Yamaha YBR125 Custom Service Manual Download Page 49

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INSP

ADJ

Check of compression pressure

Note:

Insufficient compression pressure wil result in the
performance loss.

2.
3.
4.
5.

Check:

Air valve clearance

→

adjust

Refter to "adjustment of air valve"

Start and warm the engine for several minutes.
Stop the engine
Remove:spark plug
Install:

Pressure manometer
Joint

Pressure manometer:90890-03081

Joint:90890-04082

6.Check

Compression pressure

Measurement steps:

Crank over the engine with the electric starter or kick
starter with the throttle wide-open until the compression

reading on the manoeter reach to the max.value,then

read the max. one.
Check readings with specified levels.

When compression pressure

Poor air valve contact will cause compression

leakage.

Adjustment of air valve clearance is poor
Piston,cylinder and piston ring will be worn out

When compression pressure is too high

A The burning room of cylinder head will have

carbon deposit

B Piston head will have carbon deposit

B
C

Standard compression pressure:

1200KPa( 12kg/cm)

Install:

Spark plug,spark plug cap

3 - 10

Summary of Contents for YBR125 Custom

Page 1: ...YBR125 JYM125 125 2 Chongqing Jianshe YAMAHA Motor Co Ltd First edition Jan 2003 All rights reserved Copy in any manner in whole or part or use without written authorization of company prohibited ...

Page 2: ... striving to improve all its models Modifications and si gnificant changes in specifications of procedures will be forwarded to all authorized dealers and will appear in future editions of this manual where applicable Note Design and specification are subject to changes without notice Important Information Warning Particularly important information is distinguished in this manual by the following ...

Page 3: ...he exploded diagram is provided at the beginn of each exploded chapter A clear exploded diagram is used for disassembly and reassembly of the motorcycle In the exploded diagram the numbers as symbols is used for explaining the removing procedure If there around the numbers it is the explanation of disassembly procedure Symbol in the exploded diagram is the explanation of work and key points For th...

Page 4: ......

Page 5: ...Index 1 General information 2 Specification 3 Periodic inspection and adjustment 5 Carburetor 6 Chassis 7 Electrical system 4 Engine 8 8 Troubleshooting 7 6 5 4 3 2 1 GEN INFO ADJ ...

Page 6: ...ection and adjustment of air v alve clearance Adjustment of idle speed Drainage Check and adjustment of free play of throttle cable Check of spark plug Check of compression pressure Check of lubricating oil quantity of engine Replacement of engine lubricating oil Check of lubricating oil pressure Check and adjustment of clutch Check and clear of air filter Adjustment of front brake drum rype Check...

Page 7: ...ar Di sassembly of shift axle Disassembly of rotator Disconnection of crankcase Disassembly of balance device transmission and shift rod Disassembly of crank balance block Disassembly of rocker arm camshaft Disassembly of air valve Cylinder head Air valve seat Air valve and guide pipe of air valve Air valve spring Camshaft Rocker arm and rocker arm shaft Timing chain sprocket guide plate of chain ...

Page 8: ...n Cylinder head Cam axle and l ocating key General drawing of carburetor Removal of carburetor Adjustment of fuel level Inspection of front and rear wheels Front wheel Inspection of front wheel Speedometer gear assy Front brake Installation of front wheel Rear wheel Rear brake hub Drive chain sprocket Drive chain Inspection of drive chain Assembly and adjustment of engine Chapter 5 Disassembling o...

Page 9: ... and rear arm Removal Inspection General drawing of circuit Electric components Inspection of socket connector Inspection of switch Ignition system Starting system Starting motor Charge system Lighting system Signal system Electric appliance system Compression system Intake and exhaust system Front fork Chapter 7 Circuit Chapter 8 Troubleshooting Troubleshooting of engine 6 17 6 18 6 19 6 22 6 23 ...

Page 10: ...Chapter 1 General information Motorcycle identification Motorcycle identification code Points for attention in maintenance Special tool ...

Page 11: ...three portions First portion the first 3 digits is the identification code of world manufact urer identification WMI Second portion 6 digits is vehicle definition section VDS Third portion 8 digits is vehicle indication section VIS Engine series No Engine series Nos is stamped on the crankcase Engine stamping code JYM154FMI 00000001 Note Design and specification are subject to changes wit hout not...

Page 12: ...1 GEN INFO ...

Page 13: ...1 GEN INFO ...

Page 14: ...Note Do not use compressed air to spin the bearings dry This will damage the bearing surfaces 1 GEN INFO ...

Page 15: ...1 GEN INFO ...

Page 16: ...1 GEN INFO ...

Page 17: ...gine 2 1 2 4 2 4 Chassis Electrical system Main tighten torque specification Position to be applied lubricating oil and kinds of lubricating oil 2 6 2 8 2 9 2 12 Engine Chassis Engine lubrication diagram Layout of cable pipeline 2 12 2 13 2 14 2 16 ...

Page 18: ...2 2 2 YAMALUBE four strokeSAE20W40SF or SAE10W30SF machine oil Machine oil type Engine oil ...

Page 19: ...sh 5 speed shift Left foot operation 68 20 3 400 45 14 3 211 37 14 2 643 32 18 1 778 25 19 1 316 23 22 1 045 21 24 0 875 Diamond 26 4 With tube 2 75 18 42P 90 90 18 51P 175kPa 1 75kgf cm 196kPa 2 0kgf cm 2 2 Drum or single disc brake Right hand operation Drum brake Right foot operation ...

Page 20: ...ectrical system Ignition system Generator system Battery type Battery capacity Shock absorber Front Rear Suspension Front Rear Retractable sleeve type Rocker arm type 12V 35W 35 1 12V 21W 5W 1 12V 1 7W 4 14V 1 2W 1 12V 4W 1 14V 3W 1 14V 3W 1 14V 3W 2 12V 10W 4 Bulb type Incandescent bulb CDI A C magneto 12V5Ah 1290mm Coil spring oil damper Coil spring oil damper Immediately use JYM125 JYM125 2 2 3...

Page 21: ... 4 950 4 935 2 0 08 0 12mm 0 10 0 14mm ...

Page 22: ...5 000 5 012mm 5 000 5 012mm 0 010 0 037mm 0 025 0 052mm 2 ...

Page 23: ...2 ...

Page 24: ...side dia thickness Use limit of disc thickness Thickness of brake pad Inside Outside Master cylinder inside dia Long pincers cylinder inside dia Appointed brake fluid Type Inside diameter of brake drum Thickness of brake shoe Free length of brake shoe spring Driving chain Type manufacturer No of links Twist quantity Spoke casting wheel 1 85 18 W 5 5 10 5mm 10 15mm 20 30mm disc drum Drum type 130mm...

Page 25: ...2 7 N ...

Page 26: ...ead holt Hexagonal flange faced bolt Hexagonal flange faced nut Hexagonal flange faced bolt Hexagonal nut Hexagonal bolt Internal hexagonal cylinder head bolt Hexagonal flange faced bolt Cross recess bolt Bolt Internal hexagonal cylinder head bolt Hexagonal flange faced bolt Hexagonal flange faced bolt small head Hexagonal flange faced bolt small head Hexagonal flange faced bolt small head Hexagon...

