—15ka out 0! ‘ 47,014,..541lllb slandurd Sleenng head Angle 901. Angle helween mdenl and Caster 60" head plpe Tra1l 75 2.952 Fuel ml Cupuuly i 11.5 11 1 ‘ 3.117 gal us. grew uun Um ulu. |/‘ moasa Fleur lork vaDI bolt m, dm. 12_2...12.3 12.6mcre bush mun—0.434 0 496 r \ F. Rear Fork - Chain Case In m Smndurd Repolnng errr Remans Rear broketovqus \mk Hale 12.1~12.2 12.4 mine and 0.476~0.480 0-433 Rear tork pwm bush Out. dlz. 2a.o—2a.oz moz—uos Drrve chain Amount 0! sag 10—20 0111 0| 95 teeth 0393' My, s'undard 1 \ G. Rear Cushion He m swam Repairing leu Remarks Rear cushlun Stmke 61 2.401 Rear cushion damper Dumplng lorce 50—56 kg 30 less A1 0.5 m/sac 113.81 11015—sz 60.15 0! prsmn on capuchy 39 cc :0 less wmte spmdle ml 1150 Rear cusmun spring Free \engm 2|8.4~2|H.9 20" ‘55 8.59B~8.6TS 3.149 mien 150—166kg 143 kg less 330.75—366.03 315.315“; ‘ Tanganfiu‘ (mg‘e 1" mm am at standard ‘ H. From Wheel H: m Slundgrd Repulvmg me Parnell! Fvonl wheel hub ball Axlul play 0005 less 01 more beuung 0.00393 Radlol play 0.01~0.02 0.05 more from bluke pane} om um 21972~21993 2l 9 less space! 00650-405656 o 3.522 Overall lenglh 34 9~351 l 374~ Laal mm axle dlslclnce Ovemll Ienglh c198 —soz collar |,960~l‘976 Brake cum [hickness lll9~12VI 0‘466_ 0476 Flonr broke shoe Om die l74.l_l7M Cunev our diav 6.854~6.866 Flam brake Ilnlng Thlckness 3.5~4.5 2.5 less 0.l37~0177 00984 Evoke am. In dia l74.5~|75,2 I760 more 6381—6091 6,929 Blake shoe sprlng Flee lengm ss 55 mole 2.|65 2.283 From axle Om din l5.0 M9 less 0 5905 0.586 From axle Band 005 wilhm 0.2 more so». ends supper! on 00078 v block, measure Fran! wheel mm mm: defleclion LO wilhln 3.0 more be” “"°"'°"’°" 00393 0.1la Front lire An pvessule 1‘5kg/cmz om ol 2|.330lb/in’ S'Mdavd I. Rear Wheel he 70 515mm Eeyulrl’ng Unlii 11mm; Final drlven sprocket Bottom diu. 145.76 M] less 5.738 5.696 Rear wheel hub Axial ploy 0.005 wllhln 0.1 more bearlhg 0.000195 0.00993 Radial play 001 70.02 0.05 more Hear axe dmehc. Overall Ienglh 73 0774.2 collar 2.905~2.921 Heor axle sleeve Overall lenglh 9.5797 0 374 70.38! Rear wheel axle om. dia. 16.9~I7,0 16.85 leis 0.665~0,669 0.663 Rear brake shoe Bend 0.05 wnhlh 02 more 0.0078 001. die 174171743 Cullev am. am, 0854-46362 Rear brake llhlng Thlckness 3.574 5 a 0 less 0137-4) l77 0.118 Rearbmke shoe sphng Free lehglh 27 as 92.0 mole 1.0976 1.259 Rear brake 02m Thlckness 11.9~I2.l 0 468~o 476 Rear brake pedal Foot wldlh 20790 on! of 0767441311 slundurd Rear wheel hm Lalerul dellecllon H! mm 3.0 more 0 0393 0181 Hear me An pressure 2.0 kg/(m! oul cl standard 28.44 lb/in2 MAINTENANCE STANDARDS,CB72 . 77 For maintenance operation For HONDA 250-300, Maimenance Standards, specification and dimenston are listed hereatter tor reterence. EXPLANA'I10N : Maintenance Items Items to be inspected, sen/ice-wise. Standard Value This indicates the manutacturer’s standard size or the standard size atter newly assembltng or adjusting, and shows the size-limit of completed part in the permissible limit at adjustment. Repairing Limit Unusable wear limit of 'parts requtring correction or replacement, tunction-wise. Remarks Unmarked numbers are run unit and inch unit shown underneath, and others accordtng to the untt indtcated. UNIT IN CHART : Unmarked numbers are m/m unit and inch untt shown underneath, and others according to the unit tndicated. CONTENTS I. GENERAL PERFORMANCE .. 2. ENGINE A. Cylinder, Cyiinder Head E. Crank Shaft, Connecling Rod, Piston C. Cam Shall, Valve, Cam Cham.. D. Upper, Under Crank Care E Ciutch, Crank Care Cover L/H F. Transmission G. Gear Change H. Kick, Crank Case Cover Fi/H I. Oil Pump, Oil Fillel ........ J. AC. Dynamo, Starling Molov , K. Contact Breaker 3. FFlAME .A. Handle ................... B. Fronl Cushion C. Steering Slem, Front Fender.. .. D. Fuei Tank E Frame Body F, Stand ,,,,,, G. Rear Fork, Fiear Fender. , , , H. Rear Cushion |. Fronl Wheel J. Rear Wheel K. Eieclric Equipmenl .................................. 19 19 21 24 26 27 25 so so so 32 32 33 33 35 36 36 37 38 35 39 40 MAINTENANCE STANDARDS (Model C372, C377) 1.. ms lm. me d'lmenslans wllhaul un'lts 'lrld'lcale '1 mm " [upper slepl and "lnch" (down slepl, and others actovding to me unils lndlcaled. Mark * ls excluswely used omy lar model 0577 and nlhers are common bolh mode‘ 0872 and C077. 1. GENERAL PERFORMANCE I l e m Slandzm Repelrlng lell I Remarks Compresslon pvessuve 10.5 kg,’(m2 a (kg/cm less Measure wurl klck 149 31lb/1n2 113.76 lb/in2 :qtl,‘ Consumpllan 45 ml 2 26km/ 6 less Speed 40km/h 127 Br m.p.g. 7: Br mpg 124mphl Compresslon relic 9.3~9.7 oul rlandard Lubr'lcaurlg o1l consump- 120 cc/IOOO km 200cc/ lion less 'IOOOkm more 120 cc/éZO mlle 200cc/ 620 ml‘e Lubricallng all capaclly 1500 cc - am standard Check wlth OII gauge Rear wheel nulpm Mrs more 12.575 less (Max. oulpull 18PS more IAPS less Caster 62‘ our standard (Refelemiul Va‘uel Trall 85° om rlnndard (Relerenllal valuel 2. ENGINE A. Cylinder, Cylinder Head l l e m Slandard ‘ Hepolrlng lell Remarks Cyl'lnder sleeve Dlllerence between WHHIU 0.01 0.05 more Aller barmg. rmnlng max inudia. md 0.0003 0.00196 shou‘d be emarced min, 1", dla. Cylmder slam In. d1a 54.00—54.01 54.10 mule Aller barlrlg. rmnmg 2.1259~2.1263 2.129 shomd be emarced 60 (JO—60.01 60.10 more 2.3622~2.3625 2366 Cyl'lnder barrel Helgm 83 45—935 001 slandard 3.235~3.681 Cy‘lnder s1eeve Out, L110 62 02—6203 lRalsrenlia‘ vo‘uc} 2 441 —2 442 67.02—67.03 2.638~2.6389 Wavmg space 0,02~o.os Be pressed mat lhe ,ono7a~o.om95 normal lemperalure 19 r t e 111 Standard Repalllng ler Remarks Cylinder Over Size 0.25 3 category at 0.25 luvolSlze‘ 0 0098 Cylinder head in. dia 419944201 42.06 more lCum shah bearing par 1,653.. l .653 1.355 Cylinder head in, d‘la 17.047015 17.05 mare (rocker arm p n 0.669~0.669 0.671 Cylinder heod Combustion chambel 29.3~29,7 ct [rocket arm pml capacity chrerertal nuluL“ Cylinder head Bend 0.03 less 0.03 more lanochlng lame) 0.001 0.002 Cylinder head Bend 0.03‘less 0.06 more (head (aver attaching 0.001 0.002 lace] Cylinder head at. dia 25.5 linlel part! 1003 Curburallor insulator Gap al the in, dla. 0.5 less 1.0 more or inlet porl 00133 0.039 Cylinder rend gasket Width l.o~l.l When lighting 0.03970043 Cylinder packing Width 0.34.4 When lighting 0.01 1870.0157 Tachometer gear in die. al Bush 7.077.015 7.2 more 027570.273 0 233 Tachometer gear Out, dla tf Bush 139827140 0 55070.551 Tachometer OCG' Tighln‘ess 0.4 Unless omission. “0" ring, uni/hi 0.015 there are no lmuhles Tachameler gear and Clearance ems—«0.043 02 more unless omission. bush 10011—00016 0.0078 there are no troubles Cylinder head cover Flatness 0.03 less 0.06 mare 0.001 0 002 Breather sield plate Thickness 1.0 0 0393 Breather sield plule Attaching dlreCllOn put lorward Be aarelul ol the an arraw mark . Cylinder head cover Tightmg torque 1.34.3 mekg l.9m-kg less a sporls are equal 3.74~15..53llg 13 74 it“; 2 tier head Cap Tighting torque 0.45 mrkg ygzwg res. 3.25fléb 253 "lb l' der head cap Did 3 2 2.5 lcic ' ring 0125 10984 20 B. crank Shafl, Cbnnec'lng Rod, Plslon I t e rn Slandard Repalrlng me Remarks Crank shah Comp. Crank ang1e (I 81 180" Crank ang1e {11 31 360' Sprocket, center crank Tooth 16 shatt Bottom dlo. 36.2857 36.2236 1.42654 ~ 1 .42857 Gear, center crank shah No. 01 1mm 22 sprocket Thtckness at cross 15.295~15.337 15.1 less No. 01 cross teeth 3 over teeth 0 60270.603 0.594 001. die. 47.9~48.U 47.7 lass 1.885~I.BB9 1.877 Out. 31a 38 003733.015 38 05 more 1,496] ~ I .4966 1.498 Radial clearance 000670.014 0.05 rnore Center crank weight 0111. G13. 01 ptn 25 991 725.999 25 95 10:5 1.0232~1.0235 1021 Center crank shah, 1". G10. 25.0725 02 0.00401 (Referenlicfl vu1uc1 pressed port 0984—0985 H Cmnk shah. bearmg In cm 25.907~25.921 purl 1.0194020 R crank shatt. peartng Gm (118. 29,983~29.993 29.95 tess part 11804711808 L179 Crank shah comp. Max. swing 003 1w 0.1 more 0,001 0.003 R crank shah key Wtdth 4.074 03 4.10 more grouve 0.157~0.158 0.151 Thtckness 4.074 1 [Retetenttat w. JO O.157~0.161 Length he processed [Releremia1 mum wtth one cutter L cronk rhutt pm, In. oia. 25.907~25.921 pressed part 1.019~I.DZD L crank shatt pressed Out. mo. 30 002730 015 25.95 less port 1.181_1186 1.021 x 30 004730.009 *2937 1c» 11812~11814 1.179 Prtmary drtve sprocket No. 01 tuctn 15 Measunng 39.11~39.21 38.9 less 21 1 r e m Standard Hepamng 1m Remarks O1Hil|er drwe sprocket No. cf mm 24 01, am. 250—25 01 2s 0 more 0.9842— 0 9849 1.023 Measuring bottom di 45.15~45.348 45 05 less 1.777~1.785 1.773 Cunnzcl‘mg rod mall 1n dia. 15.0M~15.043 15.1 more end 0.591 —0.592 0 594 Twist w1|hout002 0.1 mere 0.0007 0 0039 Conneclmg rod big end Tmokness 17 97— 18.03 17.5 1ess 0707—0709 0.888 ‘0 d‘a- 3LOM~3L015 31.04 more 1220— 1.221 1.222 Axia1 clearance 007—0 33 0.5 more 0.002~0,012 0.0196 Diagonal clearancc 0~0.00B 0.05 mule 0—0 0003 0.0019 \leedle mI‘er Our. d1o. 2.502—2.51 2.5 less 00985—00988 0.098 .engrh 13.45— 13 5 0.529— 0.531 \ln. read. 48 pcs ‘1ston pm Dul. din. 14.994'150 14.95 lets 0590—05905 0.588 Dvsml‘ ‘eflglh 45,?~46.1 (Refevemim 1:10: 1.807~1.814 51.9— 52.1 2.043— 2.051 ’mon heed >iu. 53.65—53] 53.8 1ess 2112~2.114 2.110 59.65—597 59.8 1ess 2.348~2.350 2 346 ‘islon 5km )ia. saver—54.0 53.9 1555 N lhe pin boss 2125—2128 2.122 611390001 direcrr 59.98—80 0 59.9 11:55 2.361 —2.392 2.358 ‘1s|on row in! slep outrs|andard )7 009—0 07 )-0.0023~0.002 xeCDnd step Measure at the )7 0124114 0055 diagona1 dlrectmn >70 001~o.005 EHime 0.14~o.1e outrs|andard Measure at 5 m. 0_005_0 005 10.1991 upper p1 [mm the float 0! 22 l l e m Smndmd Repairing lel Rem,“ Pls1on rlng gruuve Groove wmm 1 505~1.51 155 more (Topl 0 05927 0.0598 0.051 Pls1on rlng gruuve Groove wmm 1.505~1.52 1.55 more (Second) 0 05927 0.0595 0 061 Pls1on ring glam/e Groove wmm 2.805~2.62 295 male (Oil! 0.'IID~0.'|H 01161 Pls1on ring glanve Ou1 um 48.17452 479 less 1.893~I.fl97 1.885 53.37534 531 1953 2.095~‘2.102 2.090 Plslon & cyl'mdel Mm deurunce 0.06 mole 0.0023 Plslun overs‘lze 01155122 0 25 3 calegury a! 0 25 0.0095 1000981 uvevslze Plslun vlng (Topl wldm 1.4571116 1.4 less 0.057700574 0.0551 1.4571.465 1.4 less 0.057~0.0576 0.0551 Plslun ring (Second! Thlckness 2.4.4.5 2.2 |er die 88‘0~83,035 RClFrexmm mm: 3 464~3,4¢5 :Iurch cemev 1nd Axm deuru'vce 0‘027_o‘oo7 02 more mm’m‘ shah 0,00l~0.0026 0 0078 more C‘urch pressuve p‘ure Huvness whhm 0,! 03 morc 0.0039 0 m w B \n dwc 112 4,409 :‘mch Sprlng Frec \engm 314 32.4 \ess 1.314 |7275 Dwagsvaw’ degree Lo \css 20 move 0.0393 0 WM loud I53~157kg 13.5 kg ‘03‘ 33,73~34,6l || 29.988 ms Crank case SGvev LXH Homes: wi'hm 0.01 006 more 0.0003 0 0023 many (me rovPr L3H In. dvc 56A~5a046 Wan of 0H fiher) 2 253~2285 :mnr case covev L/I» Txghlness 0.5 more Dubsfiandur: 4’0“ Ymg> 0.0197 Crank (use covey U}- M mu l4.0~14 015 141 more Wan o4 smn spmdlcl 05.51-40.5518 0 555 Cvunk (use cover U}— Thwdmess n.3~o,4 When dwsossemb‘y (Padang) and mmmennnce, o 0118~o,0157 exzhmge should be Am;- earh m F. Transmlsslon ‘ , w , c m Svandard Repavmg lmm‘ Remarks Transmwssion Type Four speed ‘ Conx'am mesh gear ‘ Main shah ‘ Om dm 24 V59~24 98 24.9 has: 0 982~U 953 0.980 ‘ Main shah and M2 gear ‘ Ciearonca u 02~o 074 0.1 more 0 007~o 00291 0.0039 Mom shun Axm‘ CIeurunce o \~0,75 1.2 move ‘ 0 DC39~0.0295 0.0472 28 i | I 9 hi Slandavd Rapuiring Limili Ma 71 shall and M. gear Clearance oi rmury 0.034078 01 more direclion 1001187000307 0,0039 M1ss1on gear Bock rush 0.089~017B 0.2 male : 00035700070 0.007s Tap gear In 010. 113.048.0113 18.2 mnre 070970.709 0715 Top gear ll'ifier rod p01 in dia. 8.078.015 8.06 mare 0.314~0.315 0.317 Top geariBushl In. M. 20,540,521 20.6 more 0.5077 0.9079 0,811 Top gear 0031 and Cieamnee 0,031 0.1 mare [Pan 0! 20.510 mission shai. 0.00318 0.0039 Drive spmckel Bonom din, 55-549~55.775 547 less 1 2.5s4~2,589 2.547 Drive sprocket Ciemnee 0.034.079 0.25 more (Romy direction! i.00118~n 00307 0.00994 Counier shaii in, dm. 24.3744 335 24.4 more (gear sidei o.959~0.950 0.9505 Coumel snen 001. die 2496724339 24 9 less 098270.981 0.980 90511 14mm in. din, 1437544393 15.2 mare ‘ 0.565~0,566 0.599 1 om. dio 249345.013 ‘ 1 098370.984 Counts! shall and Clearance 01 [clury 001 70.098 0.2 more (:2 gear direeiiun 100039700038 . 0.0078 Low gear Crossover lhickness 21007721714 21 5 11:55 MES-«0.554 0-850 K1ck smflor Spind1e unc Clealcnce 0022—0052 0.15 mare bush 14mm 1.00086'000204 0.0059 Bush 0 14 mm om. dia, 17,094~17.112 1 17.05 less 0.672~0.673 ‘ 0.071 In. dm. 14.413~14.431 14.53 more 1 0.557~0 553 0.572 Mission gem gear raiio F1151 3.12 2nd 1.74 am 1.27 Tap 1.00 Kick spindle poie spring Flee iengih 14 13.5 1ess ‘ 0.551 0,531 1 1 29 — __—_——_' | i 1 . e m . 515mm ‘ Repumng Limll Remalks Kick spindle paia bush om. dia. ‘ 5 ‘ 4.5 lass pm 0.1% 0.177 Over-ll lengm is 12.5 iess 0.511 0.492 Primary chain Deflectmn 5— 10 20 more snow by max. swlng 0196—0393 . 0 7874 01 iaasmg R0lle15X6.25 Na. Reqd 12 pleces 6. Gear Change 1 r e n Slomaid Repalnnngmfl Remark L L Gear shiFI ion in. ma. 340-3405 34.2 more i.aas~1.339 1346 Gear shin drum our. ma. 33.95-33.93 33.9 less i.336~ 1.337 1.334 Drum and snih 1an Clearance 0.025~0.075 0.25 mara 0.00098~000295 000% Gear ananga pauai In di0. 17.0—17.027 17.3 more 0.609~0 070 “1681 H. chk, Crank case Cover Rm 1 r r. n Standard Repairing lew Remarks chk sinner gen snan Out. dia. 14341—14353 14.251ess 0 564~0.565 0.561 Kick smrwr gear and oiearanaa 0015—0104 0.3 mole cover iz/H 000062~000409 0.0118 Com R/H Harness wiihin 0.05 0.1 more 0.00196 0.0039 I. 011 Pump, Oil “Her 1 r .1 n 1 51:2an Repainngumw‘ Rammls i i on pump drive gear Teeth wrmn 4 1 0.157 Bend 0.05 0.1 more 0.00195 0.00393 ‘ on pump drive gear Back msh 0.005~0.127 0.15 more Adi-m by packing and M crank gear 0.00334~0.050 0.059 011 pump gear lop Claurunce 0025—005 0.1 more and inside wall 0.009s~0.0019 0.00393 30 I l e m Slandzrd ‘epalring Limil Remark: Oil pump pm Back rush 0106-4011 0.4 mare 0.0041770 0082 0.015 on pump gear slde Clearance 00470.089 0.1 more lace and ride (over 00015700035 0.00.39 on pump gear and pln Clearance 001370.05 0.3 mare 000051 14,0019 0.00113 Oll filrer snall and all Clearance 001270.048 0.1 more liller rotor 0.000472~0.00168 0.0039 oii filter rolor om, dla, 57 2.244 on lrller cnpln Loosing 5710 15 more Measure lne amp. 0196703937 0.5905 lilpde pl me cenler .l. A.C. Dynamo Starting Motor i 1 e m Slandard zepplrlng Lm Remarks Spark perlormenee on 3 Needle gap more 300 rpm. 7 less 3 Needle gap lgnllitm 0.3” 0.275 cnarglng perlprmance Charglng current 2.0~30A oul.slandur Slarl pl charglng, pl on dynnma 1700 Lp.m., aller lnel, al 500 me1 Dynamo slorler and Clearance 0.5 0.8 mare roler 0.0196 0.0314 Starllng elulcn outer Out, dla gap 070.06 01 mare and dynamo 070.00236 0.0039 cross mew 6x24 Tlgnling larque 0.5 mlg out-rlonder wnen llghling,scyew 3.61511 lb rock should be needed, clmch roller sprmg Free length 25731 24 less 0 9847 1.220 0944 Clmch roller Spring ln 010. 41 74.25 4.3 more lCupl 016170.167 0169 Our. dlz. 5.2~5.3 5.0 less 0.2047 70.2086 0196 Slarling sprocket oi 001. are 37.175~37.2 37.1 less clutch ouler iournul 1.463~1.464 1.460 Slarling melpr Valvuge 12v Horse power 0.4 KW out-rlonder Mag 30 sec onl-smndpr 31 Item Srandmd Repamng anl Remcvks ‘ Contact pmm Max. gap 035 oumundmm 0.01377 ‘ \gn'mon (Immg Crank angle belure upper 3° less dead pmm 7" more 5a Spark advancer R. P, M. 1100 r,p_m (5°! outsmndgrd ‘ advanced beglnmng Spark advance! R. P. M. 3300 1p m. (45“) outrstandard advanced finisn . Spark advancer Crank angle 40° 37°~43° \ advanced max. auI-range advanced ang‘e I v e m standard Repamng me Remarks . R .arburener Type FW22H 1 A40 * PW26 Main ‘91 if 100 a e; 135 AH I ‘ ‘ 80') X 4 A0 3 0mm Need‘e 1m 0.74:»:2 Jet neeme Zafidj 22402—2 step Cutter wuv * 24231—3 mp g 3 wmzn 1.2 kcumng depth 0 05. An screw it 2 nmnmg 1—1 ‘,r_i remrn k , 1% ram Slow 12! if 35 . 2 42 o 89') X 2mm x 4 5'09 32 K. Contact Breaker I I a m Standard REDHWJVQ er‘ Rammks Carburener Valve xem . 