Page 27: ...ing shaft and circular nut Handle bar and its seat Caliper and front fork pan Front main cylinder and handle bar pan Front portion of engine and support 2 of engine Support 2 of engine and frame Rear portion of engine and frame Upper portion of engine and support3 4 of engine Support3 4 of engine and frame Rotation shaft and nut Rear shock absorber and rear arm Rear shock absorber and frame Pullin...

Page 28: ...5 0 8kg m 12 19Nm 1 2 1 9kg m 24 39Nm 2 43 9kg m 45 72Nm 4 57 2kg m Width of two faces Dia of thread Pitch of thread Tighten sequence of steering system 2 3 4 5 1 Tight the nut of to30 35N m Then turn the steering bar 2 3 times by leftward and rightward In turing binding and loosening of bearing race is not allowed Loosen nut of by1 4turn and then tighten it with tighten toque of 20 24N m Turn the...

Page 29: ...ng Valve stem End of valve stem intake exhaust Rocker arm shaft Cam and bearing cam shaft Inside of rocker arm Left and right closed face of crankcase O ring all Inside of foot pedal gear Inside of idle gear of foot pedal Crank sleeve of foot pedal Axial surface of starting idle gear Start clutch outside rotating portion Gear inside of starting wheel Pushing rod Inside of main driving gera Shaft o...

Page 30: ...ation face of clutch lever and holder Contact face of brake cable and holder lever Rotation face of brake lever and holder Inside of brake pedal Main support and its rotation shaft Rotation face of side support and its holder Rotation face of rear footrest Meter gear Cam and shaft of cam shaft Rotation portion of brake pad pin Lip portion of oil seal of hub assy clutch assy and brake cover assy YA...

Page 31: ...2 Rocker arm intake arm exhaust Cam shaft Rocker arm shaft Rocker Lubrication diagram Centrifugal filter Oil pump Pushing rod Filtering web 2 14 ...

Page 32: ...2 ...

Page 33: ...ss through the inte rior ofbattery F Flowing guide tube of battery shall pass through the interior of battery G Fix the wire of magneto and brake switch at the wire clip H Pass the brake cable and flexible shaft of meter though guide frame Drum type without fairing ...

Page 34: ...2 Layout of cable pipline Drum type without fairing ...

Page 35: ...witch and handle bar switch through guide frame B Pass the wire of clutch cable handle bar switch and clutch switch through guide frame C Fix the wire of left handle bar switch and clutch switch with bands D Fix the wire of right handle bar switch and brake switch with bands Drum type without fairing ...

Page 36: ...2 Layout of cable pipline Disc type with fairing ...

Page 37: ...2 Layout of cable pipline Disc type without fairing ...

Page 38: ... of front brake switch Brake cable Wire of right turning light Throttle cable Wire of right handle bar switch Wire of left turning light Wire of clutch switch Wire of left handle bar switch Clutch cable Fig A 1 2 3 4 5 6 7 8 9 2 21 ...

Page 39: ...t pressure Check and adjustment of clutch Check and clear of air filter Adjustment of front brake drum type Check of front brake shoe Check of front brake disc type Check the brake liquid quantity Exhausting air Replaceing brake liquid Checking adjusting rear brake Checking adjusting rear brake light switch Checing adjusting driving chain Check of front fork Adjustment of rear shock absorber Check...

Page 40: ...uel hose for cracks or damage replace if necessary Repace warm engine before draining l Clean or replace Check operation brake fluid leakage refer to the remarks Adjust if necessary Check operation Adjust if necessary Check operation adjust if necessary Check swing arm assy for looseness tighten if necessary Repair if damaged Check operation Disassemble to repair if necessary Check the bearing for...

Page 41: ...eration Correct if necessary Check prior to driving Items It is recommended that these items be serviced by YAMAHA authorized service station or dealer Heavy duty or medium truck wheel bearing grease Lithium soap base grease Remark Replace brake fluid 1 2 3 If disassembling brake master cylinder or long pincers cylinder the brake fluid must be replaced Check the The oil seal of brake master cylind...

Page 42: ...row 3 Side cover of guide flowing right Take out the bolt of seperate the connecting block which connects side cover then pull out the set pin of side cover finally take out the side cover along the direction pointed by arrow 4 Side cover of guide flowing left Take out the bolt of separate the connecting block which connects side cover then pull out the set pin of side cover finally take out the s...

Page 43: ...onduct as per reverse procedure of removal operation pay attention to the following 1 Installation Fuel tank Torque Bolt torque see upper fig 2Kgf m 20N m 2 Installation Cushion Note First insert the convex tip position at the rear portion of cushion into insert hole on the frame then install the bolt of cushion into every hole seperately finally tighten the nut Bolt torque see fig 1Kgf m 10N m 3 ...

Page 44: ...earance when the piston is at the Top Dead Center T D C on compression stroke 1 Remove the following parts Side cover left right Cushion Fuel tank Refer to removal and installation of cushion fuel tank and cover alike 2 Remove the following parts Side cover of cylinder head bolt Spark plug Rocker arm cover Intake Rocker arm cover Exhaust 3 Remove the following parts Cock with O ring Cock with O ri...

Page 45: ...rance IN 0 08 0 12 mm Ex 0 10 0 14 mm Conduct adjustment for the valve under standard value Adjusting sequence Loosen fix nut Insert feeler gauge Install the air valve adjusting tool on the adjuster a Turn the adjuster util the standard value is obtained To n avoid the adjuster turn together fix the adjusting tool before locking the set screw Confirm the air valve If it is out of standard value re...

Page 46: ...idle speed rpm Standard idle speed rpm 1300 1500rpm Adjust if out of standard value 4 Conduct the following adjustment Standard idle speed rmp Adjusting sequence Turn the P S adjusting screw to the end slightlg Note Do not lock it tightly Ratate to standard rpm turns Standard rpm turns of P S adjusting screw 2 0 Start the engine Rotate idle speed adjusting screw leftward and right ward until the s...

Page 47: ...ter for CO content Check the CO density Standard co density 1 5 4 5 Out of standard value adjust P S adjusting screw match with adjusting idle screw Inspection adjust the free clearance of throttle cable 1 Conduct the following inspection Free clearance a of surrounding of throttle cable mm Free clearance of surrounding of throttle cable Out of specified value adjst 1 Conduct the following adjustm...

Page 48: ...ter adjustment start the engine turn the steering handle bar leftward and rightward confirm that the idle speed of engine will not increase Check of spark plug 1 2 Conduct the following check Check electrode pollution of insulation damage under burning damage under burning for deposits replace the pollutant and deposit clean with spark plug det ergent or steel wire brush Conduct the following chec...

Page 49: ... the engine with the electric starter or kick starter with the throttle wide open until the compression reading on the manoeter reach to the max value then read the max one Check readings with specified levels When compression pressure Poor air valve contact will cause compression leakage Adjustment of air valve clearance is poor Piston cylinder and piston ring will be worn out When compression pr...

Page 50: ...e engine with idle speed for 2 3 minutes then stop the engine for 2 3 minutes keep the machine in vertical position and take out cock Check the oil level on the cock if it is between and Lubricant quantity of engine Recommended lubricant oil When normally replacing 1 0L 1000mL When repairing the engine 1 2 1200mL Refer to the indication in the fig select the proper engine lubricating oil which sui...

Page 51: ...Filling in cock of engine oil Drain cock Gasket installed on drain cock Drain oil Add the engine oil from filling in cock Install Filling oil cock of engine oil Gasket installed on drain cock Drain plug Torque of drain cock 20N m 2kgkm Check of oil pressure 1 2 3 Remove oil pressure inspection bolt Start and run the engine for several minutes in idle speed Check Machine oil condition of overflowin...

Page 52: ...d Loosen the lock nut Screw in or screw out adjusting nut until the specified free play has been obtained Adjusting steps Screw in free play increased Screw out free play decreased 4 Tighten locknut Note If the free play is improper use adjusting device a part of clutch lever to adjust the free play of clutch cable 5 6 Loosen locking nut Screw in or screw out the adjusting device until the proper ...

Page 53: ...om of the air filter If dust or water collects in this hose clean the air filter core and case Note The engine should never be run without the air filter otherwise unfiltered air will get into the engine thus excessive wron out or damaging the engine will be resulted In addition the operation of carburetor will be influenced and engine may be overheated if running without core of air filter 3 INSP...

Page 54: ...ith high pressure air If the filter core 2 is too dirty it may be washed with neutral solution It must be blown dry after washing The filter core may not be painted engine oil Coution Coution It should be confirmed that the filter core has been fixed correctly in filter case Coution It is strictly forbidden to run engine without fitting filter core of air filter It will cause over wear of piston c...

Page 55: ...en up the lock nut Adjustment brake drum side Screw in or screw out the adjusting nut until reac hing specified free travel Check of front brake pad Screw in Free travel increment Screw in Free travel reduction Screw out Free travel increment 1 Check Needle wear indicating plate Needle reaching the wear limit line of indicating plate Replacing brake pad 3 16 Note Should confirm no blocking of brak...

Page 56: ... is vibration when turning leftward or rightward or driving you should check if the brake nose contact other part Contacting correcting Check the free play of the front end part of brake handle Free play of front end part of brake handle a 5 5 10 5mm Note This play is ensured by manufacturing No adjustment is needed Checking brake pad 1 Conduct following checking Check the wear condition of brake ...

Page 57: ...f it inmedinately when splashing Exhausting air Warning When disassembling related parts of braked liquid you must confirm that other parts are locked and sealed Then the air can be released Procedures 1 2 3 4 of releasing air Remove the cover of brake liquid vat Remove the diaphragm of brake liquid vat Mount plastic rubber pipe on front end of oil draining Screw and place a oil container at the f...

Page 58: ...d of plastic rubber hose Loosen the oil draining screw and repeat that several times until no brake liquid is drained by oil draining screw Wipe off the brake liquid sprayed on brake disk tire and rim 3 Lock the oil draining screw Oil draining screw 6 Nm 0 6 kg m 5 4 Remove the diaphragm of brake liquid vat Fill the brake liquid until above lower limit Appointed brake liquid genuine YAMAHA brake l...

Page 59: ...lowing checking Check brake and free play of front end part of pedal Free travel of frontend part of brake pedal 20 30 mm Unconformable to specified value Adjustment 3 Conduct following adjustment Free play of brake pedal Adjusting order Adjust the free play to specified value with adjuster Screw in Reduction Screw out Increment Check of rear brake shoe 1 Check Needle wear indicating plate The nee...

Page 60: ... Rear brake light switch Adjusting nut Checking adjusting driving chain 1 Conduct following check Support the motorcycle with main stand Check the slackness a of driving chain Exceeding specified value range adjustment 1 a Slackness of driving chain 20 30 mm 2 Adjust driving chain Loosen the lock nut of axle Loosen the lock nut of adjuster Screw in or out the adjusting device until reaching the sp...

Page 61: ...enance So per iodical checking and repair should be conducted which is especially important when driving under dusty condition Spraying type lubrication oil may be used Get rid of all dirts and mud on chain with brush or cloth Spray the lubricating oil onto the position between two side plates of chain and middle roller When washing chain remove the chain from the moto rcycle and immerse it into s...

Page 62: ...orber Warning Always adjust the preload value of each shock ab sorber identical to set constant value Uneven adj ustment will worsen the operation and reduce reliability Support the motorcycle firmly to avoid turning over 1 Adjust Spring preload Turn the adjusting device in direction a or b Turn in direct a Spring preload value increases Turn in direct b Spring preload vlaue reduces Adjusting devi...

Page 63: ...on of rear wheel 2 75 18 42P 90 90 18 51P 2 Check Tire surface Wear damage Replacement Min depth of tire thread front rear wheel 1 0 mm Repth of thread Side wall Wear indication layer Driving the motorcycle with worn tire is dangerous Replace the tire immediately when the tire is worn to line You would better not to mend the broken tire tube with rubber Mend the tire tube especially carefully if y...

Page 64: ...bar can be turned to left and right smoothly Loose steering axle unsmoothed turning adjusting nut of steering axle Conduct following adjustment Steering nut Disassemble steering handlebar Refer to Chapter 6 Steering handlebar Disassembling steering handlebar seat Lock the nut with steering nut wrench The locking procedures and method refers to Adjusting procedures Mount steering bar seat Mount ste...

Page 65: ...stilled water can be supplied The tap water contains mineral which is harmful to battery 3 Check Terminal of battery Dirty terminal cleaning with steel wire brush Bad connecting correction Note Paint a layer of little lubricating grease after cleaning terminal 4 Check Airflow hose Jamming Eliminating Damage Replacement Note Be sure to arrange the way of airflow hose correctly when checking battery...

Page 66: ...c gravity reading of one battery element is lower than others Obvious buckle or bending of electrode plate of insulator The electrod plate becomes white or substance gathers on bottom of battery unit element The battery electrolyte is damgerous It contains sulpharic acid which is poisonous and corrosive Must obey following preventing measures Avoid to contact electrolyte because it will cause seri...

Page 67: ...en take oxidized milk with egg or rapseed oil and see a doctor immediately The battery will produces explosive gas Following protecting measures must be taken Conduct chatging at ventilated place far away from welding equipment lighting cigaret etc Do not smoke when charging or work at battery The battery or electrolyte should be placed far away from children 3 28 3 INSP ADJ Check of battery ...

Page 68: ...Disconnection of crankcase Disassembly of balance device transmission and shift rod Disassembly of crank balance block Disassembly of swaying arm cam axle Disassemblyof air valve Cylinder head Air valve seat Air valve and guide pipe of air valve Air valve spring Cam axle Swaying arm and swaying arm axle Timing chain chair wheel guide plate of chain chain tensioner Cylinder and piston Piston pin Pi...

Page 69: ...m cam axle Crank balance device Transmission Shift cam shifting yoke Crankcase Shift axle starting axle idle gear Clutch engine oil pump Timing pneumatic system Rotator starting chain guide plate idle pulley Piston and piston ring Cylinder and piston Cylinder head Cam axle and locating key ...