2.56 ‘ 204: Pm curler 12¢ newer jet # 150 Power air rer 4Q 90 3. FRAME BLOCK A. Handle | 1 e m srandard zepairing Limit Remark: chumfevence dnecnon May 4—8 oursmndurd Measure or our oi rnrome grip 0157—0314 cwcumievence )ifierence between Length 55 omslandavd outer and mner 06 2]“ “Home wire Clu'ch wne drrrerence Lengm 133 oursrandard be(ween auler and 5.236 Inner Cmrch lever Ploy 25—30 oursmndord Check by lever end 0.934—HB1 Brake lever P‘uy 15—25 outsiandavd 0.590~0.984 =ronr lurk cover (esion Thrckrer 6.5 6.0 less 0.255 0.236 39 = om. ma 1.535 B. Front Cushion | I e m Standard Repcv n9 me Rwrarls From cusmon Tvpe Te‘esrope wpe outsfiondo'd Snake 80 our srandard 3.149 on cupucily both of R. and L. aursrandard 250 cc From cushion spring Free \engrh 185.5 180 less Relerence value (Ore step] 7.303 7.036 33 l 1 a m Slanduvd Hepalrlrlg Lin Remarks ram cushlun spring Free lengm 221.5 2165 less nelerence value (Two siepl 8.720 8523 Overall lengm 407.0 396.0 less 16.024 15.590 Avallable wlndlng 32 N05. (Hm step) Avallable wlrldlng 30 Relerence value Nor. (Secondary slepl Helgm m coxe 374 nelerence value of blnd 14.724 Torque m case 24.1 kg Relerence value 01 bind 53 H lbr Overall wlndlng 62 slandar Nor. Dla. oi Cull 4.5 neierenee value 0177 CDlI am. dla. 25.0~25.5 0.9847 1 003 mm lerk plpE comp Bend. mm 01 0.15 mm The bend 0' P‘DE 0.0039 0,0059 nut. when made me plalmg pan 0 lulcrum you. lurk plpE puslan Om, dla 3745737475 37.4 less l.474~|.475 1,472 mm lurk valve In dlD. 32.93~33.019 33.1 male 1298-4299 1,303 mm lurk plpE pislon Space belween lnrk 0055-0.109 0.2 mm valve pipe 0.0021 70.0042 0 0075 F001 lace 051 002 oulesmndav degree 0.00075 mm {ml 1101le (use In. dla. 37.5~37.539 37.65 mars 1476-44779 1,482 Out. dla. 41236741275 41.15 1.623~l.625 1,620 less Von! lurk bottom Dlece ln. dlD 15,0~I5.043 15.1 more axis pen lFll 059070.592 0.594 mm lork nonom Dlece ln. dia. 20.0720 52 20.2 more axls pan (Ll 0.7874~0.807 0.795 eal houslng ballam ln. dID. 41.341362 41.5 more case Inlaying space 1,625~l.628 1.633 r l t a 7“ Standard Wing erntt1 Rmrlt: 4 Seal housing and 0“ In. (11:). 46.0—46.039 Jumtandard‘ seal 1.511~l.312 Inlaying space 0 (la—0.3 0 0023—1101 I Fork plpe guide Overall length 36 nut-standardl 1.417 1 In. die, 33 0—33.039 33.1 more 1.299— 1.300 1.303 Out. dlu. 31466—31491 aut—flandurd 1.475—1.476 Front lork upper Overall length 173.8—1742 out-standard e.842~6.658 Front lork upper Out. dlu. 42 (Upper part1 1.554 Front tom upper Out. dlu. 34.4—34.6 outrslandard (Cover cushion 1‘354~l.362 inlaylng part! In. dla, 33.2—334 substandard 1,3D7~1.314 anl lork under cover Overall length 175 6.889 Front lork under cover Out. dia. 54 lupper pun] 2.125 ln dia. 38.5 1.515 Fotk rib upper cover ln dla. 54.5—54.7 out.standarc in1aylng part 2.1454153. Fork rlb under cover Out. dia. 55 imaylng oort 2.155 ln dla. 35.1~38.3 1 499~L507 C. Steering Stem, Front Fender l t e rn Standard Emailing leil Remarks Stern and bottom cone Bindlng space 0007—0041 0.004 less 1 race ‘ Steering head stem nut Bindlng torque 6.5~7.5m.ltg 5m.kg less 47.01 —54.241!|b 36.16 it lb Steering stem top cone Out. d1u. 25 979—260 race lnlaying port 1.022~I.023 Sleerlng stem lronl Vork In. dia. 38.~38.062 38.25 more plpe 'trtluylng part 1.496~L495 1.505 35 Standard Hepomng me Remam Sleermg stem bollom Slopper angle 76° ourslandard Mausuvad by pg blldge (double, Hde (referential value} i 5 mm) Sleerlng lop con: race In dla 26.0—26.011 oulrslandard LOB—1.024 Fronl lender Plank 0.8 0.031 Malerlal SPCrl D. Fuel Tank 1 l e m Slandard Repairing Lvml Remavks Fuel tank Volume 14 e 3.asagulus Reserve l.2~l 5e <1,317~0.39sgulus E. Frame Body l l e 'u Slondord Repairing leu Remavks Head plpe comp top ball lcCe Head plpe comp hollow lace Sleel ball Steel ball lop Sleel ball bolmm Rear lurk center bush Binding space om. ma No. Reqd. No. Reqd. ln dla. Bmdmg span: 0.051 —(J.(1575 0 . 002—0. 0022 0,001 —(l.(lSl %r 0.009 18 pcs Wpcs 14.01—14.02 (1.55] —(l.55| (JAR—0,08 0,001 —(J.()()3 oulrslandard oulrslandard oulrslandard oulrslandard 14.1 more 0.555 36 I I e m Smndnvd Repamng Lmu Rem,“ Step arm comp. nu ma. 12.2 12.7 move 0.480 0 499 Step arm 11mg mm om. dia. 1e.957~16.9a4 167 1ess 06671-0568 0.657 Mam stand p1pe Th1ckness 2.3 0.090 Main stand the hole In. d‘m. 14.0~H,027 14.3 more 01 bmdmg pod 0.551 —0 552 0.552 Mam stand seltmg boH Out, am, 13 9— 13 968 13.5 less 0.547~0,549 0.531 Mam smnd semng spring Free 1engm 86 83 less 3.385 3.26 Land 875 be 55.20; less In case m binding, 192.937le W0 071 1b5 max. Stretch and 103d (referemicfl va1ue1 Broke pedal In. dia 17.0—17.027 172 more 0.669~0.67D 0 677 Cleavance 20—30 out-svandulc 0.787— 1.18 G. Rear Fork, Rear Fender 1 v e w Smndavd Repamng Llrm Rummy; {ear (ark pwm In. dla. 26.0—26.021 1.023~l.024 ?ear iork pwm bush Out. dia. 26.04—26.00 Aner pressed m 1025—1025 gwe (1 «mm much 10 the m. me In. am. 20.05~2o.oa 20.5 more 0789—0790 0.807 Pressed space 001 9—0 08 C1earance 00007—0003 agar 107k, pIVO! 0011 Out d1o. 13925—13968 13.8 1955 0.548~0.549 0 543 Ovemll 190901 301 'I 1.850 Dnve 00310 Type BK 530 Teeth 94 teeth Slack 9— 13 outrs1andarc 0.354~0,51 1 37 I I a m Stunduid Repairlrlngmll ”mks Rear brake stopper arm In. dla. 10.0-40.2 0.1 more 0397—0401 Thickness 9 oulrstandard 0.354 OveroII length 235 15.1571 H. Rear Cushion , I l e m I S'anduld Repalnng um FE-mkg ‘l" Rear cushion l Stroke I 60 nulrslandard 2.362 I Oil capacity 52 cc ‘ Dm-slandurd‘ : 60 spindIe OH I DecIIned Iehsmh 60—67kg/0 5m/s oulrslandard 13227—14170 I lbs/D Stu/s Rear Cushlon spring Free lengva ‘ 210 207 less In case at 135 mm 8.267 1 8.149 Ibihdmg highil I Load ‘ 37.519 , 3319 I255 . 7 283 02.6mm; I 72.76lbs I. Front Wheel | i g m 1 Syanduyd ‘ Repairing Limi)‘ Hemaiks Front axle di'slehce Overall length I 49.9—50.1 mllm 1.964~1.972 anl bran cam Thickness I 10 I B less I I 0.393 I 0.314 From brake Shae om dIu. i 199.8—200 I Shave out. din 7.856~7.874 I From broke Ilning Thickness 5 I 2.51ess I 0.196 I 0.093 Brako drum ta. dis 199.85~200.15 . 201 more I 7.566~7.B79 I 7.913 Brake shoe sphhg I Free length 63.0—63.5 66.5 more I 2.450~2.499 I 2.618 I Load 5 kg . 3.5 kg less 1n case ol 67.5mm I 11025“); ‘ 7.717Ibs I [setting length) Front axle . Out. die. I 14.9sé~14.9a4 I 14.9 has ‘ 2.657 I 0.589~D.589 0.586 I 35 II I 1 e m Smndnrd l lapalllng lel|‘ Remark anl axle Overall lenglll 235 9 370 Bend 0 05 0.2 nun 0.00019 0.007 From wheel vlm Swlng 1.0 3.0 more 0.0393 0.] l 8 Frnnl lire Dlmenslon 2.75~'|B 43R 0.105~0 708 Air pressure 1.7 kg/m2 om-rlondord 24.l74lb/‘l Frnnl panel axle ln. dlo 150715.015 15.1 mnre 059070.591 O 594 l l | 1. Rear Wheel I l e m Slnnduld l-pailing Um Remams Flnal drlven sprockel Bollom dla 151.8 1508 less 5.975 5.986 new axle dislunce Overall lenglh 10071002 oul.slundal tallur 3.997~3.944 Rear wheel axle Dul. dla 19947-4938 19.8 less 0.7B5~0.7E7 0780 Bend 0.05 0.2 mole Overall lengm 250 11.024 Rear brake shoe Oul. dla 199.8~200 Shave an die 7.866~7.B74 Hear brake Ilnlng Thlckrless 5 2.5 less 0.197 0.0984 Fleur wheel Hm Swmg 1.0 9.0 mom 0 0894 0.118 Real wheel lire Alr pressule 2.2 19/211? 81 284lb/m Dlmenslon 8 007 18 PR 0.11870 708 Rear brake panel axle In. 010 20 0720.039 201 0.7B7~0.769 0791 Rear bruk‘e panel lorql In ma 101~10.2 10.5 0 99870.402 0.41 Broke cm In 013. 15.0~15.043 15.3 0 591 70.592 0.602 39 K. Elec'rl: Equipments I , e m smdm Repaiving w Rwurks Head “gm bulb Elecmc current 35/30w zen 12V Stop lamp Elecmc cunam ‘I‘SW 0.56A Tau \ump E‘ecmc cunem aw 0.28A Serenwm leciifile 0mm volt DC 30v mm power Ac 40v Fhon pm" 95.405 pm 95 pm" Is: Adm. by‘screw :use Cupualy I SA 3auevy E‘sdro‘yfie capacny 0.79 nun-stander 0,154 9am comm IOAH m 12v when M ‘ charging, 104W \exs Speclfic grawy of |.2Au~1,2so me less electvoyie hop swuch \on. ampere we ZI\ Evoke 6—8 :ombmunon swirce \Aax. ampem 6A Wax. ampere d/\ nsulasim 50mm 1M!) \ess assismme loMn DAMA'Z \e; Speedometer Error —o+5% uuhsmndm- [achomeier 4000 (pm. ‘655 i700rpm uuLchndur- AUOC~6000 123$ anhsfunduv- aooc~aooo 12w aufirsmndm- 5000-40000 3:300 aut-sronduv- 1000C~12000 1400 our-smndo" 40 DISASSEMBLY AND ASSEMBLY In this chapter, mainly Disassembly operation was explained. and lor assembly special anenlion was only called lor where needed, as both operalion are similar, For item y! mi cla , ed ils model, il means each model is common. oncedure lor Disassembly operation & Procedure (or Assembiy operaiion Genevai and (ommon caution Toois 'l. 3. CONTENTS ENGINE (C72 .77} .09 m G. Engine replacement .......................................... Cylinder .................................................... L Cover Mission [Crank] ........................ Cylinder Head ... Oil Pump ............................ 2. ENGINE (2372 ~ 77) A. Engine Replacement . . E. Cylinder ............................ C. Engine Minor Overhaul. Assembly ....... FFlAME (C372 - 77] A. Rear Fork ............................ Front Fork . . 45 51 56 60 62 64 68 70 76 77 78 81 DISASSEMBLY AND ASSEMBLY 1. ENGINE (C72 - 77) A Engine Ropluomenr (I.. ride.) Dixcsxumbly 1. L. Exhaust pwpe ioi m nut 2 Assembly Tighten nm m leak ex Mons! gas, L. Exhausl pxpe muffler 3. L xlep hm 4. Gear change peda‘ Be camious or the posx- firm of seru'ion in case 01 mung Ase sembla wnn pumng in pusmon at the punch mark. Tightenr mg torque 2.1ka (154'. lb] meg angle, One seru- 1ion 'oreword in- clined hum hormone m pus‘mon. Premufian Tools mm. rocket wrench 14% rocket wrencn 17% spanner 14% spannel 10% spannev 45 Disassemhly Assembly Precmlon Tool! 5, L lrame dusl shield 6. Plug cop Air venl lube 7. Carburerler Fll securely selling nul s. Dreamer pipe Tightening Vorque 2.1kgm llSlr lb! Engine hanger ball Tighlening lorque mm [32“ lb) 46 10% spanner l 7"?” secler wrench 17% Spannel Precamion Disassombly Assembly Tools V. (Rusidel R. exhaust pipe ieim Tighten rml lo ueflk [om nul exhausl gas. Reler m L side H). R exhausl pipe mumev Reaer m L. side n. 5 ma bar Assemble wilh nuuing in posifion 00 me puncn marklighten- ing Imque 2.1kgm (15h. |bl Reler m L side 12‘ Starling more: cable 10% Spanner n Precuulion Disassembly Mumbly Tool; l3. Reiar in L slda l?- dust shleld T-Handls lorahead drlver (#GI 14. R. crank case cavar 15. ciuich wire 16. Drlva chalri ioln) Driva sprockei cover 48 T-Handle lorehaad drlvar (£31 10% sucker wrench Fora drlvar Pllers Disanunw Aslmbly “9&3?" 17. Chain ioinl C‘ip 18 Englne wiring :9. mg mp Ail vent tube ne‘er to L sue mummy mummy 20. Carburener settlng Se! lever oi iuel cup lull stop. 10% spanner 2L Engine hungni bah 22. Englne semng bolt 23 The palm of taking down engine 50 17%. mm wrench 17% spanner I45; socket wrench In case 0: mung. be cautious nut Io dam. age on Ihe from lender. I. Cylinder Disassembly Assembly “€31“ 'I. Condenser 9% mket wrench 2. Head (over Te lignlen selling mus Pay allemion lo mg on the head cover. color 0' "MS. follow alder as shown here and [spell 2 le a lime: la lighlell securely. 1mg mekel wrench (.132) @‘awhlle nul ©©®®Hyellow n... 3. Corn chain lensionel 1:. Spllking plug 10% suckel wlench Plug reekel menen 51 Dlxumnuy humbly “Tia?" 676. mu Steenng mp cone mce bnx wmnch Com chain Tighlening torque m case 0| diwxsembly 21ka (15". lb] and filling of lhe cam cham. be cave- fu‘ not to drop clip inlo the cylinder head. Pliers Tie a wue a the end 0! chain to pvevent chain 1mm dmpping mm the cy‘inder Hg. 26 h u _\ < ”H.7m -mq.._—_.. Fmingdivection 91 cup. m the [aim to the direclion ol revaluV (ion 0! Ihe crank I 52 Dlmss-mbly mm,” PleTcgglelon Combmahan pmcess r1 ‘ Coincide ”T" punch mark on me dynamo mm! with Ihe arrow mark on the stunar. 1m spanne! ® Cmnmde punch mark on lhe nghl mom surluce or me cum spvuckel comV plelewxlh tha center hne ol the cyhnder head. and combine sprocket a! crank 5'12“ by chain 6. Cylinder head Belovehand, vulva rocker arm, cam sham and valve should be subussem- bled. Plastic hammer F 0 altenfion I0 ring and gasket 53 Precuulion Disunambly Mommy “ml; 7‘ Cylinder In setting the cylinder on the piston. divide piston rings in 3 portssepamtelyand pulths ring letamer on the piston and Plaslic hummer push in the cylinder laying the stapper between piston and Case. Cylinder Ful in knock pin and packing securely Pislen Use new piston pin clips, avoiding such clips lost elaslicily. Thin nose phels ln usxemblying piston, pm the punch mork on the head ol piston to the lure- ward dilecllon, 54 D. My ‘ Hy Pracaullon Tank m fining the pistonbe carelul on selection of clearanzc with cylinder previously. It the cylinder is over-sired, select piston fumble kt this cylinder and assem- ble. . . we“. ___M._Ji 9. piston ring After setting rings 0.. the piston. check to avoid any hooking between ring and piston. In lining rings. be :ulefui upper and lower surface at the rings. lGenemlly on “I8 "we! surface maker's puncn mam is shown 1 Fig. 35 In case at using over sized cylinder. use o ring filmbla with the :vlinder. 55 C. |.. Disassunbly Asxambiy PreTceaglisinn 1. L cover In mm L covey. be Fucking careful the oil Nlel Dowei nin cover not in bite on a dowel pin 0! TrHandle lurehead Ihe oii inter shun driver (#3. 10% racket wvench Plastic hammer Fig. :5 2. Oil {me Set ail liner drive sprocket pin lacing l. outward. 3. Lock msnei Forehead drivel Plastic hummer 4. A Lock nut Aiter tightening per “ lectly. Ium up Ihe torque oi lock wash~ er. It not iquue and nut coincided. nul shouid be iocked alter Iuming to the lightening direction without loosing il. 55 Dlnsmlbly Mammy Preuution Tools 5. Cluldl pressure plate 5. Clutch litter ioinl piece 7. 2591. sel ring 5. Clutch center To tighten plme selling balls. lighlen tltetn evenly. dilgnnllly as shown in the picture. Check ex- lslence at spring. tn assembly, check up- emliotl at all melal guide. Be “legit about cripple 10%, socket wrenm snu'p ting ll‘movcl 57 x E Hg 47 9. mummy mum p‘ate CMch mcmn disc disc 10. em spindle smfl dmm stopper smfl dmm stopper guide 53 Pay anemionlm order aide! of limng. ae curefm about size. Precnufiian Tools In disassemb‘Y and .assembly. do il perpendicdany m the Crankshull and "an; misswan mam shah 10% sncket wrench 17% socket wrench Dnsammbly A‘smbw ”21:23:“ m ngmening slapper b0" 0' lick s‘aner. me malk on the end a! kick smner spindle shomd be seen Imough me hale. D. R Cover Dlmssamhlv Mammy Precaulion Tonls 'l. smting mam cablg 10% mum 2. Stuning mm R. L ride cover T+Iundle Iarehead dviver (#2) 3. Surfing mam IO‘L sacke| wrench Neutnl swimh 60 Pveccuhon 0605557“be Assemb‘y [00's 5. A.c. dynamo Alter starter assem- flur'el bled. check [ovation ol the starter sprocket. 10% rocket wtench 6. A.C dynamo Rover 14% rocket wrench Plastic hammer Dynamo rotor puller 17% spanner 7. Starring sprackel stopper 10% sacks! wrencl‘ Plastic hammer forehead drlver B. Slunel smacks fig. 56 '1 '0 61 E Mlnlon (Crank) Dime-My Assembly Precaman Tcolx 1. upper crank cos: Senlng nut Under crank case semd nu! & boll Under crank case \ 4. Main slmfl 52 In Ilghlenlng nm and bolt Inflow order as shown In figure starving «rampomry llghlenlng and man ucmul Ilghlanlng. 14% socket wrench 10% rocket “and: 141. rocket wrench Flasllc Mme, . . Prmuviou Duassambly Assembly Tm" Cnunlel shall To gal bearing oil seal do iI securely. Paint liquid picking on me case. Mme: lease the sur- luce of packing be have painling. non'l use with unuching cleansmg oil or Paim wilhaul chuk- ing oil holes. 63 I, Cylinder Head Dlsunembly Assembly PrrTrarliion co 5 1. Cylinder head can 23% spam. 27‘ Comm brcuker T-Handla forehead driver (#21 3 R.L. cylinder head ride cover T-Handla lovehead driver i531 Tuppér adiushng screw 10% spanner Tappel adlusllng sock. at wrench 64 ‘ Disaeenbry Mammy \ Prgfgg‘lsion 5. Valve Aflugh iug on L and R. valves not to be nnxed each other. Valve Irner Thin nose pliers s. Rocker arm crank rn assembly rock arm "r" crank prn, pay unen- Ramr mm mm to outer dram ate! a! me rocker arm crank pin and Rocker arm crank pin of exhaust rocker eXNOVOI am pm to msen inside me syrinder head. Farmer pin rs larger man diamr Hg. 57 eler or that ol the \atter. Cuttingrgmavesomhe rockerarm crank pin at Ma pinces are set for oil passage and retreat cur stud ban, So need sper c'wu‘ auenmn m ul- “mm pin to assem- Me. 7. Cam shah \ock nut Folehead dliver Flame hammer 65 PIECUV'IOH Disassembly AmmHV Taals 3. R cum shah Fovshead dnver P‘ashc hammer Assembty pmcess a! L cam shah After comciding splmyuv the red line of the point shall cum on the punched marl Plastic hammer of Ihe cam sprocket ((ucing Upward] then msen. Cam shalt \ock nu! L cam shah 10% vockel wvench a 10 ,I In assetnhty the cam shah , :omcide the spot where (:10th 0| splme ol the cum sprocket comp‘ete .5 lacking wtth the cor- responding spm on the cum shall and men mserl 66 Disassmbly humbly Pvemuflon Too‘s II. Cam sprocket comp. Pul lhe punched mark upward and cum shah rocker ml! to lhe rlgh| sids‘ Valve sheen cuner e. on Pump Dvsnssembly Assemb‘v mans?" 0" Pump svamer Oil pump packmg a CH receiver 01‘ pump body Fig. 79 2. oil pumg mung A Dowe‘ pm Check smoom w-mmg 9' rhe drwe gen» Swap mg Yen ,c, 69 Disassembly Ammw Prezauvion Tools Slda cover 5. on pump rlda cover dowel pin on pump gear A on pump gear a on pump drlva gem Refer Jo ma englna minnr avarhaul and assembly T»Humla drlver ($31 lorahaad Fly. 52 2. ENGINE (C572 - 77) A. Englno roplflcnment Dlxassembly Axsemb‘y "$5512“ 'I. (Ls'lde) Dual seal 14",. Spanner 7. Fuel rank semng ball 10% sockev wrench rig, EA Take out lube: A and a sloppmg (who. 3 Gaul :hangc ln assembly We slep pedal bar, commde Me Svep 0w punched mark wwlh hue cl We bvackel 1W», sxkel wre'vch 1w, Spanner 7D Dlmamhly 1 Assembly Precaulinn MI. 4. L. exhaust pm: ioinl mu L. exhaust mufiler 6. Speed-vachomerer cable 10% socke! wrench 1A7; socw wyench. 14% Spanner [21 17% spanner Fig. 90 Pncouvion mmummy Assammy Tom 7. L uwr cleaner cover 5mm mover cable 10%. Spanner A” (\euner conned- Ving Vube 7mm: We never .0 L. s'wdel T-Hundle Fovehead dr'wer {5:21 9. Engine samng boh l7'%. socks} wrench IO. 3 n2. sidcl Evoke pedal ; Shep bay ,: Slop switch ’1 was sockzl wrench ‘ Reler m L, side 5 72 !' ; ; / .i Dimuembly Assembly Plecaulion Tanll II. n. exh-usl pipe ioinI nu! R exhlusl muffler 12 Dynamo cove! 13. R. cmnk care cove! C1u|ch wlre Drlvespvockm cover 14. Drive (hcin 10% rocket wrench 14%. n 14% spunnev Reler to L. ride TrHumfle laveheud dvlvcr (5m TrHandkz (orehead dviver ‘53) Forehead driver Fllevs Refer m the item a! name. 73 Dimunnbiy Axsmibly 15. Air cleaner case 16. Thmule wire 17. Aircleanei cannecl- Ing tub: 18. Englne wlrlng 74 Precauiiun Tunis Ahnul lhmnle wile lever to Ihe imn oi Englna Replnoe- menl for Model CB 72. 77 TrHundle Iarehead dlivel (£21 / Disasxembw Assembly Premni ion roars 15. Comm breaker cover Cuman breaker 20. Engine hunger boll 2|. Engine senlng boll I 7”); sucker wrench 17% spanner Fig 10] Insert T-Handla lore- head driver. Take our Ihe lamer driver Ind lay dawn engine to take out the lunar drlver. 14% spanner WA, rockel wrench 17% spanner 3. Cylinder Dimsmhiy humbly PraTcouDuLion L Carburehai 10% spanner 2. Cylinder head cover Cam chain isnsioner Reler la Mode] C72 77 Engine Replace- msni. c Englna minor overhaul and assembly Dixossmbry Assembly ”21:33:30" 1. n L Cyhnder head ride com TrHundls lorehead driver (#3) 3 FRAME (c372 - 77) A. Hear Fork Flg. 101 Dimu-mhly Anembly ”‘13:?" 1. Rear brake wlra Com”- 14% spanner 2. Hear broke snapper arm Pliers 3. Cone: Pi" Axle nul Rear wheel axle wx. spanner Pliers Plastic "(mm a Dixussembly Assembly ”$233130" 5. Drlve chum .1 a Red. wheel 7. Chain case was. spanner 10% sockel wrench B. R. real cushion I7 X rocket wrench 17% spanner Fly. “1 Discuautly Exhaust mumeu cnange pedll Emke pedll Step bar R. new bar bmckel L. slap bar brackel Bu Precaufion Amnmy mm In usembly, pm me screwed ride 0! the tear cushian undel hon ho‘e m lace nulwlrd. Rele! Ia me previoucly menlinned ital- nl Engine Repla’cemenL 17% socket wrench 17% mckel wrench Plasflc hammer 3. Front fovk\ ere Harness lam?- nul 4. szedamelel cable Tachometer cubla Pliers B1 D‘wwssambly “my ”19:3?" 1. Had lium T-Handl: forehead driver (#2! 2. WIrIng Draw out only whlle. redund blue wlres. 3. Fiv. 113 Fly. 122 Dimmmbly Assembly "fig?" 5. Brake wlra 14% spanner 5. From brake stoppev arm 7. Speedommr cable uss'y 82 Flaflic hammer Forehead drlva Pllers \ . Prammion noossembly As5'5"“)! Tools 3. Collar pin (3 x 281 Front wheel axle nut Fllers 9. From wheel axle 1a From fork comp. From lender ll. Smner swltch as; y 23% rocket wrench wan. spanner Plasllc hummel 10% spanner H-handle lorehead drlver (#21 83 Dis/assembly Assmfl,’ “caisson 12 Throttle grlp plps 1-Humfle lorahsad drlver [#2, 13. Throma wlre comn‘ 14% spnnne 14. Clutch wlra Comp‘ From brake wlra comp. Clutch wlrs adiuu bolt. lelng nut Pllars I5. Snap pln 6% Slserlng damper‘ uock sprlng nut spflng iPluve . , Frlctlon dlrk Flg. 130 We“ 84 D‘ucuunibly humbly "'77:?" 1$ Hex. hall 8X 30 In assembly. pay anon- Sieering handle pipe Non on punched comp m E i 111% Socket wrench [ 17. Sieering damper knob compr [lock sprlng Dumper lack sprlng sei bolt. 17% rocket wrench 18. Speedomelar my 19. From iork hall Sieering head sen. nul. Siam nut 26% spanner 35% spanner 85 Preea re" Dimsxembly Assemblv Tonal; Fork lop hrldge Fla. 135 Sieerlng head ihreod camp. Sieering mp coin "ICE Siaerlng sun comp. 86 Discuembly mm” Pagan?" E. From lender Take out an armw marked bo‘l. 24. mm lurk comp, Pul lhe lmnl lurk under cover with welded clip as m I ride. Flg. In CONSTRUCTION CONTENTS DIFFERENCE BETWEEN C72 ~ 77 8. C872 ' 77 A. Engine 93 B. Frame... 93 ENGINE A. Mcln Paris or Englne 95 B. Lubricating Syslem “““ . 97 c. cenlrilugal OII Filler ................ 99 POWER TRANSMISSION A. Clutch and Fr'lmuly Chum ............. . I00 B. Transmission Svslem 103 c. Fl'nul Dnve Mechanlsm ........................................ I09 AUXILIARY PARTS A. Funnel Type Breather ....................................... IIo B. Kick Slurler Mechanism .................................... I10 (2. Cum Chul’n Tensloner ...................................... III CARBURETTOR ................................................ 113 FRAME ........................................................ H8 SUSPENSION A. Front Wheel Suspension ...................................... I20 E. Rear Wheel Suspension ..................................... I2I STEERING SYSTEM A. Handle , 123 a. Sveering ,,,,,, . 124 BRAKE INSTALLATION WHEEL A Front Wheel ....... 128 a. Rear Wheel . I29 AUXILIARY EQUIPMENT A. Air Cleaner ................................................ I3I B. Mulfler .................................................... 132 CONSTRUCTION 'I. POINTS OF CONSTRUCTIONAL DIFFERENCE BETWEEN HONDA 250, 300 MODEL C72, 77 AND C372, 77 Honda 250, 300 Super Sport Model C872, 77 has a newly designed chassis equipped With engine whlch partly reconstructed Irom those of Model C72, 77, and aimed mainly to be used as sports car maintaining availability as racer interchanging some ol ‘its parts. As this engine is high rotation high power type and chassis is light weight, high rigidity type, the special constructional teaturer comparing with Model C72, 77 could be cited as tollow A. Engine 1. Twin carburettor To raise horse power adopted Twm carburettor system removtrig iunction of suction manifold. Reciprocating change Change control system suitable tor high speed running and racing. Kick of forward step Considering relation With (tame direction at step at kick arm was set forwardu 180 degree [l-Typel crank angle To get stability at high speed reducing Vlb'GIlOl’l lelt and right crank arm angle was set as l80 degrees Frame Frame and rear fork of sleel Iubing To attain light weight and raise rigidity mu'ln constructional member is canslrucled by high carbon steel pipes. Telescopic type torlc To raise stability at high speed running on rough road maintaining rigidity, telescopic type Iork was adopled on the tram wheel suspension. Rear cushion of three step udiusrmem Rear cushion is adtustctble according to load and road condition. l8 inch type To enlarge bunk angle and to help pleasant teeling on rough road, equipped w'lln lronl wheel 2.7548, and rectr wheel 300-13 93 44“-_.7_ ‘ 5. Speed TachomeOer Speedometer and Tachomever were sev in the same case. 6. Step and handle easy to move or interchange To make easy ridmg poslure suwuble ‘or generu‘, hxgh speed or race riding MEMO 94 2. A. ENGINE Main parts of engine Cylinder and Cylinder Head are the most important parts of engine and to: construction, material and its machining rate of precision attect engine performance. This type of engine adopted most suitabie O.H.V type valve arrangement to attain efficient combustion chamber iorm On the other hand the (am shaft is set in the cyiinder head anathe vuivesarc actuated by iocker arm (OVH.C.t, accordingiy reciprocating parts are reduced very much comparing with other types, / Q) Conlucl breaker fitting hate LI) Cain shalt (2) oil ielt L2) Cant shait t'lyrwheei @i Breakev arm (a) Can sprocket (D Paints @ Vaive rocket mm {5) Teiminal © Vaive Spring 63) Piston :7, Screw to fix contact poini ® Connecting rad ® Contact poinl Cam chain Crankshaft Fig. 24. 95 The com shah is drtven by chain through the timth gear reducttoned 1/2 As the cyltnder head ts made of Itght oHoy, not anty rt ts ttght bu) coolmg ematencyts excetlent as heat conductivtty ts good, and shape at combustton chamber ts ideut semi-sphericat one to get eif‘tc‘tent combustton at mtxture and atsa to attain larger compression ratio As the cylmdev rs machtned wuh htgh rate at arectsian caolrng emciency and lubriculton are favorable, accordingly weartng chect IS very smatt. srngte raw wetyae needle beov'trtg is used at the big end at the connecting rod to get ample loading capacity at the bearrng On the other hand stngte row baH beartngs are used on the crankshatt, where W~type rn'tddlo parts at 2 stattons singte row the needle bearing are used to get larger toadrng capacr‘ty. A: crankshaft has an tmportant tuncttan to convert reciprocattng motion to rotation, tnertta torce due to rce‘rpracattng matron at ptston and eonnecttng rod shautd be reduced by putttng batance wetght to get smooth revotutton. The crankshaft can rotate smooth runntng as tt t5 batanced by dynumtc batance an the bolunclng rnaetrtne ether camptete maehintng. To reduce vrbrat'ton at htgh Speed revotutron 0nd to get stabrhtv at htght speed running the right and left crank arm ang‘e or' Model CB72t C5774 crankshaft is set 180 degree. LFor Mode‘ C72, C77 typo angle is 360 degree) Fig. 2 2. Type: crunkshah Prstan RoHer bearing Connecting rod R crankshatt e205 Z saecrat buH beormg , Cam (ham sprocket L cronkshufl , on pump dvive gear Fig. 24, Type“ erankshatt 96 Lubricating system ConsOrucHon and operand" For Honda 250, 300 an is supphed under pressure by gear pump and we'esump syslem ‘is emailed The on pump is anacned under crankcase by a bohs. The on pump is shown in Fig. 275 and (H is dliving gear and (2) driven gear, Power ‘is transmitted by driymg gear m meshing wun crankshah gear. As (or operanon of gear pump, me driving gear HI romies ra me arrow direciion and ihe driven gear 1'2I romves caunrerwise, men degree oi vacuum increases on lhe righi side sucking on from Ohis side in feed the left Side. Thereiare each pan oi the pump should be carequy inspecied ia ayaid engine burning or ooher iroubles due io mulelubncahon. Such lvoub‘es after occur due to oil leakage inrougn inadequave gap beiween gear ieein and pump main body, or aerween gear iace and pump body or pump side (over Causing drop of degree oi vacuum. Lubrrcoirng oil sumped in ihe crankcase IS Sucked by o‘il pump to pass ihrough the Fig, 2—4, Lubricating eucuianan Under (use I J. 7 , L‘ cover % OH my I ' x 4 . , 7 i M‘sslon shah Cy‘inder head Upper case [ l l" Mission gear Locker arm shah ‘ Cyankshufl if , 7 l , 7 L Cam shofl Connecling ma lug end Connechng rod 5qu end i , > OH sump ‘ 7a Forced lubricar'mg \ine . Splash lubricaving Ime (4) OH pump body (D Dr‘we gear (2) on pump gear (dnvmg gem! i 6) on pump side cover @ on pump gear ldrwmg 95cm «Q Fig. 275. 9B C. under crankcase and L. crankcase cover then the pipe line in splitted ta 2-ways, one to the oil filter. Oll cleaned in the oil filter is leeded to the crankcase where the line is splitted again to 2-wuys, one is guided to the crunkshntt through the center bearing and lubricate the big encl ol connecting rod and also the small end by splashingt and another line is guided up to the cylinder head along the cylinder stud bolls tram the upper crank. case to lubricate cam shaft and locker arm separately in the front and rear rocker arm in the head then drop in the crankcase lhrough the space around the cam chain. On the other hand, one line splitted tn the L, crankcase cover Is gutded into the transmission mainshalt through the Oll guide metal which is fixed on the L crankcase cover by spring, and then drop tn the crankcase lubricating mission gear through oil hale bored in the shalt, Cenlrifugal oil filter Oll filter is located on the front side of L. crankcase cover and oil is cleaned and separated by centrtlual lorce driven by the drive sprocket ol the crankshalt and chain, (1) Oil nlter ratar 2" Oil lilter shalt (z) Rotor cap Cl Filter shalt stopper Dln ® 52 mm circlip fig. 24). 99 . A 3. POWER TRANSMISSION ‘ Power iransmission is defined such mechanism as relation ol crankshafl is lrunsmilled lo rear wheel. The firsl slep of lransmission lrom crankshall lo ciuich is done by chain. This ciulch is wei mulliple piale lype, so ihere is no heat generoied by lriclion and also i no noise perlecily. i As ”US iransniission is such type ol advance 4-siep and conslunl meshing. ihere is no i gear sound while in gear changing, and consequenlly made ii possible '0 Widen rear wheel driving power oi powerlul engine. Furlher power is lransmiiied lo the rear wheel sprocker by chain drive from ihe mission, I and through rear wheel damper ol rubber made is ihe rear wheel sprockel and ihe rear wheel iorque is‘iiansmined berween lhe linai driven liange. So lhai lorque is lransmilled very Smoolhly wilhoul chain knock geriing smooih running. Especially as cluich is located on lhe mission shall, made n possible lo minimize deflechon of crankshall and also io slabilize clulch lunclion reducing cluich inerlic. ‘ A. Cluklu and primary :huin Clutch iii Funcrion and kinds Funclion ol clurch is lo cut or engage power lransmission in case of changing gear or srariing iocal‘ion belween lhe engine and ihe iransmissioh mechanism. Therelole fineness of culling and smooihness of engaging and disengaging are imporlanl leaiure. There are several kinds or clulch syslem as cone clinch, ceninrugai ‘cluich, multiple piare ciuich and single clurch, and we call wei type when merged in oil and dry syslem when oil is not used inside i2l Eonilrucilon and lunclion For Honda 250, 300 we odopied lype ol wel mulliple piale clulch. As shown in Fig. 3*] (disassembled Figure) and Figs 3—2 lcross seclional figure), inere is clulch ouler compieie when crankcase cover is iaken oui. in ihe ciuich ouler eanipieie, ciuich Spring (10) in sel by 4 0! 6X24 hexagonal bolls pressing clinch pressure plale (9| and sandwilching clulch friciian disc (6) by ciulch piaie (7). inside of rhe clinch piaie Ieelh are cur which mesh wilh ihai ol ouler purl ol ciuich cenler 181, and lhe cluich ceriler 'is connecled wiih ihe lransmission mainshali by spline and roraies wiih (7), (BI and (9i as a whole with lhe ironsmission mainshcll. 100 ®@@@®@®® L. crankcase cover Clutch piessure piate ® 6X19 washer L. crankcase (over packing o\ Clutch spring ® 14257 Oil seei Oil hirer cover In; Ciureh iirter term piece ® 5x24 Hex. bait 57x3 04mg [2) Oil guide metei pin (gt 6X74 cross head screw Ciutch auter camp. (:35 Oil guide metal @ 6X10 cross head screw Clutch friction dis: 3; OII guide metoi spring 6}; sxAé cross head screw Clutch piate is) 25",”, circhp @ 6x35 cross head screw Clutch center 17 L. ieg sealed lower boit @ 6X16 cross head screw Fig. 3-1. Disassembied ptciure of dutch On the other hand, with the groove cut oiong the outer perimeter of clutch outer, the clutch friction disc is connected through flange muting wtth said groove, and the transmission mainshuft can rotate ireciy. Therefore in case oi disengaging clutch, (9| (6) (7) 16! l7i (6) (7] (6} (7) (8) and 15] are pressed by ciutch springs, rotating power of crank is transmitted to the Mission as a wheie by friction. 10‘ Nola : Inside ol the clutch outer, the primary driven sprocket is lixed by rivetting and as primary chain is set on this sprocket, power ls transmitted to the transmission main shalt through the primary chain lmm the crank. Handle the clutch lever, the clutch Iilter thread turns right by clutch wire. and the Iilter threod is pushed put inside by the screw inside of clutch adjuster lixed on the H crankcase and push outside the clutch lilter piece [ll] through clutch lilter rod. As the clutch pressure plate 191 is pushed on side by the clutch Iilter ioini piece. clutch spring (101 is compressed to iree 161 171 M each 4 pieces. Therelore rotation 01 (5] 161 (6! 161 161 is not transmitted to (B). Numhel ol clutch plate and clutch lriction disc 15 loul sheet each lor Model C72 and 5 sheels each for Model C77. C377, 77. 0, Clutch plate (2 Clutch spring ”(mm/my =5! 