Page 70: ...hion fuel tank and side cover Engine oil 1 Oil draining Engine oil Refer to section of Replacement of engine oil in Chapter3 Exhaust pipe 1 Disassemble Exhaust pipe Fixing bolt Carbauretor 1 Disassemble Carburetor Cable and guide wire 1 Disconnect Guidewire of neutral switch Guidewire of stator coil Guidewire of charging coil Guidewire of pulser coil 4 1 ...

Page 71: ...Shift pedal Disassemble Small chain gear Driving chain Kick starter Disassemble Nut Kick starter 1 Disassembly of engine Place a proper support under frame and engine or support the main stand and make it stable Disassemble Mounting bolt support of lower part of front side and engine Mounting bolt support of lower part of front side and frame 1 2 Note Loosen the nut of chain adjusting device and i...

Page 72: ...e Mounting bolt upper part of engine and support mounting bolt upper support and frame Disassembly of engine ENG Disassembly of engine Cylinder cover cylinder and piston Disassemble Spark plug Disassemble Intake divided manifold connecting pipe of cylinder and Disassemble Timing rotating plug 1 2 3 carburetor 4 3 ...

Page 73: ... procedure Rotate the crank counterclockwise with wrench 4 4 Make mark on rotator aiming at fixing needle b on crankcase cover When mark aiming at fixing a needle the piston is on upper dead center T D C At the same time the calibration mark c of cam chain gear should aim at calibration mark d on cylinder cover The swaying arms on both sides must form valve gap If there is no gap rotate the crank ...

Page 74: ...te Fix the timing chain with protective steel wire to prevent the chain dropping into crankcase 10 Disassemble Bolt Cylinder head Firstly loosen each bolt 1 4 turn After loosening all bolts remove them Loosen them successively from Min number The reverse order of the number st amped on cylinder means the order of tightening the bolts Note 4 5 ...

Page 75: ...Elasric circlip of piston pin Piston Note Before disassembling the cirlip of piston pin cover a piece of clean cloth on crankcase to prevent the elastic circlip dropping into crankcase Before disassembling the piston clean the groove and pin hole of circlip If it is difficult yet to disas semble the piston after doing that use disassembing tool of piston pin 4 6 ...

Page 76: ...tral light switch Disassemble Left crankcase cover Locating pin Seal papper pad Disassemble Starting motor 1 2 3 Clutch oil pump 1 Disassemble Kick starter device 2 Disassemble Crankcase cover right Seal papper pad Locating pin Note Firstly loosen each bolt 1 4 turn according to cross curve order then remove all bolts 4 7 ...

Page 77: ...r Pushing rod1 Steel ball Note Firstly loosen each bolt 1 4 turn according to order of opposite angle then remove all bolts 4 Flatten Smoothen the tongue of lock washer 5 Loosen Nut Note When loosening nut convex seat of clutch fix the clutch hub with clutch jig Universal clutch jig 90890 04086 4 8 ...

Page 78: ...riven gear Washer Elastic washer 6 u Disassemble Primary driving gear nt Do not place cloth strip aluminium plate and copper bar etc between main driven gear and primary driving gear see a Fix with sleeve at position of rotator fixing nut then disassemble primary driving gear nut Note 4 9 ...

Page 79: ...gine oil filter Engine oil pump 1 Disassemble Bolt Engine oil pump Gasket Driving gear of engine oil pump Starting axle and idle gear 1 Disassemble Elastic circlip Flat washer Idle gear Flat washer Elastic circlip 2 Disassemble Resetting spring Starting axle assy 4 10 ...

Page 80: ...e Rotator 1 Disassemble Nut Note Fix the rotator with rotator jig then loose nut 90890 01701 Rotator jig 2 Disassemble Rotator Half round key Note Push the fly wheel backward with disassembling tool of fly wheel then may disassemble the fly wheel Disassembling tool of fly wheel 90890 01362 4 11 ...

Page 81: ...e Chain guide board Timing chain Crankcase right 1 Disassemble Screw crankcase Note Loosen the screw at position as shown in Fig po sition in circle Firstly loosen each screw 1 4 turn then remove all screw If there is several bolts and nuts generally loosen them according to opposite angle order Loosening order from outside to inside 4 12 ...

Page 82: ... from right side Disassemble the shift cam star shape gear Be careful not to damage the matching surface of crankcase Balance device transmission and shift rod 1 Disassemble Guide rod of shifting yoke short Guide rod of shifting yoke long Shifting yoke C Shifting yoke R Shifting yoke L Shift cam 4 13 ...

Page 83: ...k and balance 1 Disassem le b Balance block Crank Disassemble with disassembling tool of crank 90890 01135 Disassembling tool of crank Tighten up the supporting bolt of disassembling tool but ensure the tool body vertical to crank When cessary screw a screw back ward a little to ca librate the tool body state Never beat the crank directly with hammer etc Note ne 4 14 ...

Page 84: ... pressure plate 2 Disassemble Camshaft with bearing Note Disassemble the camshaft with 8 mm bolt 3 Disassemble Rocker shaft Rocker arm Note Disassemble the rocker arm with sliding hammer bolt and weight block Sliding hammer bolt Weight block 90890 01083 90890 01084 4 15 ...

Page 85: ...ing working face of valv Valve seat and width of valve Refer to section of Check and repair of valve seat Checking procedures Inject the clean solvent into intake orifice and exhaust orifice Check the seal of air valve There should be no leakage at valve seat 2 Disassemble Lock piece of valve Note When disassembling valve lock piece compress the valve spring with tool Compressing tool of valve spr...

Page 86: ...isassembly of engine 3 Disassemble Upper seat of air valve spring Air valve spring Air valve Oil seal of air valve Spring Note Mark postions of each part in order to refiting them to oringinal position 4 17 ...

Page 87: ...Check Cylinder head Scratched marks damage Replacement 3 Measure The tilt of cylinder Check if there is skew at 6 directions of combinating faces with cylinder Gradient Less than 0 03mm 4 Repair the surface Cylinder head Repairing procedure Place a wet sand paper about 400 600 on flatform and grind the surface according 8 toshape Note Move the cylinder head several times to avoid too much wearing ...

Page 88: ...ve seat Intake 0 9 1 1 mm Exhaust 0 9 1 1 mm Meauring procedures 1 2 3 4 5 Paint blue dykem on working face b of air valve Fit the air valve into cylinder cover Push and press the air valve to air valve seat through guide pipe of air valve thus to get clear trace Measure the width of this mark which is width of air valve seat No matter wherever the air valve seat contacts working face of air valve...

Page 89: ...alve rod Fit the air valve into cylinder cover Rotate the air valve until the working face of air valve and air valve seat polish evenly Then wipe off all san ding agent Note In order to get better grinding effect when rotating the air valve forward and backward with hands you may beat the air valve lightly Paint fine sand agent on working face of air valve Then repeat above procedures Note After ...

Page 90: ...ceeding specified value range Replacing guide pipe of air valve Clearance between air valve rod and guide pipe Intake 0 01 0 037 mm Limit valve 0 08 mm Exhaust 0 025 0 052 mm Limit valve 0 10 mm 5 000 5 012mm 5 000 5 012mm 5 042mm 5 042mm Standard inner diameter Using limit Note After replacing guide pipe of air valve repair the sur face of air valve seat 2 Clean Carbon deposit clean from working ...