1 6} Clutch outer buss ® Clutch lilter rod @ 6mm bolt Clutch iriction disc ® Clutch lever a) Clutch center ® Primary driven sprocket ® Clutch Niel thread (5: Clutch Iilter ioinl piece at 6mm rivet 6% Clutch adiuster (G, 25mm circlip @ Mission rholt (E R clunkcase cover Flg. 3*2. Crass Section al clutch lor Model C72 l0? @ @@®®@© Clutch lriction disc (9 Clutch pressure plate 0 Clutch lilter rod L. crankcase cover @ Clutch center ® Clutch lever 5x19 washer ® Clutch pluie @ Clutcti lilter thread 6x24 Hex. bolt ® Primary driven sprocket 65, Clutch odiusier Clutch spring @ 6mm rivet R crankcase cover Clutch iiiter ioim piece ® Clutch outer on guide metal ® Mission sholi Fig. 3—3. CI'OSSVSBCUOVI of clutch (or Model C77, C872, 77 Transmission system Function and kinds Following clutch. iuncilon of transmission is to convey power transmission. and convert torque by means of meshing geors ol dllierent number ol teeth. As shown in Fig. 3—4 il driving gear is smaller 1hun driven gear, No. of rotation of the driven side will be smaller transmitting large torque. Here it is called reduction ratio showmg the rotlo oi each gear numbers. There are two systems oi gear meshing lor transmission ol aulorbicycle Le. selective sliding system and constant meshing. 103 > O ) 2 Reduction ratio: . Torque ratio: bin: m Driven goar Drive gear (No. oi teeth B} (No. or teeth A) Fig. 34. Relation between reduction ratio and torque ratio By selective sliding system. shitt gear is siided by gear shiit iork to get adequate reduction ratio by changing gear to be meshed, and by constant meshing system, each gear can be rotated ireely aiways each gear in meshing state, and can be changed reduction ratio by actuating optional gear by means at speciai ciutch. Fig. 375. Crosssectionai ligure at transmission gear 2. Construction and function The transmission system at Honda 250- 300 is constant mesh and advance 4 stage rotary type. In Fig. 3—5 to Fig 3—9, neutral. irrst. second, third and to stage are shown. Function oi transmission as shown in Fig. 3—5 and Fig. 3—10 is as tollows, that is power rs transmitted lrom crankshafl to primary drive chain, clutch omer, clutch cenlel and llansmissinn. 1W LWM Fig. 376. The first Fig. 3—7. The mend Expiaining in order, from me crank rotation rs transmitted to the clutch, and me iransm‘rssr’on s‘rruh IS rotated to turn the low gear 17). The low gear turns sliding over the kick starter spindle (19L ‘5 the counter shafl 2 gear 191 which is connected with the spline 105 on the counter shah complete can move ireeiy axiauy, move this In the 1ett side by gear shift fork to mate with low gear (Hg. 3—61 then the low gear combines with the counter shafl as one body to transmit power to the top gear (12). Here the axial movement of mainshan gear is restricted by the gear cotter 1141 and the set ring (15) but not restricted rotationaHy. tsimi|qr|y counter shaft 3 gear (11) Fig. sea. The third I Ell (TV' l_1_ Fig. 347. The fourth tTop] 106 14mm bush Kick spindle melcll push Clutch lilter rad complete 12,5x21 ”O" ring Transmissian mainsnalt Counter shalt l20Tt Law gear complete Mainshalt deul Counter shalt zegeai Main shalt 3.gear Counter shalt Segecl Top gear complete Drive sprocket l5T Gear cotter 33mm set ring Drive sprocket fixing plate Hmm bush C Primary drive chain (DK328.56L1 Kick starter spindle Kick spindle pawl Kick Spindle spring Kick spindle push pin Ball bearing 6305 HS Ball bearing 6206 HS Roller 5x615 Oil seal 30628 Oil seal l4257 r22; Oil seal 5216 TC Hex, boll éxlz @@()®(—7 @ )®=}’4 {@2681 @©@®@®( 3;» @® Similarly tor the second, protrusion oi malnshatt 3 gear liOl cambine with that at moinshatt 2 gear l8] by actuating another shill lark and power is transmitted by rotating mainshait 2 gear (8) connected by protrusion with mainshalt 3 gear (l0l mounted on the spline oi mainshah transmitting to counter gear (3) and by spline irom counter shaft to the top gear. As for the third protrusion of counter shalt 2 gear 49t combine with that at counter shalt 3 gear llll to transmit power to the top gear (12) through counter shalt la). Arid for the top, mainshalt 3 gear (lot combine with the protrusion of the tap gear and rotation at mainshatt is transmitted straightly to the drive sprocket to drive the drive chain, As tor the neutral, each protrusion is not combined so power IS not transfer to the top gear Other parts of the kick starter system are kick spindle pawl 00) and kick spindle pawl spring 1211‘ This pawl males with the wards groove of the low gear to rotate low gear, When not kicked, the head part 06 this pawl is pushed by protruded part inside crankcase, arid pawl is pulled in to tree the gear. .t r Neutral switch assembly Gear shift fork Gear shilt fork guide pin Gen! shin iork roller Gear shift drum Shirt drum stopper guide eemaieie Shiit drum stopper complete Strit't drum stopper spring ' Shitt drum setting plate J Gear shift spindie complete Gear Shift amt complete Shflt arm spnng Shin arrn spring pm Gear shrli return spring Shitt return spring pin Shift fork rod Gear change pedal Change pedai rubber Stopper arm setting bait Kick starter stopper bait Shiit amt spring washer Shiit ieri pin lock washer 12254 5V Dii secl 5X24 Hex boil 6X16 Hex bait 6x12 Hex boit 6X12 Pius screw 6Xl2 Cotter pin {@@{ ®®5 S§®©i§>®0 Q6< y®®®®® g ,r ® 6'51 35/ @J 2?) Sell. Besides, there is equipped a switch to indicate neutroi state, which put tight on a indicator iarnp when the rotary swttch combined on the shift drum is in neutrui state The shift mechanism to actuate the above mentioned counter shaft 2 gear and the rnainshaii 3 gear 'is expiained as tollows. in Fig seii when the gear change pedal (i7) is pushed down the gear shitt spindie (101 is turned, and consequentiy the gear shift arm til) wril turn the drum {5) being pushed by the protrusion on the iett end of this gear shift drum. As there are shiti Fork guide pin t3i and guide pin roiier Mi which fitted on the gear shitt tork i2) in the groove on the center part of the shift dlumr rotation of drum acluuies gear shift Fork to move along the term at the groove irorrr side to side and the shitt gear is actuated. Here gear shift return spring (MI is fitted to return the change pedai to ariginai position and prepare next action and shiit drum stepper (6) is guide in tar ii. 108 c. Final drive mechanism The drive mechanism irorn crank to the rear wheel is called final drive mechanism. The main parts are as shown in ligure, primary reduction linlermediale ieduclionl. clutch, mission, iinal drive (propeller shall, final reduciionl wheel and iyre. \I. Clutch (5: Drive sprocket ® Transmission shaft © Primary chain @ Drive chain 1’77 Cranksi'iuh (:3) Final driven sprockei Fig. 3-12. 109 4. AUXILIARY PARTS A. Funnel type breather Breainer chamber cl lunnel Iype is Ibcaied in me rear upper side of me upper crankcase. Inside ine chamber breaiher body is suppbried by a spring and back pressure is guided along lhe direction as shown in me ligure separaiing oil to Outside of crankcase. Here a check Valve is lltled to avoid oulslde vapoul to be sucked, 0, Brealher body @r Breainer valve body (2) Breolher chamber (9, Breather valve ifr Breainer valve spring @ Breather suppcrl spring Q) Collel pin Breather valve (plain view] Fig. 4—1. B. Kick starter mechanism Kick spindle pawl iar Model C72. 77 males with the inside groove bi low gem by pawl spring 10 rolale low gear. When rial in kick. me head of pawl is pressed down by kick spindle meiai bush so Ihal low gear anains iree siaie. HO :1: KM storlei spindle (2] Low gear complete @ Kick spindle panel For Model 0572, 77 considering relation with the chassis, advance step kick system was applied. A piece ol gear was set inside the R crankcase cover to reverse direction ol rotation and can start engine transmitting rotational power to the kick spindle pawl. lF‘ig, 3—31 4i: R crankcase cover camp. ® chk starter gear (‘3, Kick anti ck stoiiei pinion r ; chk starter spring i; Clutch litter thread comp. Fig. A73. Crankcose cover C. Cam chain tensioner Inside Cum chain chamber located at center port ol cylinder cum chain (DK2l9794Ll is sel to transmit rotational motion oi crank to carn shatt, and corn chain tension is applied to make high speed motion of carn chain correctly and smoothly. Here the com chain tension works to suppress wavlng of chain by pressing com chain. In Fig. 44. 6mm bolt filled on the tensioner push bar be loosen, the roller will be pushed out by a spring to given adequate tension on the chain. According to slackness cl chain adiustnient can be done by this set screw. To make sure tightness of chain, it is favorable to adjust putting the crankshaft ot the bottom dead cenler. Ill l" 67 em spvocks! Q) R cum shah flywheel ® Cam chain 'ensionev <3 Cam chain iehsioner ® Cam chain tensions! spring ® Tensioner holder G) 5mm boii (5) Cam chain tensions! push bur @ Cum chain Iensloner arm @ Cam chain @ Cam chain guide miier @ Center crankshaft Fig. 4-5 117 5. CARBURETTOR The carburettor is a deVlCe lor supplying iuel and air into the engine. The performance of the carburettor will depend upon such iactors as most suitable mixlule proportion ol atomized iuel under all conditions ol speed and load ot the engine. Thereiore it must hos precision lor each pan and high resistonce for wear to assure the reliable periormance tor a long period, and so it is required inspection and maintenance. The reVised parts ot Model C72 lroni Model C71 are as follow. ll) Elimination of manifold. (21 Fitting type down dralt type. l3l Addition ol power let. Comparing Model CB72, 77 With Model C72, 77 Zrcarhurellcr system was adopted to increase horse power by eliminating branch to suction post. Concerning the power jet mentioned above. when MJA is set. the best condition is at 4000 rpm. and ul 8000 r.p m mixture becomes lean. but when MB is set as 8000 1p m. the best and at 4000 r,p,m. becomes lich. Thereiore V0 get lovoroole condition between 4000 rpm and 8000 r.p.m., MJA was selected to applythe power iet lrom 6000 rpm. to meel high rotation developing perr lormance at medium and high power. (i; Power iet (23 Blind plug ® Power on iet Fly. 5—]. Power jet system Construction (I) (2] (4! Air lrom the air cleaner possesthrough the suction port (1), lower side of the throttle valve 161, main bore (8) and time ihe cylinders, This air streom produces a partialvacuum in the area around the power nozzle 1241, by which luel in the lloot chamber (2] llows through power Jet luel pipe 1231, power Jet (22] to the power nozzle 1241. At this area. luel is mixed With air introduced through the power air Jet (2“. Then they are mixed With air llowing lroni the suction port. vaporized and drawn into the cylinder (Fig. 5—21. Mum system Air lrom the tiir cleaner posses through the suction port (1), lower side 01 the throttle valve (6] main bore (Bi and into the cylinders. This air stream produces 0 partial vacuum in the ureu around the needle Jet (41, by which luel in the lloat chamber (21 llows through the main Jet (10] into the needle Jet holder 131. Asthis area, luel is mixed With air (bleed air) introduced through the dir Jet (5) and the holes (9) proVided around the needle Jet holder 13). Then luel and air travel the gap between the needle Jet (41 ond the Jet needle (7), and discharge to the lower side ol the throttle valve. Then they ore mixed with air llowmg lroni the sucllon port. vaporized and drawn into the cylinder (Fig, 5-21. S_|ow speed luel system lpilot system1 Air lrom the suction port (1i passes through the outside 1121 ol the air screw in) which regulates the rote ofalr llow. Then air passes through the bleed holes (14) of the slow speed Jet 1131 to the slow speed Jet (13) where introduced into luel stream lrom the orilice (15] proVided With the bottom of the slow speed Jet (13J_ The rich mixture produced at this area discharges to the lower side ol the throttle valve ond is mixed with air llowmg lrom the suction port (1) and drawn into the cylinder. The minor mixture adJustment is made by means of the air screw (ill. Tum the air screw to the right to enrich the mixture and to the lelt to lean the mixture. The meior mixture adJustment is made by replacing the slow speed Jet 1131, Replace the Jet with one carrying bigger number to enrich the mixture and With one carrying smaller number to lean the mixture (Fig. 5721. Float chamber The carburettor must supply the correct mixtures which suit to the throttle opening and the engine running speed. in this connection. the fuel level must be held constant. The in system is a device to maintain this constant height. The operation ofme lloot system is given in the lollowmg. Fuel lroni the tank enters the lloat chamber 114 121 through the passage 1161. the valve seat 1171 and valve (18L As luel enters the lioat chamber. the float H9] will raise and move the valve {i8} upperword by means of the float arm (20). When the who touches the valve seat, flow of fuel will be restricted. As fuel level drops. the float lowers. opening the vglvg to allow fuel to enter the lioat chamber. Thus. any change in the fuel level causes a corres- ponding movement of the float. opening or closing the valve to maintain the luel level constant. There is a spring installed, against vibration, between the needle valve and its body at the location where the valve contracts the float mm 120). (Fig. 5—21 (5] Choke system The choke valve (2]) must be in a closed position with the choke lever moved up» wards, and in a open position with the choke lever moved downward, as shown in Fig. 5—2. \ X \\ @@ ® ® il5 (6] Adluslmem a] b} :1 Hrgh speed luel mlxlure adluslmenl Fuel mrxture between lull and halt open throttle posltlons l5 controlled by the marn let. To delermlne whether the marn jet ls correct. sllgmly close the choke valve wrth the englne runnlng at lull throttle I. If the englne speed Increases, the luel mlxture ls too lean. 2. It the englne speed decreases. the math yet ls correct or too blg. Replace the marn let as necessary ln such cases. Moderate speed luel mlxture adjustment Fuel mrxture between hall and one erghth throttle posltlons ls controlled by the adlustable yet needle and cut away ot throttle valve. 1. If the mulller ls black smoklng. the mlxture ls too rlch. tower the let needle to the next lower oosrtron. 2. It the englne mlstlres or hesllates when accelerated or drrven ol moderate speed, the mrxture ls too lean. Halse the jet needle to the next upper posrtron. The throttle valve cut away carrylng larger number brrng the mrxture leaner whlle one carrying smaller number brlng mlxture the rlcher. Slnce the change on the cut away attects the englne perlormance below one elghth throttle posltlon, the replacemem 0' Ihe Ihrollle valve should be done Carelully. tow speed luel mrxture adyustment Fuel mlxlure between one elgmh and rdle throttle poslllons ls controlled by the alr screw and throttle cut away. 1. Adjustment must be done by the alr screw mostly. Tum the arr screw "m‘ to enrlch the mlxture and out to lean the mlxture. 2 ll the correct odiuslrnenl connol be obtalned by the turnlng of arr screw, replace the throttle valve. (7) Fuel level adluslmenl As shown ln Flg. 5—3. luel level ls determlned by the helght H measured lmm the 110110!" of main bore. whlch varles among each dlllerenl englnes. However. slnce the luel level cannot be measured easlly. ll ls recommended to determrne by herght h, (f the float Floal adiustmenl cl Place the corburettor upside down 116 l l l k, c Q) Float (5) Fans 01 carbureum body a, Em of llaot valve ® Fuel slundcld level ® Float arm ® Mam bare bottom line (3, Em 0| "om Fig. 54. Measurement ul luel slandard level bl When the libel lS supporled with lingers lind Ihe position where the lloat arm lS about to much lhe top (f lhe llaol valve or the position having clearance ol 0 lmm. (0.04 in.l cl At this pasilion height diiierence between the end ol Ham and the carburelml body should equal to h and ll ll is mole m less man this umounl, adjust the height. raising or bending Ihe lloat arm carelully. h of Pw 22 26.5 mm (1.043 in] h 0! Pw 26 22.5 mm {0‘885 In] Note : At the lip ol the lloat valve there '5 lnsened a spring which creeps inside when pushed. As it prevenl to Show the actual position where the valve I: to be closed. ll lS necesslry m be cauiious to see the conlucl polnl between the float arm und llaol valve. 117 6. FRAME Construction of lrame body The lrame supporllng englne contacts wllh ground through the from and rear wheels and isthe skeleton uf whole chassls. Further II has tmoortant leature allectrng rts lorm and deslgn. The mam lunctton ol lrame is to malmaln chassls strength, supporttng engtne, rrder, and load on the carrler. and hasto endure shock due to roughness ol road through tyre and shock absoroer. On the other hand lt requlres ngldlty lrom Vlewpolms 0! control aolllty, and lurther requlres llghtwelght to chain better runnlng performance. The frame body ol Hondo 250-300 Model C72. 77 ls made of steel oi stress skln constructlon and adopted sucn crass sectlonal lorm as relregerator havlng round corner. The type of term has hlgh strength to bendlng moment and torslon. Tnerelore thus would be most lovomble form 01 Cone slrucllon lor motor cycle lrame havmg htgh rlgldlly from manulacturmg wewpomts. Especlally weldtng IS done oy new type of seam welder to attarn reltaole connecllnn and also untlorm products havlng oeauttlul outlook. On the other hand forthe lrame of Model CB72, 77. as mam strength memoers, hlgh carbon steel tuolngs were adopted to attaln llght welght and to lncrease ngldlty. <5) (I? Gasoline tank @ Gamer ® Spore seal @ Rem tender stay (5) Rear lender @ Shock absorber \ \ @ Rear lorlt ® ® Seal box Frame body Fig. 6-1. Frame body far Model C72, 77 118 (D Main plpe @ L, subJube holder @ From down lube fl (2 coil selling plole ® a, bellom plole ® Driver's lube '3 Tube holder 5;; R, sleo holder piece ® Englne hanger pluls ® R subrvube ® Mumer selling pipe (fig L. sub.mbe (53 Battery suppovl slay ® Center plpe @ Mam swllch brackel @ Sub-lube crossrmember ® Stealing need we @ L. bottom plate @ R sub-lube holder ® Fuel Iunk holder @ oemer pipe bushing RL rear cushion upper @ Key hole @ L. Slep holder pleoe brackets Fis- 6-2. Frame body for can, 77 H9 7. A. SUSPENSION Front wheel suspension The lronl fork of Model C72, 77 is made ol pressed steel and lor Model C572, 77 telescopic furk was adopted lo increase rigidily and lo cltdin heller running stability on rough road. A5 lhe cushion, lhe link syslem made it possible to reduce wheel base varialion and lo altain beller leeling m riding and beller controllaoilily. As shown in lhe figure ol shock absorber, it consists ol the main spring and double cylindrical oil damper. The spring lokes up compression load and lhe damper lakes Up recoiling lorce. For Model C72. 77‘ lelt and righl lronl cushions are combined by the suspension arm as one body, out lor Model CB72, 77 lnere is no suspension arm. ln lhe oil damper ol Model CB72, 77 lhere conloins while spindle oil 220 cc, and maximum stroke is 80 nm (3.'l496 inJ. 0, Front cushion bollom melal comp, ® Front damper collm ® Fronl msnion spring from damper inner pipe @ Front damper oil seal if Fronl damper pislon G) From damper rod @ From cushion reoound slopper spring Fig. 771. Crossrsecliori cf lronl cushion for Model 072, 77 Q) Fronl cushion e: Hinge (3, Suspension arm @ Supporllng hinge (5 Wheel oxis 120 (i Fork drain cock pocking Fork top bridge (13 Front tort oil seai retainer ® Front damper volve ® Front lork bolt @ Ring, 4o.5><3,u t 6) Fork pipe stopper ririg ® From lork washer ® Front tork pipe guide @ 3346i0. oil seal @ “0" ring. 9.4x2.4 @ Fork piston knock pin (5) From tork seal housing ® Front tork cover pocking (2i, From lork piston © Front lork upper cover ® Front cushion spring 52: Front lork bottom case (7? Front lork rib @ Fork bottom bridge @ Front lurk drain cock bolt Front tork upper cover ® From lork pipe comp. Fig. 7-3. cmsesection ol tront cushion of Model (3372. 77 Rear wheel suspension The rear wheel is pivot type construction equipped with also shock absorber. The principle ot construction of the shock absorber is alike that ol the lront wheel excepting such point as side pressure don‘t act on the sliding part and construction ol orilice on the absorber Is ditlerent. Special attention was paid on the suspension system on the pivot side as perlormance of shock absorber, monutocturing around the pivot and rigidity ol rear lork allect oh leeiihg ot riding greatly. As the rear lork of Model C372, 77, main strength members were made ol high carbon steel tubing to attain light weight and to raise rigidity. (D Hear cushion metal comp. @ Reor rebound sloppev Swing i? hear cushion spring @ Rear damper oii seol ; Reor damper innelrplpe LE, Hear damper rod. Fig. 7—4. CrOSSrSeCIlan 07 rear Cushion a! Model C72. 121 (I) Rear cushron rubber bushing ('1) Rear damper valve ® Reul damper oIl seal ’2) Rear Cushlon sprlng seal Rear damper case comp. qr, Rear dampel valve stopper Rear cushion Slopper Rear damper under lainl Q9 Rear damper plslon ” Rear damper nul Rear cush‘lan upper fem! ® Real cusman panam case Rear damper rad gmde Rear cushlon upper case 69 Rear damper plslon rm ® Rear (ushlon rebound sloppev Rear cushlon sprrng ® Rear cushlon spring udlusler sDrlng , Rear damper rod @ Rear damper Annabplpe Fig, 775. Crossesecvlon ol rear cushan ol Model C872, 77 ln me cylmder of lhe rear cushion Mere conlulns 60$ spindle all 37 cc lor Model C72, 77 and 47cc lor Model C572, 77. When vhe rear wheel gel shock rear cushlon Sprlng is compressed to absorb ll and reboundlng lorce is resrrmed by lhe oll damper 90 give adequare cushlom’ng. ll lhe amount of all conlalned in Me damper is no! suilable, eflecfive slroke ol cushlan becomes lo sham or lcaks oil or somerrmes become origin of shock sound The rear cushion ol Model CB72, 77 IS designed lo enable lhrea sleps ol udluslmenl according la raad sandman and runnlng slalev MEMO IZZ B. STEERING SYSTEM A. Steering handle Special attention was paid in designing the steering handle as this affects leeling ol riding and easy control. Especially for Model C72, it wos aimed to take riding posture easy to correspond quick manipulation of control, which would be determined by the lorm of the handle, saddle and step. Moreover on control parts, adjustment equipments are attached according to each riders' choice. These features could be said to symbolize Honda's kindness. , L. lrcnt winker lens a, R. steering handle lever Q) i. steering handle lever Throttle wire (3) Horn button (5?, Winker switch @ Head light switch ® R. grip rubber (5‘, i. grip rubber ® Throttle lever (Q R lront winker lens Fig. 8—I. Handle 07 Model C72, 77 The handle complete ol Model CB72, 77 is mode of one piece of steel tubing attached to the fork top bridge by means ol the handle pipe holder. The lork top bridge is fixed on the front cushion by 2 liont lork bolts. Each wire is exposed in assembly to make it easy to replace the handle. 123 (D. Speedolachomeler ass'y ® Stealing handle camp. 6: Handle pipe holder @ Sleermg damper knob Fig. H72. Hand‘e assembly of Model C372. 77 B. Steering Construction of steering 0' Mode‘ C72. 77V as shown in the Figure, is such having boll bearing and sleermg damper ol lriclion mare system to meet requirement Irom controlr labilily and srahimy at low and high speed running. Flg. 3—3. Cross Secuon of steermg head 0! Mode‘ C72. 77 124 For Model C572, 77, the steering stem which has cone lathe inside supported an the tram cushion by means of 8x32 hexagonal bolt is the rotational axis centering trame head pipe and is important part tor steering. On the steering stem. steering damper is attached and can be adjusted according to road condition. running state and loading condition. If the knob bl steering damper be turned to the right. steering damper spring nut is raised upward to clamp steering damper 'triction disc by means at steering damper plate A and B, consequently handle steering becomes heuvv On the contrary. it the knob be turned 10 the leit‘ steering damper spring not is lowered to make gap beiween plater A and B to become easy steering. (Fig 8-41 Steering damper knob comp Damper lock spring set bolt Steering damper lock spring Steering head stem nut Fatk top bridge Steering top thread Steering bottom cone race Steering heod dust seal Steering damper lrictibn disc Steering damper plate B Steering damper spring Cotter pin, 2.u><15 ., Steering top cone race Steel ball, 1/4” Steering mp ball race Steering head pipe Steering item Steering bottom ball race Steel ball. 1/4” Steering damper plate A Steering damper lock ml Steering damper spring nut i@©§>@®® @r‘: :E>@©©. s @fiiii ®®®6®i Fly. 3—: Cross section oi steering at Model c572. 77 125 9. BRAKE INSTALLATION As reliability and durability of brake installation are indispensable condition lor it, marine iacluring brake was paid special attention. Rear wheel braking is done by expanding the brake lining installed is the brake drum which is actuated by link motion to turn the brake Cam by pushing right loot. Here Special attention was paid to emit lrictioh heat generated to get better durability. For the front brake, by right hand operation wire transmits force to work and brake mechanism is alike with the rear installation. Q Brake cam Q Blake lining ® Elmke drum Fig. 9—]. (T, Brake shoe width 30 (3 Brake shoe ahker pin 6) Brake drum inner dia.. @ Brake shoe out die (5: Bmke cam 126 10. A. CONSTRUCTION G‘ WHEEL Front wheel Front wheel body made of aluminum casting of whole width hub containing bollbeun’ngs and brake drum inside is fitted with brake panel and speedometer Uni. by wheel axis and nuts. To assemble the lront wheel to the chassisil (m the lower end of lront lork slide pipe by the axle fitting. Reaction occured during braking can be caught by the left side bearing through the stopper of the brake panel. i Fig. 10—]. Cvoss Section at ham hub 123 Rear wheel The rear wheel ol Model C72, 77 is consisted of wheel bearing, rear wheel hub ol aluminium equipped With the brake drum, the linal drive llange serving chain case partially and broke panel. On the left side. the brake panel is equipped through the distance collar, and between the wheel hub and the linal drive flange there is litted rear wheel damper. On the right side at the wheel hub containing ball bearing, the chain case is equipped through the final drive llange fitted with the rear wheel damper and the linal driven sprocket. and is tighten on the rear axle passing through the left side oi the rear fork through the distance collar on the left side. The rear wheel damper absorbs not only abrupts variation of rotation during braking and driving lorce ol the rear wheel hub. hut also is uselul to protect transmission mechanism. The rear wheel ol Model C872, 77 is consisted of hall bearing l6304l, the rear wheel hub ol aluminium casting equipped With the broke drum and the brake panel. On the lelt side there equipped the rear brake panel ol tWin can type through the panel side collar and on the right side of the wheel hub. and the linal driven sprocket are lixed by the sprocket setting bolt, and fixed on the rear lork by the rear axle through the rear side collar. Flg. 1&2. To draw out the rear wheel imm the frame lModel CB72, 771 129 (D Real wheel damper ® Fmal drive vI-nge @ Fim‘ Gwen spmckn Fig‘ 10—3. Cross-section cl rem mm 130 11. AUXILIARY EQUIPMENT A. Air cleaner The air cleaner element made of lilter paper is stored at the center part of the body utlilzlnga point of excellence that the home is made of s‘lccl sheet. II is aimed to get petter lilter eiiect by expanding snrtace area and also to prevent rain water to enter. For Model can, 77, as 2 carpurettcrs are equipped, alr cleaners are iixed (11 both sides each. (C An cleaner connecllng tube (gt Air cleaner element Flg. ll—L Air cleaner oi Model (:72, 77 65 An cleaner connecting tube (:2; Air cleaner element 6, R. an cleaner support stay @ Teal box complete I , (3 L. air cleaner support slay Fig. llez. Air cleaner for 6572, 77 131 I. Mufller Musliflfloi exhaust mumer. Exhaust pipe conducts exhaust gas nom cylinder head 10 mumer. Culvalule of this pipe alfecls holse ppwer developed exhaust gas conducted mrougn exhaust pipe is damper inside 0! mulller by checking passage and lunher discipme sound of me diuuser pipe to get silencing eflecl. (3 Diffuse! pipe Fig. 11—3. Crasssecliun of Mulfler a: Model 072, 77 (1‘, Muffler (2 Difluser pipe Flg. 117‘. Crossrseclion 07 Muffler of Modal C572, 77 MEMO 132 ELECTRIC EQUIPMENT 1. Ignition system (Ignition coil, Magneto, Contact breaker, Spark plug} .N Electric power generator (Rotor type A.C. Generator, D.C. Dynamo) 3. Rectifier (Selenium rectifier) 4 Battery 5-“ Loading (Illumination light, WinKer, Horn, Starter) Electric system is important part for the motorcycle alike nervous system for humankind. Even a partial damage at engine ignition, light at night or horn function Will allect quite often its smooth running. We adhere on JIS standard lrom viewpoint of manufacturing and tralfic transportation motcrcycle low and security standard for laws and standards. 133 1. 2. 3 CONTENTS SYSTEM A. Ignition Circuit .............................................. 8. Contact Breaker ............................................ C. Condenser .. D. Spark Plug .................................................. E. Plug Construction ............................................ Wiring Diagram .............................................. CHARGING SYSTEM A. A.C. Generator ............................................ Celenium Rectifier .. C. Battery .................................................... D. Ceil Starter E. Maintenance of Starving Motor ................................ F. Starter Magnetic Switcn ...................................... SAFE GUARD PARTS ................................................ 135 137 140 143 144 145 150 i7i 1. SYSTEM OF ELECTRIC EQUIPMENT As ignition system. ignition coil and contact breaker are used. For electric generator, Hotorrlype A.C. Generator is used, charging battery througn selenium rectilier and dis charging according to several leading. ® @ Head iigrit @ laeiey (2) Hum Selenium rectitier @ Main SWiICh Battery (9 Wire harness @ Stop switcn (5) ignition coil ® Tail i: Sign light ® Rumnype A.C. generator Fig. l-l. Ignlllon clrcult Ignition system In gasoline engine, at the lavorabie time of the uppermost position of compression stroke mixture gas should be hunted and exploded by any means ol ignition. For both Model C and Model CB, high tension oattery ignition system is adopted (Fig. 1-21. (T, Ignition coil (2) condense! ® Contact breaker ® Spark plug Fig. 172. lgnition system 137 2. Ignition coil Ignition coil is the some construction with that for Model C72. For Model C572, 77~I type. there equipped with one coil each corresponding to 2 cylinders right and left, as the crunkshotl angle is 180 degree. But lor Model CB72, 77—11 type. alike Model C72. one coil ol simultaneous ignition system is equipped as the crankshaft angle is 360 degree (Fig. 1—31. M_..\ iii [12. call tor i type ® :2 caii ior iieiype Flg. I»3. Ignition coil 9ons7truction of ignition coil Ignition coil is shown Ill Fig. 1—4 where tine enamel wire of 0.08 nm dia. ls wound over the iron core about Loco—2.000 rounds as the secondary coil on which further enamel wire ol 0.6mm dia. Is wound over it about 200— 300 round as the primary coil. And stored in the cylindrical case alter insulating process ond drawing (ml the terminals (Fig 1—41. T, Battery ® Insulation (3) ignition coil Qt) Secondary ride (5) Primary side 6;) Primary current ® Conlacl breaker Point cam ' ' Condenser v92 7,, a: m (iii Spark plug Fig. 14. Cross-section ol ignition coil 138 anary terminal Secondary termino‘ 5; in: lln’ an i Iron core 6) primary coii (53 Secondary coil Fig. 1—: Function diagram of ignition cail cl Modal C572. 77 B. Function of ignition coil The principie ol ignition coii is similar to that ol induction coii. As shown in Fig. 1—5, rotating cam axle and crank with conslunl periodical relation. there generates high voltage on the secondary coil as loilows. a When the point ol the coniucl breaker is closed primary current liows in the direction as shown by arrow and generates magnetic flux inside the iron core. When the point is opened by the cam. the magnetic flux which is generating by primary current is going to disappear suddenly. Due to large variation ol magnetic llux and large number of winding. there generates high voltage in the secondary coil. Here generated nigh voltage Will charge on distributed static electric volume of the secondary coil itsell. then as it voltage increase, lurther stan charging on volume ml nigh tension cord ond plug continuing increase of voltage. When voltage increases up to ample amount. spark Will occur at the plug gap. As soon as spork started sparking voltage drops down instantaneously. Accordingly electric loud charged on the distributed sioiic electric volume Will be discharged totally tvoiumetric sparki. And continues discharge at energy contained in the Wire by disappearing magnetic flux iinduction sparki. Magnetic llux approaches down to zero instantly where voitoge no more moinla'in spork voltage and discharging spark disappears. Still energy in Wire due to remaining minute magnetic llux Will generate damping Vibrotion inside secondary and primary coil. and disappear acting as resistance loss on the circuit. Then returning cum angle to original state to actuate the lunction as stated (0] to lollow the same process repeatedly (Fig. 1—5~l—7I. 139 Ll} Contact breaker Po‘tm cam Condenser Battery Insulation Ignit‘ron cait Fvaary eon Secondary can Spark plug @@@@@@@® cod 0‘ Mode‘ C72, 77, CB72. 