Page 91: ...r more than other part of air valve rod replacing 4 Measure Run out tolerance air valve rod Exceeding specified value range Replacement Run out tolerance Less than0 01 mm Air valve spring 1 Measure Free length a air valve spring Exceeding specified value range Replacement Free length of air vlave spring Standard 32 28 mm Limitation 31 90 mm 4 22 ...

Page 92: ...cle are not in horizontal conta cting state Replacement Camshaft 1 Convex part of cam Corrosive pitting scratch blueing Replacement Measure Convex part A and B of cam Exceeding specified value range Replacement 2 A B Length of convex part of convex part of cam Intake A Standard 25 881 25 981 mm Limitation 25 851 mm B Standard 21 195 21 295 mm Limitation 21 165mm 4 23 ...

Page 93: ...ing Replacing Rocker arm and rocker shaft 1 Check Contacting face of rocker arm and convex part of cam Adjusting device surface Wearing corrosive pitting scratch blueing Replacement Then check lubrication system 2 Measure Inner diameter of rocker arm a Standard value of inner diameter of rocker arm 10 000 10 015 mm Using limitation 10 030 mm Exceeding specification Replacement 4 24 ...

Page 94: ...e plate of chain and chain tensioner 1 Check Timing chain Hardening or crack Replace the whole set of timing chain and chain wheel 2 Check Sprocket Hardening or crack Replacing the whole set of timing 1 4 chain and sprocket tooth Correct assembly Roller Sprocket 3 Check Guide plate of chain exhaust side Guide plate of chain intake side Wearing or damage Replacement 4 25 ...

Page 95: ...nder and piston 1 2 3 4 Clean Carbon deposit from top of piston and ring groove Check Side wall of piston Wearing scratch damage Replacement Check Cylinder wall Waring or scratch Reboring cylinder or replacing Measure Clearance between piston and cylinder gauge at D3D4position 40 mm to cylinder top Measure cylinder diameter and C with cylinder Measuring procedure Note Measure cylinder diameter C f...

Page 96: ...29 mm Clearance between piston and cylinder Inner dia meter of cylinder Outer dia meter of piston Clearance Exceeding specified value Replacement Piston pin 1 Check Piston pin Blueing or becoming groove Replacing then checking lubrication system 2 Measure Outer diameter a of piston pin Exceeding specified value range Replacing Outer diameter of piston pin 14 991 15 000 mm Limitation 14 969 mm 4 27...

Page 97: ...on 15 043 mm Piston ring 1 Measure Side clearance Exceeding specified value range Replacing the whole set of piston and piston ring Note Before measuring side clearance get rid of carbon deposit in piston ring groove and each ring Side clearance 1 ring 0 03 0 07 mm Using limitation 0 12 mm 2 ring 0 02 0 06 mm Using limitation 0 12 mm Note Eject and push piston ring with piston to make the ring ver...

Page 98: ... u n o u t t o l e r a n c e l i m i t a t i o n o f c r a n k 0 0 3 m m 4 2 9 E x c e e d i n g l i m i t a t i o n R e p l a c e m e n t Ў ъ N o t e W h e n m e a s u r i n g t h e o i l r i n g e n d c l e a r a n c e d o n o t m e a s u r e a t p a r t i n g s l i p o f c u p r i n g o f o i l r i n g O n l y c a n m e a s u r e t h e e n d c l e a r a n c e o f u p p e r a n d l o w e r g u a...

Page 99: ...e calliper Standard width 46 95 47 00 mm Exceeding standard Replacement 4 Check Sprocket of crankshaft Damage wearing Replacing crankshaft 5 Check Oil way of crankshaft Jamming Clean by compressing a Bearing Abnormal noise unstable rotation loosening Replacing ir 4 30 ...

Page 100: ...Wearing damage Replacement 2 Check Balancer Wearing damage Replacement Clutch 1 Check Driving gear of spindle Driven gear of spindle Wear or damage Replacing two gears Loud noise while running Replacing two gears 2 Check Friction wafer Damage or wear Replacing the whole set of friction wafer 4 31 ...

Page 101: ... 4 Ў ъ 5 C h e c k C l u t c h w a f e r D a m a g e R e p l a c i n g t h e w h o l e s e t o f c l u t c h w a f e r M e a s u r e B u c k l i n g o f c l u t c h w a f e r E x c e e d i n g s p e c i f i e d v a l u e r a n g e R e p l a c i n g t h e w o f c l u t c h w a f e r S h o u l d u s e f l a t p l a t e a n d t h i c k n e s s g a u g e Ў ъ s e t ў Щ 6 C h e c k T h e l e n g t h o f...

Page 102: ...age Deburring of replacing Clutch hub Scratch wear damage Replacing clutch hub 8 1 Check Steel ball Pushing rod Pressing plate Wear damage Replacement Transmission and shift rod 1 Check Driven part of shifting yoke cam Shifting yoke jaw Scratch bending damage Replacement 4 33 ...

Page 103: ...damage Replacement 3 Check Guide rod of shifting yoke short on left long on right Shift cam Deformation scratch wear damage Replacement 4 Check Action of shifting yoke Uneasy action Replacing shifing yoke or guide rod Do not try to align the bending guide rod 4 34 ...

Page 104: ...placement Warning Do not try to align bending axle 6 Check Gear teeth of gear Blueing corrosive pitting wear Replacing matching gear Rounding of edge fracture dislocation Replacement 7 Check Shift axle Damage bending wear Replacement Torsion spring retainer lever Reset spring reset axle Damage Replacement 4 35 ...

Page 105: ... o r n d o u t e r r o t a t o r S i d e c l e a r a n c e B B e t w e e n o u t e r r o t a t o r a n d p u m p c a s e E x c e e d i n g s p e c i f i e d v a l u e r a n g e R e p l a c i n g o i l p u C l e a r a n c e C o f o u t e r i n n e r r o t a t o r a n d p u m p c a T h i c k n e s s d i f f e r e n c e o f i n n e r o u t e r r o t a t o r p u m p c a s e ў Щ ў Ъ ў Ъ ў Ы Ў ъ ў Щ ў Ъ...

Page 106: ...ine oil filter net Crazine damage Replacement Dirty Washing Crankcase 1 2 3 Rinse the combinating face of the crankcase thoroughly with a little warm solvent Wash all matching surface of gasket and crankcase th oroughly Check Crankcase Crack or damage Replacement Oil hole Jamming Blowing with compressed air 4 37 ...

Page 107: ... fi nger Uneven Replacement Note Do not dry it by making the bearing rotating by itself through blowing in compressed air Otherwise will cause damage of bearing surface 2 Check Oil seal Damage or wear Replacement Elastic circlip and washer 1 Check Elastic circlip Washer Damage loosening bending Replacement 4 38 ...

Page 108: ...rm and cam axle Lock piece of air valve Upper seat of air valve spring Oil seal of air valve rod Air valve spring Air valve spring seat Air valve spring rod exhaust Lock nut 14Guide pi 4 39 Adujstin S g bolt waying arm Swaying arm pin intake 11 Swaying arm pin exhaust 12 15Cam a 16Pressing p pe of air valve xle late NEW NEW ...