77 ® Spark gap ® Contact number at contact breaker per minute < plug gap dtogram of mechanism to operate contacting and breaking )r magneto ignrtion corl securely. It 'rs stored type magneto and fitted on the fixed stand for tor separated flywheel type and battery r’gmtion unit. The contact breaker rs consrsted oi the a contact perm and fixed point), |ermtnc| ot tte >regnated with cloth or pressed thin steet attached ‘fher end of each part movabte contact pornt rs ty. red to move very Irghtly, so it ‘rs desrgned to be )ke rnenia smalt. it is necessary to put a (one tHe in short of the point. On the other hand rgth to avord disorder'rng of flung timing due to I40 Generally conlacl pcinl pressure lS designated belween 700 and 900 gr. and lo prevenl wear ol the cam lollower grease should be applied on all fell. Required characlenslrcs lor painl are as lollow. ll High unlirweallng properly. 21 High heal conduclivily. 31 High mellmg polnl. 41 High unliroxydmion. 51 Have a modelate hardness. 4T, Fixing hole cl conlucl hrelker ® Dil lell ® Breaker arm @ Poinl (a) Terminal © Spring (7“, Poinl Fixing screw Ease cl contact palm Flg. 1—8. Fig. 179. Conlact breaker assembly - ® a, 2 perms var Model cm. 7771 type @ 1 point lcr Model C72. 77, ror C872, 7741 lype °° ° 2 Fig. 1-10. Conlact breaker ' 0' Model C572. ‘00 _ 00‘ 7771 Iype 1‘" Generally for automotive use, 4— 5mm (0.157~0.196 in.) tungsten lS applied. Sparking is generated by magneto cam contacting and breaking oi timing of crankshalt and cam shalt by the contact breaker. Fig. Hi. Contact breaker oi Model C72, 77, and Model 0372, 7741 type One cam is profiled at the end of the point shaft connected With the spark odvonce inside of the cylinder head tor Model CB72. 77—1 type, and 2 sets ol contact breakers are set relatively at 90 degree on the base. and designed to operate at correct timing at L. and R cylinders. 2 coils, 2 points, i mount cam lor Model C872, 77—1 type. One mount com \(D Fig. 1—12. Point shalt cani profile (Model cm, 77—1 typel For Model C72, 77 and Model C572, 77, 2 cams are proiiled on the point shalt and 1 contact breaker is fixed on the base. Here simultaneous ignition system is adopted as explained in the borogroph about the ignition coil. Model CB72, 77—11 type: i coil, 1 point, 2 cams and simultaneous spark. 142 @ ea. Flg. 1-13. :mm cam prcfil (Model CB72, 77 and Made] C572, 7741 yypel Nate : SurioCe of palm becomes rough with working time elapse Especially there occurs exvmmd'lnary weor rt ottoched oil or grease or the pOlnI surllce. Funher ll attached orl or gyeus: an the point surtace be lett done tor a lung nme. it solrditres and terms insulating surtoce to ettect ignition be impassrble. So special precaution is needed to prevent attachlng oil. If the surtace or point becomes rough or dirty. use o tine tile or sandpaper to polish and adlust, and it case is more worser. take out the contact breaker base and the breaker base and the breaker arm, polish both contact surtaces with oil stone, In Ihls case special attentlcn is needed to avord one side wear. This one Side wearing attects very bad rntluence for a new part cr repalred part. Theretore centering and parallel adlustment oi both contact point IS essential requirement. Also rt there is tound too much play wrthin axle hole oi the breaker arm it is needed to replace with new one. 01 the other hand, termlnals oi contact breaker and insulating parts 01 wire have to maintain ample insulating standard. so thol SpeClal precaution is required to keep clean avoiding vapour. oil, dirt to be attached. In case of adiustmenl oi the surtoce at point wlpe its surtace wlth clean cloth stoined with trichrene to avoid grease. oil or dirt to be attached. C. Condenser Function of condenser is to aVOld harmtul spark between points. and if taken its volume value too large spark pertormance becomes worse. Theretore generally it is selected adequate value between 0.1 and 0.35 mrcrotarad. On the other hand it is required such leature lo reSlst hlgh voltage as high voltage or 143 several hundred volt acts on the condenser at the point opening instance. 50 it is prescribed in the JlS standard that it should reSist more than one minute under such condition as A.C. 700V (50 or 60 (2/5} maintaining insulation of more than SMQ alter heating 30 minutes at 80°C (Fig. 1-14. l—lSl. Fig. 1-14. Condenser tModel can, 777i iypei Fig. 1-15. Condenser (Model C72. 77 and Model C372, 7771‘ Maui Simple test for condenser is done like the lollowing. After checking insulating value by mega, disconnect both poles ol condenser lrom mega while mega is running. then short both poles by wire. At this instance, if spark occurs large enough. it is decided the volume value is good standard. By me ol the service tester it can be tested preCisely volume value and insulating perlormance. D. Spark plug Spark plug plays the most imponant part Within ignition system ol engine, and it takes charge of staning engine, receiving high voltage generated by ignition coil or magneto 144 E. to make combustion ol mixture gas by high voltage spark occured spark gap within plug in the combustion chamber, a l Conditions needed to embody lor spark plug There are live subiecls (0 be solved to lullll lls luncllml pelleclly. which will he explained as lollows. (A) (El (Cl (DJ {E} Current Electric current llows through the shortest way. and always tries to spark out ol spark gap. At monuol temperature electric insulating character ol insulation Is high. but at high temperature this character decreases. Therelore it is needed high insulation material which is hard to decrease its character even at high temperature. Explosion pressure inside the cylinder, 357 45 atmospheric pressure due to explosion olwoys seeks path to escape. ll air tightness of plug is inadequate, combustion gas ol high temperature will penetrate inside it to loose its lunction due to overhauling. Combustion head Temperature ol combustion or mixture gas will reach up to 2000“C. ll is needed to discipate this heat sooner to develop engine perlormonce preventing over heating ol plug. sparking in advance or burning electrode. Carbon in case ol incomplete combustion ll get dirty on the insulming port, engine Will lail its smooth running due to high voltage looks partially ond poor sparking. Lead compound Arelhyl lead is contained in gasoline to control explosion. and lead oxidized compound is mode due to combustion. li it IS deposited on the plug. this coma pound becomes a medium having conductivity ol high temperature and high voltage current will escape as explained belore. Construction 0| plug Here is shown the plug used generally lor automobile (Fig. l—lél. u] Electrode As material of electrode it IS required to be hard to wear. low sparking voltage. high heat conductivity. high resistant to oxidation, high conductivity and easy to manulacture, At present Nickel alley or heat reSlslant alloy ls used lFig. 1-17) 145 Adhesive Wire packing Plate packing Central pole Screw wrdltr Lularol pole Terminal nut Insulator lwittr carrugetroni @@@@®®@@H Powder filled :iotr Spanner pun lhexagonull ~‘—® gig Main bodv @ Gasket lh® lg Spark gap Fig. 1716, Plug conslwct'ion (I) iron wire (2) Copper wire ‘13) Special nickel alley rig, H7, Construtlion oi electrode bt Insuloior As insulator, specrai higti alumina substance is used mainly. This material hasa very excellent churccler comparing wrttr that of tamed loreign producl. This superb character can be attributed la high contenl of OlUmmU and e perlect material refinery process and can maintain mgr periormunce due lo burning process in high temperature turrrrei oven lF'ig. Hal. x1) Special high alumina substance lg) Corrugetion no prevenl blush overt Fig. 145. irsuiemr H6 cl Concerning plug insulator (Insulator at special high alumina substance) Characterts’lc of insulator and spark plug ' " .c- = u 3 l 3 23 9- c e .e we will -- a -> GE 01': “2 5 a: l a: s. :0 t; l"-- V em .9 >2 g “c “0 Cam asltions E; lnsulatronresrstance 95 E? of, fijo ‘A“"U 9 Ear M 3‘3 ‘98. 1'1”: 0‘5 “‘5 °° ‘” “3 .2x 9: 4:3 Eu) :3 a a (a) tag .- =3 :_ e a E a: a. g o o a, n o o o r» e e = < u u u I < ( l 7 W D ~ l ~ gtcc i200“: 300°C ADO“C 500°Ckgt‘cmilzlomgiyc Cot/cm 75ml PbBV; PbO (lb/'tnzl l9o.2 7i 351 co m 800 an ll,300 75x 9'0““ 6 ‘ “mm l0“ oozvtimes 0'07 ‘32 Main benefits at this insulator are as lollowmg (Al A5 insulating character is excellent, it rs not trouble of misfire due to decreasing al insulating character at high speed loading candrttori Wllh preventing eflect at nush over by the head corrugation. (Bl Due to high hem conductivity, heat conducted to plug can be discipated quickly preventing over heat. (Ct Due lo high resisting character to heat shock, thEre is no trouble oi damage on the insulator by sudden raise and drop of heat no gas leakage due to strong construction. To loin the central electrode with insulator, and tnsulotot wilh main metal body, special powder ‘ts used This way ol filling pewdet is prevctled method in the aircrult plug manufacturing and comparing usual cement adhesran. Air tightness is pertect lar long range use accordingly central electrode can disctpu'e heat evenly and distribute heat evenly. Amount of wear al electrode is indistrtct. Larger size at diameter at electrode is adopted to ease heat discipation and to get least wear and special allay having heat resistant character was selected corresponding to such circumstances at high campression and high rotation, Very strict tesllng is done betore using as even a mlnute crack in the material might be the cause at extraordinary wearr a] Heat value at plug al Favorable condition tor plug lunctran Ignillorl part at plug rs up to be dirty by carbon generated by cambustron gas H7 bl cl during engine revolution or by oil penetrated into the combustion chamber. This deposit is electric conductible itself, and makes short circuit ol high voltage electriCity. Accordingly weaken spark to decrease engine power misfiring and in worst case will stop engine revolution. To prevent such phenomenon surlace of insulator should be healed enough to cut ofl carbon deposited, and this is called “sell cleaning temperature " (about 450°C~600"C according to engine statel. On the other hand, it burned sparking part ol plug at higher temperature, spar- ing part will become over heated point which inVites harmful knocking to burn mixture gas before hand than sparking the plug, which allect decreasing of engine power. Therelore it is requested that temperature of whole body of spark plug should be maintained lesg than that of premature sparking (less than 800°C according to engine state], As a result it can be said “sparking part of plug is no good if too cooled also if too hot". Escaping of heat Heat received from combustion gas escapes as shown in the figure and sparking port maintains a certain temperature balancing heal quantity escaping and receiving. Necessity ol dilferenl types of plug having each dillerent heat value.—Dilference of heat quantity received by each plug. Heal quantity of plug received from engine depend (11 kinds of engine lair cooled or water Fig. 1-19. Woy oi escaping cooled. 2 cycle or 4 cyclel, design lcompression ratio, h eul shape of combustion chamber, plug position] and running state (speed, loading, diflerent fuel, flat ground or climbing slopel grcatiy. Therelore it Is necessary to furnish difierent types of plug to function satisfactorily under each dillerent operating condition. This rate of escaping of heat is called "heal value ol plug", and it is delermmed by its construction, form, dimension and material. It is called "cold type " (for high temperature usel which discipales heat easily and is hard to be over heated. and on the contrary such types as hard to discipale hem and easy to be heated is called “ hot type " (low tem~ perature usel. In Fig. 1—20, diflerence between types functionally are shown. MB k L ‘J ® low \empemure use ‘ ‘ (hm lyPel ”j“ ® Medlum \empemure use $1 (medium Iypel \ g Q) ngn Iempermwu use ‘ ‘\\ , (cold Iypel Fig. 17m Dmerenl plug lor heal common 0 -_V 9% may an Smnalh running B (3) lgnmon loo eally A Low power Fig. 1-21‘ Hm type plug «on law 1empmmra use} 149 WIRING DIAGRAM oF HONDA 250 8- 300 (MODEL c12,cm Heal 4”; mm ‘? @ugw @7111“: @wgzm @«fiw @ @rrflink {@riz'jfitflmm (@WUJI/iffllds L (E) Viz/Mm find @E»~zzy/zz 6m and flea: wire coma! wzt/L Mu: tuba fik-flfiwe "vfllurk W2 cave/at MM red MA: Wf/zkcr 3w & 5mm 5/1 ttm fi’ani Maker : ‘ LW my - , \ 51¢,»qu 5A um 2);; Hum 5a 1 14*; & [Jim/Mr fl»: jlartZ/zy a Mu tw 03/7“ Celnu'm Win/(er Relay Rfi’eurM/z/er flectzfm . (MP/W @— W w a >—@_ P F I 1’ fit I?) E ~¥ P m <3» S Start” ‘2 3 a: Eé‘atb’zgrf n ’7 Fuse 2 (l t V. k H ‘: 15A ‘“ 54 y $ m 5 y WIN \ ”m 7 \ 5221mm fat/fly/ p‘ MflA/L 6W 4W {wiffm 510M“! Edi/l lamp 7 4}! _ A/Cu trad 5w. Cunning/V law [m taci firm/m (g)-~omyg (R) 7&4 5mm mama/M (Fm) azmmmm (R,W)~/PedandW/zitc 1. Rear Wafer 1W W A c. [734‘an @7775ch m comm/m 7511mm film We rave/n1 m wme m; @wtmm ®~ , thlih’ air/941“» ~61“! l9l Wiring Diagram of glgrler mummy; : w 4mm wt‘er quhimq SW HONDA 250 300 (C372, C377) sr Yo}? fm ~ ner'or [mu MAL Mom {mum : / mu an: w 1w 5an 5w f am ‘ Huh vensnn Dmmer 3w / s-arm nnlm , up“ Bum 1%me ; man tensmncord A r (mm mm flute # mm :uble {mu m 7 \gmer mu nzhc sw mm sw 52w AC amumn \ '(rCflnrkr shah) 7 / El QR E v r n x v u? mu: r30 :1 ”NR ' (D m s ‘3 gin 7 ' w: R 81 G W Sun a 'm hgm gs/sw) Mute Wu: harness M mug: 12 Volts mm Green ,raackuhd "YeHuw a Rm , Lxghfi Green ~ Red ”White 1 Mn flunk a WM: 2. A. CHARGING SYSTEM Rotor-type A.C. Generator The principle ol generation 01 electricity by Rolarrtype AC. Generator is same as that of the llywheel magnets. Magnetic llux in the iron core ol coil turn its direction as much times as number of magnetic oole lor each a turn at the magnetic iron. For each a turn 0! the magnetic iron, as magnetic llux in the iron core changes With _m_agnetic pole number 2 cycles (3 cycles per one turn lor 6 poles generotorl. so there generates A.C. voltage in the generating coil due to this variation of magnetic flux. The more magnetic lorce ol magnetic iron. and the earlier rate of change of magnetic flux inthe core (rhe more quick the rotation oi magnetic iron, and the more number ol magnetic poles] ond also the more number cf winding ol coil. the large A.C. voltage is generated (Fig. 271, 2—3), All these conditions couldn‘t be satisfied lrom viewpoint ol manulacturing, and among magnetic lorce ol magnetic iron, numoer ol magnetic poles and number of winding ol coil there is such inter relation as to increase one sacrilicing other, Due to delects ol HomHype A.C. Generator (Flywheel, generating coil of Genermor), which works with wrong voltage variation and not equipped with a voltage regulator. there occur too much raise or drop of voltage il take the loading at random not using regular loading. But recently these delects have been overcome by magnets manulacturers' ellort, On the other hand lor magnetic weakening ol magnetic iron preventive measures have been token in the course of design. (Fig. 2—21 A point of excellence ol Rotorrlype A.C. Generator due to it simple and strong construe tion is almost no trouble and lack ot wear pans. Special leature ol using RomHype A.C. Generator combined with ignition coil is to make it possible emergency starting Fig. 2-1. Rater-type A.C. Generator 152 which is impossible to be tollowed by Rolorrlype A.c. Generator. Frequently there occurs pertect discharging carelessly lrorn capacity battery mounted on motor cycle. due to its small capacity. For the battery ignition system, it is impossible to spark unless replacing battery or recharging. but tor the Rolorrlype A.c. Generator system it is still possible to spark by kicking even alter pertect discharging of battery due to its teature ot steep and high induction voltage oi Holorrtype A.C. Generator under light load where generated voltag be conducted ta ignition coil in D.C. or M). as it is through selenium rectilier. Therelore it enables emergency starting by sWitching oi adequate circuit connection. a) Coil A: Generator (2“; Fixed core liron core and coill ® Yellow (usual usel ® Rotor (magnetic ironl (23 White (day and night] © Cmrkshah (a) Brown {common usel no. 272. Construction at RotoHype mg. 2—3. circuit diagram at AC. Generotor RotoHype A.C. Generotor A B 20 ”7 q 5 75 0 mm 21700 300E 45170 .5000 A000 70.75 Map 41700 7017017 (if Battery vollag: Ec A Volt ® Charging current 23 a: Anp Fiu- 2-4 (a)- Characteristics of Rotorrlype A.C. Generator (daytime) 153 10 ID l l @ m s 4 a a 2 i I 0L i 7 . I'li7'7 PEN JD!” 4000 511M [id/M 700a .7001: 409” 10400 ® Battery voltage Ea A: Veil ® Charging current zE B: Amp Flg. 2-4 (bL Characteristics ol Rolorrlype AC. Generator (during night) I. Selenium rect The selenium rectilier is used lor rectilying the D.C. current lrom the A.C. current, always combined With Rotorrlype A.C. Generator or A.C. generating coil. There are several kinds of construction, material and lorm lor this rectilier, out the principle is some utilizing its special character ol easy llow current to one direction and closing to other, Types ol rectilier generally used are selenium recliller‘ copper oxide rectilier. and germanium rectilier. Rectilying unit to rectily by the selenium rectilier is shown is Flg. 2—5 lol, and is composited by rectilying plates combined with end plates 69 5 (Al Rectirying plate Q) lnsulaling membrane ® Electric pole i? Selenium @ Positive direction B (5) Bare plate (nickel plated steel or aluminum] (Bl A sign at rectilier or rectilying plate (3) Direction ol current ’® Fig. 2-5 (a). 154 and spacers of required number in series or parallel and lurther according to rectilying system it is set in combrllke arrangement on dillerent rectilylng circuit style. Rectllylng plate is shown in Fig. lAl, where on the base steel sheet or aluminium plate ol nickel plated circular or rectangular lorm. rellned selenium mixed with an adequate amount ol impurity ls spattered in vacuum and lurther ready {usable alloy of Cd, Bl or Sn IS pured on its surlace to make electric pole alter perlect heat treatment to make it active metal selenium. Then it becomes possible to get such phenomenon as current is easy to llow to positive direction and almost shut to llow to another direction ll put current to the reverse dlreCV tion to that shown by arrow. This is called rectilylng action of selenium rectllylng plate. This characteristics caused by unsymmetrlc conductivity due to the layer of barrier on the contacting surlace between pole and metal selenium oi semirconduCHVlly. As moisture is very harmlul ellect m the selenium rectilylng plate. unllrmoisture processing is done by moisture resistant point to prevent corrosion. The selenium rectllylng unit which is common lor Model C72, 77 and Model C572, 77 is connecting in bridge and number ol selenium rectilylng plate becomes much and the ignition coil works lor both cycles ol positive and negative loading. Durability ol the selenium rectilier depends on temperature largely, and it is prohibited to raise more than 30°C. So is requested not to llow over current lor a long time. (D All wave rectilier ® Generallng coll A.C. volluge g) D.C. @ Enltery © Loading Fla. 2-5 (b). 0n the other hand. there is sarcailed resisting reverse voltage which more voltage l5 put to reverse direction there occurs puncture (Here punctured part turns to be insulating substance at once and this damage seilrresmres its lunction reducing ellectlve rectilying area. The more number oi puncture. the more rectilying elllciency will be decreased to 155 be overheated). Therelore lt is necessary to ralse total reslstlng reverse voltage by pulling required number ol plates in serles corresponding to A.c. voltage generated by the generator coil in Flg. 2—5 (b), put A.C. voltage between termlnals P0. of lhe generatlng coil as A! 'IB) : lC)= the reverse voltage per one rectltying plate ls smallest. Generally speaking is selenlum :2 :1, lt ts evldent (Cl ls most suitable lor high A.C. voltage rectllier as rectllying system lor use ol automotive A.C. generallng coil lCl>lBl>lAl is the order to select corresponding to voltage. Selenium rectltier ass'y Red termlnal Brown terminal Volt Yellow terminal untrue Fig. 2—5 tel. Remarks: SpeClal precoullon is necessary ln using selenlum rectilier not to run englne under such condition as no loadlng state (for instance unloodlng stole ol battery during daytime or taking out stole yellow ollusel. as high voltage generated by generatlng coil under no load or llght load condltlon acts to the reverse dlrection. Thls leads to puncture trouble and Wlll damage the selenlum rectlller ll con- tinued is long tlme. On the other hand, there occurs ageing chonge in the selenium rectlller tor a long term use increasmg lnternal reslstance in the rectlller plate to decrease output voltage and to lncrease temperature. The largest cause at ageing chonge is temperature raise and at more thon 70°C in the rectlller this chonge occurs rapidly, theretore lt is required to select cool position to equip it. There is such tendency as to increase current to reverse direction it selenium rectitler has not been used tor a long tlme. a such case, belure uslng tul'se valtage slowly durlng one hour trom lower voteoe (about hall at standard] to restore lts tunctlon. C. Battery All the battery lor automotive use are lead storage battery and lls constructlon Is as shown in the ligure that ls anode plate group and cathode plate group (one plate more than anode group] are put together ln turn lnserting separator oetween anode and cathode plates. and these combined plates are stored in the cell lebonlte or stlrol model dipped with electrolysis solution. One unit as shown in Ihe ligure is called on unit cell and 155 , generates about 2.1 Volt lin case ol perlect charge, this wtll be up to 2.5 Volt during charging). For Model C72, 77, 6V IS used and {or Model C872, 77, IZV is used, connecting each cell of each 3 piece or 6 piece by connecl'lng rod in series. : lermlriul pale . dilute sulfur'ic acid - anode plate v ierrnrnal cell . sepuiulov i cathode plale 1-me an ad Fig. zed. Storage ballevy The pole plate is made ol lead antlmony iaiiiee painted w‘ith powder al lead ox'ide tn paste state uiid dvicdu For anod'ic plate, hard lead oxide in dark brown color lS filled up and lar cathode plale gray porous sponge like lead ls Filled. There contains expanding substance to prevent contracting solidification while ln use as tor separator ihin cypress sheet lreccntly rubber sheei With fine holes or sylhelic plates are usedl is used, and glass mat is inseried between unodlc plate and separator is prevenl OXIdUVlon of separator and dropplrlg substance ol anodic action There occurs discharge when connected load between both ierminals of battery, and gradually subslunce of both pole plate Changes to lead sulphate, accordingly, specific gravity of dilute sulphuric acid wrll decrease to drop terminal Volluge, This rate of decrease of specific gravily A p'QpOrllOnal l0 amount ol discharge approxlmclely as shown in Fig la). So it will be determined amount al discharge or remaining amount by checking varialion cl specific gravity it known the initial specific gravity lsg. at complete charge i 260 and 59 or complain discharge l,i0l. Specific gravity ol dilute sulphuric cCid varies wilh change or iemperdiure. ll also depend on ihe kind at ballery but generally about 1,260 lS selected With converting standard temperature 20°C. ll out current on the discharged baiiery in the direction reversal ta discharging, lead sulphate generated on both plates reslore their original state ‘ie. become lead oxide and sponge lend again, and specific gravity at dtlute sulphuric acid increase gradually and increase terminal voltage as charging progress, GD E? m (D tat Discharge characteristics it is» (3 under constant current ii an i iu @ 'j Voltage saecitic gravity Discharge l'im'it voltage t-tours at discharging current End at discharging " Complete charge Total discharge Amount ot charge Fig. 2—7l Battery at Volume and rate at discharge irate ot chargingt Volume of battery is defined as amount at volume dtschargeable dawn to discharge end voltage at terminals regulated by its trom complete charged battery discharging under constant curient (mean value 1.575V per each unit cellt. To express its value ”Ampere hour (Ahi idischargrng current times discharging hours! is used Volume at battery depends on temperature at discharging current and specific gravity. As conditlans of volumes test reQUIated by JlS tor use of battery (or motor cycle, specific gravity ot electrolysis solution should be 1260:0005 (converted ta 20°C), current 10 hours rate, and temperature at solution 25:2°C Concerning rate at discharge, glven here the battery completely charged, discharge down to the end discharge voltage wtth X ampere wrthin T hours, volume of this battery is expressed by XT umpeteshouvs (Ah), and X ampere is called the current at rate of discharge of T hours. Theretare battery at to hours rate volume it Ah means such CapcICitV as to discharge to hours down to the end discharge volt and current at 10 hours rate of discharge is ilA. Similarly tar charging current it is expressed to hours rate at charging, To express amount at charging or discharging current duration of time in hours down to the end discharging volt is used, b] initial chmglrig Battery can be stored atter assembly tor a lairy long time, it not electrolysis solution l55 be poured in and seai tightly a pouring orilice. Therelore when battery not charged yet isto be used initial charging l5 necessary. This is done alter pouring electrolysis solution charging with regular initial charging current for about 70 hrs. continuously to (main both pole plates a perlect charging state for the lirst time. It is iequired the initial charging should be done perlectly, otherwise this battery will not display its volume 100% lor luture use and its life be shorten seriously. Precaution necessary before starting lor use: Inspection should be done belore use ol battery finished initial charging as lollow: (l) Inspect ii there is something unusual or not, as damage, happens sometimes during transportation Especially due to damage on the case there happens leakage ol solution. 12] Peep inside through pouring port after taking cop, or check the level 01 solution to be at regular height. If its level is lower, check damage ii any on the case. If no damage, supplement dilute sulphuric acid ol same specific gravity with other cell. t3l ll‘ time elapsed more thon two weeks after the initial charging, it is necessary to supplement charge to supply amount ol sell discharged electricity while let alone. During this supplement charging, it is desirable to check level at solution to odiust regular height and further measure and keep record of voltage, specilic gravity and temperature for each celi for future relerence. Fig. 2—8. Supplement charging at Battery Precautions while in ure : (1] Inspect battery periodically, once a week for automotive use. At least twice 'a month or alter each LOGO—2.000 km (620~1860 milel running. 159 (2] (31 Special attention should be paid on lhe level ol solution and it short supply distilled water or drinking water (no contenl ol metal as lerrous]. ll lhe case ol ballery is lransparent lhere is shown level of solulion. bul generally the heighl of solution should be adjusted about 13mm 10.51 in.) over the separalor. ll the pale plate be exposed in lhe air due to drop ol level, there occurs oxidalion on the plate making white sulphuric lead which decrease volume of battery, and ellect lhe perlormance of exposed plate to be serious cause ol inner shorting. So many troubles are experienced due to this cause. therelore it wouldn't be exaggeralion lo say that is the most part of causes 10 shorten it lile. Keep always in charged state. It used tor a long time in insullicieni charged slate trouble called sulphation Will be accelerated and ai last II inviies such dillicuity as lo make it hard to restore original suosiance by usual charging. Such pole plate warps easy to short. 01 the oiher hand. il used With thin solution due io over discharging separaior gets damage. Therelore it is requested lo supplement change belore the discharge limii. (Fig. 2—8~27l01 asisuimm mum 'wu-nwvvrm _ .wua._..w,mi,w .. Mame-W.” . .sui...w.-s...l.,a. , «am-«.- ,mmc. an. an». it. ms... 5 D4- '- w - W w "v. can...“ imiwiniiisiam wW-MW'NH‘W" , M Mm). M. W. .0... ' ’ ‘ «m». ...i m s. o.- m ms. war co, m: .o...».w.....iu 54 , a“? mom on; ma Fig. Z—IO. Frecuul‘ion lor use 160 For the battery. MBJ4—12 type (Voilage 12V. volume 10 hours rate lOAhl is applied. Duration of battery is expressed by hours lrom the complete charging slate to the complete discharged state using electricity lor each separate loading while in stationary slots. Therelore it the loading overlapped duration will be shorten so much, This relation could be presumed hum the lollowing table. londs or loading on bottery Standard ”eagf’ui‘vi’gf'm" Dufiggrogfmggfery Head light 35/35W i a A 2 his Starting motor 0.4kw io~soA Listed on other 90" Magnetic starlet switch 7 3,5A Listed on other part Neutral lamp 3w 0.25A 40 hrs Winker lamp 10W x 2 1A 10 his Tail light 4 w 0.35 A 30 hrs Stop light aw 0.7A 7 Speedometer lamp an 0.25;: 40 hrs ignition Stop — * 3.5 A 1.6 his Running — 0.5~L2A — Harri iOOP LEA Shvs s in case or point ciussed and switch on For instances, it the head light 35W is on, consumption is 3A only and duration Will be about 2 hrs. but it the taii lamp (0,35Al and ignition [3.5Al were used simultaneously total consumption Will be 6.85A. From the ligure above shown duration becomes 35—40 minutes. While in running, charging is done corresponding to engine revolution, so that dillerence between charging and discharging current will behave charging or discharging. Charging curreni>dischorging current “charge bottery Charging current< discharging current Hdischarge battery Especially as large current flows while in use ol starting motor. it is required m control less thon 5 seconds for one action, alter that takes rest 10~15 sec. 10 repeat next action. There occurs rapid drop of voltage if large current taken out lrom the battery but it restores the original voltage it taken a rest. . Therelore continuous pushing on the starter button causes voltage drop preventing restoration to the ellect of early exhaustion. iéi \Al Dnchurgc current W fig? , 7 iHi.Duranon __.riu th. 2—11. Reiation oetween discharge current and duration lur M31 442 type 112 V, 1OAH] battery (t1 Selenium rectitier ® Dynamo :J, Battery @ Fuse connector ‘ 0' ts, me 15A i‘ Red 2. Dark brown 3 Vellow 4' White 5' Black 5‘ White red spirai 7‘ Eanh to irenie 5, ”7727' Fig. 2-12. Charging current circuit diagram D. Starling Molar 0) Starting Circuit The starter sWitch of push dotton styie Is equipped on the righr side at the handle. Pushing it, the starter magnetic switch Is operated to teed current of about 100A to the starting motor trom the battery tar Model C72, 77, and about 60A tar Model C572, 77 to rotate the starting motor. The starting motor is equipped in tmnt ot the crankcase and the crankshatt is rotated by starting chain through the dverrunning ciutch trom the dynamo side. 162 2, r1 ® lootiCD LJ 4 iiiiiiiiI Starter switch Combination witch Starting motor Starting molar cable Starter magnetic switch Starter battery cable Battery Block red spiral Yellow red spiral a®§7®©9 I ©M@L-l ® L Fig. 2—13. Wiring ol starting motor q) Brush (7‘, Ball bearing ® York Q) Bnish spring Sprocket shah ® Armature ® Field coil @ Sprocket {3, Cover band (A) Pale core (13 Gear housmg GE Commutator (5; Terminal mi Planetary gear 67‘, Commutator end lrame [riterrioi gear b) Reduction 01 starter ® Center bearing holder Fig. 2—14. Starting motor @ Bearing bush To get required torque and revolution to rotate the crankshalt by reducing revolution ol the motor mechanical reduction is necessary 163 To complete (his in high weight the primary reduction is done by planetary gear and turther the secondary reduction by starting cho'iri. Primary reduction ratio 5.78 :I [planetary gear] Secondary reduction ratio 2.77 :i lchainl Total reduction ratio 169 As the starting motor does not run constantly there seldom occurs wear but to prevent moisture its construction is closed type. Theretore alter each 5.000~l0.000krn run the tollcwing points should be checked with case (D Check wearing on carbon brush and commutator. (2) Eliminate carbon powder (blow off by compressed airi. Supply grease in the gear case. it required by any reason to take out the starting chain. do not disassemble the starting sprocket trom the motor. By any chance it the starting sprocket were taken out it is necessary to disassemble , _ (I) Internoi 990' ® a 0® ® Planetary gsal 0 , ® ‘ (a: Sprocket shatt » _ y I (Q Sprocket Fig. 2-16. starting motor Mmched on engine 164 @ Planetary gear ® Motor shah @ Internal gaur @ Sprocket shalt (5‘; Sprocket Flg. 2—17. Reduction niemanism were taken out it is necessary to disassemble even the plonelory gear and the starting sprocket should be combined pelore reassemble the starting motor. ll tne sprocket were set in, Without disassemolying the starting motor by mistake there happens rotation impossible due to hitting against the case by the planetary gear. (Fig. 2—l5~2—l7] cl Dismounting the starting motor a. Take off the starting motor cable lrom terminal. b. [nasal] each two screws ol 6mm tightening the starting sprocket cover and take of! the cover. 