Page 109: ...il stone 2 Paint Molybdenum disulfide lubrication oil Painting on air valve rod and oil seal of air valve 4 stroke engine oil Painting on air valve rod top 3 Assembly Spring seat of air valve Oil seal of air valve Air valve Air valve spring Upper seat of air valve Note Make the side of large pitch a upward and mount the air valve spring b small pitch 4 40 ...

Page 110: ...soft hammer to fix it on air valve rod Note Do not boat it forcedly to advoid damaging the air valve Rocker arm and camshaft 1 2 Lubricate Molybdenum disulfide lubricating oil Painting on the confacting face of rocker arm hole and camshaft 4 Stroke engine oil Painting to rocker shaft and O ring Mount Rocker arm Rocker shaft Aim at screw hole of cylinder head to mount until the rocker arm can not b...

Page 111: ...Assembling and adjustment of engine ENG 3 Mount Camshaft 4 Mount Pressing plate Bolt 4 42 ...

Page 112: ...Assembling and adjustment of engine ENG Crank and balance device Crank bearing Crank pin Semi round key Crank left Connecting rod Balancer Balancer bearing Roller bearing of end side 4 43 ...

Page 113: ...rank assembly 90890 01275 Template pipe joint 90890 01378 Assembling and adjustment of engine ENG Note Keep the connecting rod on dead piont When mounting never contact crankcase Never use hammer to beat crank 2 Mount Balance axle aim the engraving mark a of driving gear of crank at engraving mark b balance axle gear then mount them 4 44 ...

Page 114: ... 17 18 Main axle Circlip Bearing Driving chain wheel Oil seal Bearing Driving gear 5gear Driving axle Driving gear Driving gear Driving gear Driving gear Bearing 2 3 4 1 11 12 13 14 15 Bearing Drive gear 5gear Drive gear 2gear Drive gear 3gear Drive gear 4gear 4 45 ...

Page 115: ...Assembling and adjustment of engine ENG Shiftcam shifting yoke Guide rod of shifoing yoke long 1 Shifting yoke 3 Shifting yoke 1 Cam Star shape gear Guide rod 2 of shifing yoke short 4 46 ...

Page 116: ...ng the push rod in the clutch into the inner hole of main sh aft then installing it 4 Installation O ring Garket O ring Drive shaft Install the O ring into the installing groove of firm bracket of sprocket of drive shaft avoid damage of oil sealing lip after installing the drive shaft take out the 4 47 3 Inspection Installing width of main shaft gear a Standard installing width of main width 82 25...

Page 117: ... the neutral switch of crankcase L The surface signed L is toward clutch Change cam tch Change fork C The surface signed with C is toward clutch Change fork guide rod Change fork guide rod 6 Inspection Operation of change cam The operation of change cam The operation is unsmooth reinstall Turn the change cam cam with hand to make sure that the driving and fork is smooth in operation Note 4 48 ...

Page 118: ...Fastening order 1 2 3 4 5 Left crankcase Dowel pin Airflow pipe Right crankcase Clutch fastening clip Assembling and adjustment of engine ENG Yamaha bonder No 1215 4 49 ...

Page 119: ...tion Action of crankshaft and transmission The action is not smooth repair 5 Fastening Screw crank case Seal gum Yamaha bonder No 1215 90890 85505 Note Never allow any seal gum to enter into the lubricati on oil hole Note Before installing and fastening the fastening screws of cranrcase be sure to turn the shift cam with hand to check if the transmission functions normally Note From the screw mark...

Page 120: ...g and adjustment of engine ENG Shift shafl pedal spindle and pedal idle speed gear Shift shaft Retainer Reset spring Tortion spring Star wheel Start shaft assy 11 Circlip Washer Idler pulley Washer Circlip 4 51 ...

Page 121: ...ttention to install the pin hole on the star wheel and the pin hole a on the cam correctly 3 Installation Retainer Spring Bolt Retainer 1 0kgf m 10Nm Note The retainer and the shift start wheel should be eng aged each other 4 Installation Shift shaft Note When installing the shift shaft be sure to jam the tortion spring on the dowel pin 4 52 ...

Page 122: ...idle speed gear 1 Installation Drive shaft Hoop Spring N ote The projecting part should be installed on the a po sition of crankcase and the fastening of spring should be down only after it turns 1turn 2 Installation Circlip Washer Idler pulley Washer Circlip 4 53 ...

Page 123: ...ring Press plate Clutch hub Retaining washer Main driven gear Steel ball Push rod Push rod assy 11 12 13 14 15 16 17 18 Drive gear Oil filter Dowel pin Drive gear of oil pump Drive gear of oil pump Oil pump case Clutch oil pump Assembling and adjustment of engine ENG 4 54 ...

Page 124: ...gear of oil pump Centrifugal filter Note Install the dowel pin a of centrifugal filter into the retainning groove of crankshaft b Main drive gear 1 Installation Main drive gear Dowel pin Washer Nut Note When locking the nut in order to avoid the rotation of crankcase the rotor must be fixed No articles such as alumium sheet cloth strip of copper sheet between gears They prevents the crankshaft fro...

Page 125: ...ock the nut and bend the retaining gasket Clutch fixtrue 90890 04086 Nut torque 60N m 6 0kgf 3 pieces Installation Friction linertotal of 4 Clutch plate total of 3 pieces Note Apply the engine oil of 4 stroke engine on each plate of clutch then install it Install the clutch plate and friction liner alternatively to the clutch hub starting from friction liner and ending with friction liner 4 56 ...

Page 126: ...ine ENG 4 Installation Steel ball 5 Installation Push rod 1 Push plate Washer Nut 6 Installation te Press pla Spring Screw Screw installing torque 0 6 kgf m 6 N m Note Tighten up the bolts orderly according to the diago nal order 4 57 ...

Page 127: ...ing lock the nut Adjustment Aligning identification of push rod 3 and crankcase Unlock the nut turn the push rod counter clockwise to the end Turn the push rod 1 left and right until a aligns with b 9 Installation Paper gasket new product Left crankcase cover 10 Installation Kick start rod Nut fastening torque 0 8kgf m 8 N m Crankcase cover installing torque 1 0kgf m 10N m Installing torque of kic...

Page 128: ...hain Guide plate of chain Locating shaft Idle start gear Press plate Washer Starting gear 2 11 12 Woodruff key Rotor Stator Paper gasket Dowel pin 13Left crankcase cover 4 59 Assembling and adjustment of engine ENG ...

Page 129: ...d When turn the starter gear counter clockwise B the clutch gear of starter should turn freely Othewise it ndicatesthat there is some throuble with starter clutch and it should be replaced Inspection procedures i Assembling and adjustment of engine ENG Installation Timing chain Chain guide plate Installation Starting the idler pulley Pressure plate 1 2 Installing torque 1 0Kgf m 10N m The guide pl...

Page 130: ...ening torque 7 0Kgf m 70N m Note Fasten the rotor with slide retaining tool lock the rotor with a nut with washer Slide retaining tool 90890 01701 7 Installation Dowel pin Paper gasket new product Left crankcase cover Fastening torque of crankcase cover 1 0Kgf m 10N m Note The left crankcase can be installed only after the lo cking nut of main drive gear of right crankcase has been installed 4 61 ...

Page 131: ... turn smoothly between each other There should be a 120 angle difference for the interfaces between the rings the splits of upper and lower oil scraping plate of oil ring should stragger about 20mm on the left and right sides of oily plate split The arrow mark a on the piston should be tow ard the front side of engine Before installing the piston pin hoop cover the cra nkcase with clean towel or c...

Page 132: ...Assembling and adjustment of engine ENG Cylinder and piston Cylinder O ring Paper pad Dowel pin Piston ring Piston pin hoop Piston Piston pin 4 63 ...

Page 133: ... adjustment of engine ENG Cylinder head Bolt Copper washer Inner hexagonal bolt Valve cover Intake O ring Valve cover Exhaust Cylinder head Dowel pin Steel pad O ring Side cover of cylinder head Spark plug 11 12 4 64 ...

Page 134: ...Assembling and adjustment of engine ENG Paper pad Tensioner Chain guide plate intake Timing sprocket Timing chain Chain guide plate exhaust Cam shaft and locating key 4 65 ...

Page 135: ...Chapter 5 Disassembling of carburetor General drawing of carburetor Removal of carburetor Adjustment of fuel level 5 1 5 2 5 5 ...

Page 136: ...Carburetor Spring Washer Rubber pad Idle speed adjusting screw 19 20 21 22 23 24 25 26 27 Start spanner Wave washer Screw Rubber cap Guide seat Starting pluger Spring plate Firm plate O ring 28 29 30 31 32 33 34 35 36 Rubber pad Washer Spring Ps adjusting screw Idling fuel Needle valve jet Main jet O ring Needle valve seat 37 38 39 40 41 42 43 44 45 Needle valve Firm clip Bolt Float Float pin Gask...

Page 137: ...CARB 5 Carburetor 1 Removal Throttle cable Caburetor Disassembly 1 Loosen Oil drain screw 2 Removal Plunger 3 Removal Starting wrench Starting plunger 4 Removal Float chamer 5 2 ...

Page 138: ...l Float pin Float Needle valve Needle valve seat 6 Removal Main jet Needle valve jet O ring 7 Removal Idling fuel jet 8 Removal P S adjusting screw Inspection 1 Inspection Mixing chamber case of carburetor If polluted clean 5 3 ...

Page 139: ...edle valve Needle valve seat O ring If worn or damaged replace Note The needle valve and its needle valve seat should be replaced as a complete set 5 Inspection Main nozzle 1 2 3 4 Main jet O ring Idling fuel jet If polluted clean Note Blow the jets with compressed air 5 4 ...

Page 140: ...e specification value adjust Measurement and adjustment procedures of fuel level Rest the motorcycle on the flat ground and make sure that the carburetor is in vertical condition Connect the fuel level dipstick with oil drain pipe 5 5 Fuel level a 6 6 7 6 mm The fuel level should be at the middle postion of the float chamber on the lower side of the carburetor case edge Fule level dipstick 90890 0...

Page 141: ...ber Measure the fuel level with fuel level dipstick Note The records of the fuel level dipsiticks of the pipes on two sides of the carburetor should be equal If the fuel level is not correct adjust it Remove the carburetor Check the valve seat and needle valve If they are all in good condition adjust the fuel level by bending the rear part of the float slightly Install the carburetor Check fuel le...

Page 142: ...n of clutch hub Installation of drive chain Removal of front fork Inspection of front fork Front fork assembly Steering shaft and handle Removal of handle Inspection of handle Inspection of front steering shaft Install ing of steering shaft Installation of handle bar Rear shock absorbor and rear arm Removal Inspection Front fork 6 1 6 1 6 4 6 5 6 6 6 9 6 10 6 13 6 15 6 15 6 17 6 17 6 18 6 19 6 22 ...

Page 143: ... ў Ъ M e t e r g e a r a s s y ў Ы F r o n t w h e e l a x l e ў Ь B u s h i n g ў Э F r o n t b r a k e a s s y ў Ю B u s h i n g ў Я F r o n t w h e e l 1 2 3 4 5 6 7 4 5 5 K g f m 4 5 5 N m 6 1 6 F r o n t w h e e l ў Щ S e l f l o c k i n g n u t ў Ъ M e t e r g e a r a s s y ў Ы F r o n t w h e e l a x l e ў Ь B u s h i n g ў Э F r o n t b r a k e a s s y ў Ю B u s h i n g ў Я F r o n t w h e...

Page 144: ... of front and rear wheels Front wheel Brake pad Washer Meter clutch Meter drive gear Brake arm Indicator Cam axle Bushing Washer Meter driven gear O ring Oil seal 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 0Kgf m 10 N m 6 6 2 ...

Page 145: ...nd 2 Place the motorcycle on its central stand 3 Place the proper articles under the frame or eng ine to lift the front wheel 2 1 2 1 Front brake 1 emoval Front brake cable R Note Before taking out the cable release the brake Note The clip should be taken out first 3 Removal Self Locking nut 6 3 ...

Page 146: ...e Never attempt to straighten the bent front wheel axle The twist limit of front axle 0 25mm 2 Inspection Wheel If deformed damaged of bent replace Never attempt to repair the wheel by yourself even the small repair 3 Inspection and fastening of spoke 1 2 Inspection Spoke If bent and damaged change If the spoke is slack tighten up Fastening Spoke Note After repairing be sure to adjust the slacknes...

Page 147: ...m Axial 0 5mm 5 windage unsmooth Inspection Wheel bearing If the bearing inside the hub has rotation slackness abnormal sound replace Oil seal If worn or damaged replace Speedometer gear assy 1 Removal Cable head of speedometer Driven chain of meter The speedometer cable should be free from bending Meter clutch 1 Inspection Meter clutch If deformed damaged replace 6 5 ...

Page 148: ...the grainsof polishing material 2 O Measurement Friction liner thickness of brake pad ut of specification replace The friction liner thickness of brake a Thickness a 4mm Limit 2mm Note If any brake pad is found to be worn to the wear limit replace the complete sets of brake shoes 3 Measurement Inner diameter of brake drum a Out of specification replace Inner diameter of brake drum Stardard value 1...

Page 149: ...oth 5 Inspection Cam axle Damaged replace When installing the cam axle and the central shaft apply a small amount of lubrication grease and clean off the surplus lubrication grease 1 y Installation Cam axle Indicator Let the convex part on the indicator a pass throughthe concave groove on the cam axle b and install it well Align the indicating needle with wear indicator Assembl Procedures of insta...

Page 150: ...pring Never apply the ludrication grease onthe friction liner of brake pad 4 t Installation Driven gear of meer Installing meter cable Speedometer cable head 5 Installation Brake assy Note The convex part on the inner side of the gear assy should be engaged with various surfaces each other the concex part of hub a should be jammed into the clutch b 6 8 ...

Page 151: ... axle 1 Installation Front wheel 2 Note The convex seat on the front fork should be engaged with the locating slot of the brake padplate correctly Cable The action of brake If the action is not smooth repair 3 pad 3 5 5 6kgfm 35 56N m Nut torsgue Installation Meter cable Clip When installing the meter cable don t bend it 4 6 9 ...