1:. Loosen two screws of 5mm on the starting motor side cover and take off the side cover. d. While loosening 4 bolts ol 6mm fined on the crankcase and taking out the starting motor lrom the engine case, it will be separated lrom engine by removing the starting sprocket lrom the chain. (Fig. 2718) 155 E. 'l . Maintenance ol the Starling Motor Hemovai ot the carbon brush a. Take on the cover bond complete of the commutator b Loose 2 bolts fitted on the Commutator end irame and take it out c. By taking out the carbon orush pressing spring. take out the carbon brush loosening the connecting screw 07 [he held Coil and Carbon brush. \ ~ Mica piece Commutator (Coppeii ® Motor shuit Flg. 2-19. Crossrsection or commuiamv 2. Commutator The commutator is as shown in Fig. (A) wniie in use copper pant get wear to turn like (B). In such cases it is requested to adjust to be (AI It is advisabie Io reiy on specialist shops as this adiustment requires highiy tecnnics (under cutting of mica). Fig. 2—19i ® Ac Generotor rotor @ Starting clutchrouter C?) 10.2X115 rclier rig. 2—29, Generator starter and swning clutch 3. Over running ciutcn This transmit rotation trom the starting motor to the crankshatt. out reversaliy trom tne cranksnatt coin not rotate the starting motor. This construction is quite same With Model C72. (Fig. 2720) 166 I. ll lurns lhe slarting motor a. When lhe slarting chain is pulled along lhe direclion ol arrow as shown in the picture. b. By rolating the sprockel. the clutch outer is turned when the roller is ioined with the starting sprocket and the clulch outer moving to the narrow side. Accordingly lhe dynamo rolor is turned which is fixed with the clutch outer as one unit. 6. On the rotor is iixed on the crankshalt by a key oi 4mm rotation oi the clutch ouler is transmitted on lhe cronkshoit. cl. The starting clutch roller spring is uselul lor smooth running ol roller without any irregular meshing. Furthermore a spring cop is used to make smooth molions ol lhe slarting clutch roller spring and the roller. 2. When lhe engine sians running a. Rotational speed ol the crankshali becomes taster than ihat ol the sprocket. b. Transmission irorn the slarting motor is cul, due to centrllugal lorce on lhe roller which presses the spring and moves to the Wider space ol the clutch outer. Fig. 2-21. Picture showing principle ol iunclion oi the. overrunning clutch lAl Fig. 2-22. Picture showing principle ol lunction ot the overrunning ciutch (El 167 Luorication Lubricationslor the over running clutch is done by oil dropped through the hole (Al in the ligure which passes through the groove at three parts (B) and starts inside ot the inner oil seal 2035 at 20mm bush and the lock oil seal 326575 to prevent burning. Theretore alter disassembly it is necessary to clean oil holes (A) and (Bl by coma pressed air. Precaution about maintenance As lite ot the over running clutch depends on the tunction é roller, special attention is needed for its handling. a. Grease put on the roller should be used designated one. lParl No. 7191]], Silicon grease} This designated grease have several leatures. that is high resistant to cold and hot (740°C~200°Cl, least variation tor lrictions coetlicients due to temperature and other variation. Betore putting this grease cleanse each port by gasoline. and alter drying up, paint grease thinly all over the surlace ol the roller. o. Be carelul about magnetic torce Not only roller or roller spring. but also parts around the clutch should be avoided lrom magnetizing. Any time resistance will unlovombly atleci smooth running of roller. no. ' Pan name i Ouanltlv No Port none Quaniiry 1 Starting chain I l 8 ‘ Cross hole sdew 3 2 Starting sprocket r it 7 9 ‘ Hallow key Helge! 7 ‘77 3 Roller / 7 737 107 R crankshoti l 4 7 Clutch outer W 7 i r ll Plush ‘ l . Starting clutch roller r i2 7720305 oil Suzi ‘ l7 to swing (up is 325275 lock out seal i seamhg dulch roller , spring . 14 P, (tank bearing housing l 7 A.C dynamo rolov l 15 Z beating l léfi F. Starter magnetic switch Current to rotate the starting motor Will reach about 100A, To reduce resistance big Wire is needed, and also the switch to make on or off should be larger size at the contacting part. Accordingly it Will he ditticult to lino such place as easy to operate switch. teeding current directly on the starting motor. In such cases, sWitch utilizing magneto can be equipped at the most convenient place between the battery and the starting motor and put the switch to operate this magneto separately to make possible remote control With least current. 1. Principle oi tunction al If current flows on the primary side, an electromagnet actuates to attract iron core resisting spring torce. b. The contact point at the end at the iron core connects the secondary circuit. (Fig, 2—241 Fig. 2—73. Starter magnetic switch (1‘ Magnet coil (primary mill 0, Contact [operating sldel ® Terminal @ Contact (Fixed ride, secondary sldei Contact return spring Fleturri spring ', MoVing core Fig. 2-24 Construction at starter magnetic sWitch 2. Frecaution a} When put voltage of 12v petween both terminal ot the primary circuit, if heard cracking sound, the contact point at the primary circuit is connected. 169 bi If used lor a long lime. contact poinl gels were and damage lo increase resistance. and sometimes no currenl flows (even ii sound of cracking is heard, somelimes the starting motor lorced lo slopl. In such cases. disassembie it and poiish the contact point wilh a file or a sandpaper. To disassemble lake lhis switch lrom the body. c) Operalianal currenl on the primary Side iess than 12V, 3.5A. (Fig 275, 2-61 vs: C %= 0 "00‘000 in: l magnetic swncri (assemble purl! Fig.3 25. _ Disassembi 170 3. PARTS FOR USE OF SAFE GUARD Speedometer, Tachometer For Model C72, 77 is equipped only a speedometer but not a tachometer. The speedometer is generally magnetic type, and rotation proportional to that of the wheel is transmitted to the speedometer by means oi a flexible cable. For the tachometer, magnetic tachometer is used alike the speedometer and rotation proportional to that ol the cam shalt in the cylinder head is transmitted to the tacho. meter. (Fig. 3-1) Flg. 3-1 Speed lochomslel mi Fig. 371 Dial all Speedrlachomeler The speedometer is consisted at speed indicator and distance meter. and speed is expressed by km/h, and running distance IS integrated up to 99.999 km by the distance meter. The tachometer shows revolution number per minute by indicator (norm! Constructionaiiy it is same type wtth speedometer and stored in the same case of the speedometer. Only ditlerent points ore thai no integration mechanism and dmerent sign and measures on the dial plate. 171 Construction ol the speedometer and tachcmeter ls shown in the ligure The rnagnets rotate with some rotational speed with that of the flexible cable and the induction disc iof aluminium or copper mode) moves with indicator as one unit. The magnet shelter disc lurnishes magnetic field to generale eddy current on the disc by the rotating magnet. ® Diol ® induction disc ax'ls @ indicator (9 Hair spring (5) Magnet sheller disc lchurcoai disc] @ induction disc (77 Magneto Fig 3—3. Principle ofspeedometel Fig 34. Parts or speedometer ® No. l shalt ® No. 2 shalt ® No. 3 shalt a; No. 4 shalt 69 No. 5 she‘d oi Magneto ® Magneto sheller disc i3 indication disc Total Fig 3—5. Construction at Iomi distance metel 172 By means or this eddy current the magnet shelter disc is moved by proportional revolving iorce to the magnet and indicator shows (It the dial balancing With reaction at the correctly adiusted hair spring. When the cam is stopped. (on the tachometer, engine is stoppedt the indicator and the induction disc come hock to the zero by restoring iorce oi the hair spring. For the speedometer revolution oi the irdnt wheel is reduced in the gear box, and the cable turns i400 revolutions per 1 km running, on the other hand ior the tachometer. revolution of the cam shalt is reduced iurther. Reduction ratio oi the tachometer axis to the crankshait is 3-20. lfig. 3—41 Total distance meter reduction JIS Regulation T Flexible Reduction Speedometer we shall ratio indication 1W0 or m whee, m, 1400 i/uon } 60 hit/h wwheci cur 637 1/637 i 60km/h The distance meter is shown constructionally on Fig. 375, this magnet shait cutted worm on it transmit its rotation as No. 275mm No. Sishafl No. 4Hwheei No. Siwheel reducing each speed. ()1 the dial oi the total distance meter iigures as O, i 2. ..9 are marked, and teeth are cut so as to rotate each wheel ior one turn, the succeeding wheel roloies ‘r'ii, revolution. (Fig. 3—51 MEMO ‘73 TROUBLE SHOOTING TROUBLE SHOOTING Procedures of diagnosis Ior Iinding out causes of trouble and their probable causes are discribed as follows : 1. Engine does not start or hard to start Ill Remove the corburelter float chamber and check for Iuel flow, it Iuel is not supplied enough; l—l. Clogged Iuel line 172. Clogged fuel tank cap vent hole 1-3. Clogged fuel cock 1—4. Clogged carburetler line or stuck needle valve (21 Remove the spark plugs, attach them to the spark plug caps. turn in the ignition switch and rotate the crank shaft With starter motor while the (—I electrods are grounded. ll the spark plugs do not spark well or nil; Q—L Faulty spark plug, Ito make sure, check the spark plug with spark plug tester.) 2—2. Sooly or wet spark plug 2—3. Contact breaker point 2.4. Faulty condenser 2.5 Incorrect adlustment of contact breaker point 2-6. Short circuit or breakage in ignition coil or wiring 277. Damaged combination switch (3] Check compression pressure at the cylinder with a compression gauge and if lack or nil of compression is indicated in either cylinder; 3-]. Incorrect tappet clearance 3_2_ Incorrect seating of valves in valve seals 3-3. Excessive wear in valve 3,4. Excessive wear in piston ring, piston cylinder 3_5_ Blown out cylinder head gasket 3-6. Seized valve in valve guide 347, Faulty valve timing (4i Start engine following the procedure of starting but engine seems to start but won’t continue running; 4-]. Too Wide opened choke shutter in cold weather 4_2' Wide opened air screw of carburetler adjusting air-screw 4A3 Damaged carburetler insulator or gasket I77 2. Engine does not develope lu|l power (ll (2] (31 141 (Si 161 (7} Stand the motorcycle on the main stand and rotate the rear wheel by hand when the charging gear is set in neutral, il wheel does not turn easily; 1—] Dragging rear brake-incorrect odivslmanl 1—2, Damaged wheel bearing i—3‘ Too tight drive chain tension, in correct adjustment Check the tyre air pressure and inllate to the specmc amount. Check the clutch lor slip and if It IS lound slipping; 3-I. Improper odiuslmenl of clutch 3-2. Worn clutch facing 3-3. Weakened clutch spnngs Measure the highest revolutions ol crankshalt With a revolution counter and if the engine does not develope lull revolution; 44. Choked carburetter at somewhere 472 Clogged air cleaner 4—3_ Insulllcient supply of luel to the intake 4~4_ Clogged mulller 4—5_ Faulty ignition coil or contact breaker points 4-6. Faulty seating of valve 4—7, Incorrect ignition timing 4—8, Excess weak valve springs 4—9, Faulty spark plug; test the spark plug with spark plug tester Check oil level in the crankcase and udiusl the level to the specillcatlon, or excess amount of fill result In the trouble. Inspect lor excess heating of engine and ll lound it same; 6-'l_ Excess carbon deposit in combustion chamber 6—2. Inlerior grade ol luel IS used 673. Slippery clutch 6*4. Lean air-luel mixture ; improper size of mam let in :orburellel 6~5_ Dirty cylinder and cylinder head Check lor the engine developing or knocking when it submit to quick occerem‘ “an or successive running at high speed and If it is so; The probable causes are came as No. 16). 17B 3. Engine runs erratic and/or Wlth miss tirlng (ll (2] Adjust alr screw of carburetter properly and still runs under same circumstances. lil. Faulty ignitlon timing 1—2. Damaged carburetter insulator or packing 1*3. Faulty spark plug 1-4. Faulty condenser 'l—5. Faulty ignition coil 7-6. Faulty contact breaker point l—7. Incorrect tappet clearance Check for mlsslng at high speed and if the engine is still under the same. 2—]. Insufficlent supply of fuel 2-2. Incorrect valve timing 2—3. Damaged orweck valve springs 2—4. Other causes mentioned in N0. ll! 4. Excessive oil consumptlon or exhaust blue or black smoke (ll It the engine exhausts smoke whlle continuous running at high or low FFM 'l—l. Worn cylinder or piston nngs 1'2. Reversely assembled rings in piston 173. Excess clearance between exhaust valve and guide It the engine exhausts smoke iust after when closlng throttle valve suddenly trom certain opening,- 2—1. Excess clearance between lnlet valve and guide 2,1 Clogged alr venl hole or plastic tube 5. Clutch ierks or engages unsmoothly ll) |f the machine moves oft with ierking or the englne stops at the moment when the clutch engaged. l~l. Uneven tensions ot clutch springs lea Distorted clutch plates or faclngs 1_3‘ Sticky movement at clutch plate ln the clutch outer 6. Gear shlftlng does not operate correctly [ll When the changing gear does not engage. l-l. Worn notch on the shltt drum 1—2 Stuck shift tork to the shitt drum 173. Worn shltt tork I79 {2) lflhe gear jumps uul while running; 271. Worn dogs on the gear shifter 2»2. Worn or distorted shirt fork 2*3. Weakened shill drum stopper spring 7. Engine runs wilh unusual noise when the tappel clearances assumed correclly: iii If knocking noise is heard lrom cylinder when accererotrng engine 1—1 Excess clearance belween cylinder and prslon ‘21 If chatlerrng noise rs heard even if the com chain has been adlusted; 2-l Excess worn cam chain 272. Excess worn cam chain lensroner spring or roller (Si When knocking noise is heard lrom crank case 3*], Worn crank shall big end 3-2. Worn crank shall bearing [4] ll the clulch incures nurse when operating clutch lever. 4—1. Excess clearance between the clulch plale and clulch uuler 4—2 Excess clearonce belween lhe clutch cenler and clutch plate 8. Troubles in sleerrng (I) ll ii is tell lhul the steering is hard at turning: 1'1. Over-tight steering boll races 1’2. Damaged steering 1-3. Bent steering stem (2] Steering wanders or pull to one side while running. 27], Worn from and/or rear wheel bearing 2»2. Distorted lrunl and/or rear wheel rim 2*3. loosen spokes 274 Worn rear fork pivot bushing or from arm pivot bushing 2*5, Bent front fork or lrome or reor lurk 2-6. lncorrecl rear wheel alrgnmenl 3—7, Uneven slrenglh or cushion springs m both srde 9t Troubles of brakes (r) The brake does not acluqte properly even aller the free play is adjusted correctly 1-1 Worn broke shoes 150 (2] 1-2. Worn brake cam 7-3. Worn brake pedal shaft 1-4 Brake shoe eontammaled wilh oil or water 1-5, Sluck brake cable or rear brake link 1-6. Lack o1 grease in brake cam Brake squeaks when applied. 2-l. Excess worn brake shoe 2-2. Contaminated surlaee of brake shoe 2—3. Warped or pitled waH of brake drum 2-4. Excess wear 0! brake panel spaeer 18] HONDA 2500300 MODEL C72, c71,cs72‘cs77‘cn72‘ CI77 SHOP MANUAL HONDA MOTOR 00., LTD. M DEPAR‘IMENT. rower: SALES DIVIS‘ON as 5‘ Yuesu. Chuorko. Tokyo Japan Primed by VAMAGATA PRIN‘IING c0.. up. $173. Tfllflsmmardorf‘ NEW-km Yumhumn‘ Japan June 1955