Page 152: ... Driven chain gear Pin Rear wheel Spring Rear brake assy plit pin Shock absorber Tension rod Oil seal Self locking nut Bushing Chain adjuster assy Bearing Rear wheel Inspection of front and rear wheels 11 12 14 13 NEW 6 10 ...

Page 153: ...CHAS Inspection of front and rear wheels Rear wheel Brake shoe Brake arm Indicator Cam axle 6 11 ...

Page 154: ...r o n t w h e e l a x l e ў Ь B u s h i n g ў Э F r o n t b r a k e a s s y ў Ю B u s h i n g ў Я F r o n t w h e e l 2 Removal Adjusting nut Tension rod Nut Spring Brake pull rod Rear wheel nut 6 3 Removal Rear wheel axle bushing Note When removing the rear wheel axle the bushing will fall down Be careful not to lose it 4 Removal Rear wheel Rear brake Note When removing the rear wheel axle the cl...

Page 155: ...ction Inner surface of brake drum Oil stain or scrape repair Oil stain Wipe a cloth dipped in the paint diluent or solvent Scrape Poslish slightly and evenly with a emery cloth Brake hub inner diameter Standard value 130mm Limit value 131mm 2 Measurement Brake hub inner diameter a Out of specification replace 6 13 ...

Page 156: ...ock block 4 Installation Rear wheel axle 1 2 3 4 5 6 7 4 5 5 K g f m 4 5 5 N m 6 1 6 F r o n t w h e e l ў Щ S e l f l o c k i n g n u t ў Ъ M e t e r g e a r a s s y ў Ы F r o n t w h e e l a x l e ў Ь B u s h i n g ў Э F r o n t b r a k e a s s y ў Ю B u s h i n g ў Я F r o n t w h e e l Fastening rorque of rear wheel axle 9 1 Kgf m 91 N m 6 14 ...

Page 157: ...S Drive chain and sprocket Rear drive chain Small sprocket drive Chain press plate Connector of chain Chain drive chain Big sprocket driven Adjuster assy Circlip Retaining press plate Sprocket cover1 6 15 ...

Page 158: ...l Sprocket cover 3 Removal Drive sprocket 4 Removal Chain joint clip Press plate of chain Chain Driven chain Inspection of drive chain 1 Inspection Drive chain jam If jammed Lubricate after cleaning or replace 2 1 2 Inspection Drive chain Drive chain As shown on the fig the clearance after extruding right cannot exceed gear If out replace 6 16 ...

Page 159: ...r side of the roller Measure the length of 10 links at diffrient parts for 2 3 times 11 5 Cleaning Clean with neutral detergent After cleaning apply a plenty of chain lubrication oil of SAE10 w 30w YAMAHA 4 stroke engine oil Warning Never clean with the volatile matters such as steam gasoline solvent etc Inspection of clutch hub 1 Inspection Clutch hub If worn damaged cracked replace 1 Installatio...

Page 160: ...nstallation of drive chain 2 Installation Chain joint clip Note As shown on the fig pay attention to the installing direction of chain joint clip 3 3 Adjustement The slackness of drive chain Refer to the section Adjustment of drive chain slack ness of chapter Note If the slackness of drive chain is too small it will cause the engine and other main components to overload The chain slackness should ...

Page 161: ...nt fork CHAS Bolt 11 Washer 12 Plug rod of oil stocking 13 Damper rod 14 Inner pipe 15 Spring 16 Oil seal 17 Outer Front fender Plug Bolt O ring Spacer Spring seat Spring Dust cover Clip pipe NEW NEW 6 19 ...

Page 162: ...e a proper bracket under the frame and the engine to surpport the front wheel 2 Removal Front wheel Front fender 3 Loosen Loosen the bolt Cover bolt 4 Note When removing the front fork remove the 2 bolts for fastening the front fork Removal of front fork Removal Cover bolt and O ring 1 Oil drain 2 Removal Spacer Spring seat Spring 3 6 20 ...

Page 163: ...od loosen the bolt with T and shock absorber fixture 6 Removal Bolt Washer Oil seal Note Note Be careful not to damage the surface of inner pipe T flat handle 90890 01294 When removing the oil seal be careful not to scrape the pipe wall of outer fork lever 6 21 Front fork CHAS ...

Page 164: ...Free length of front fork spring a Free length of front fork spring 336 9mm Min free play 330mm Out of specification replace 3 Inspection Damper rod Shock aborbor piston Scraped damaged bent replace Spring Plug rod of oil stocking Worn damaegd replace Pollutant blow off all oil holes with compressed air Note Never attempt to straighten the bending damper rod otherwise the damper rod will be damage...

Page 165: ...nt fork use the follow ing new components Oil seal Dust cover Before reassembling make sure that all compon ents are cleaning 1 Installation Spring Shock absorber piston 2 Lubrication Inner pipe Outer surface Shock absorbor oil 10W or equal 3 Installation Shock absorber rod Plug rod of oil stocking Inner pipe Outer pipe 4 Installation Washer Bolt shock absorber rod 6 23 ...

Page 166: ...lt damper rod Bolt 2 3Kgf m 23N m Fasten the bolt of damper rod with T handle wr ench and damper rod fixture Note T tool 90890 01326 Shock absorber rod fixture 90890 01294 6 Installation Oil seal 7 Installation Clip Outer pipe 6 24 ...

Page 167: ... absorber oil 10 After filling oil move the front fork up and down slo wly so as to let the oil spread into the pipe 11 Installation Spring When installing let the end of front fork spring with small play to toward the cover bolt side Install the O ring on the cover bolt Note 12 Installation Cover bolt O ring Be careful not to damage the surface of inner pipe Note 6 25 ...

Page 168: ...dures of removal 1 Installation Front fork Tighten up the fixing bolt tempotarily Note When installing align the inner pipe end with bolt head end 2 Fastening Bolt Bolt Cover bolt Torque of position 2 8Kgf m 28N m Torque of pisition Kgf m 23N m Cover bolt torque 2 3Kgf m 23N m 6 26 ...

Page 169: ...assy Handle bar seat Limit clip Ring nut Ring rubber pad Ring nut Dust cover Steering axle Bearing race upper Roller holding bracket upper Roller holding bracket lower Bearing race2 middle Bearing race Lower 11 12 13 14 15 The inner diameter of two bearing races are different 6 27 ...

Page 170: ...Steering axle and handle bar CHAS Handle bar 1 Removal Remove left and right lever switches 2 Removal Handle bar holder Handle bar Handle bar seat Removal Front wheel 3 4 Removal Front fork 6 28 ...

Page 171: ...ning Remove only with wrench 7 Removal Bearing race 2 Roller race 2 Roller Steering axle Roller holding bracket Lower holding bracket upper 1 Inspection Handle bar If bent cracked damaged replace Inspection of handle bar Warning Do not attempt to straighten the bending handle bar otherwise it will decrease the operation function of the handle bar causing danger 6 29 ...

Page 172: ...s roller holding bracket and bearing race The roller holding bracket bearing race and dust seal parts are always replaced as a complete set If the roller holding bracket and bearing race are installed at a slant the frame will be worn so install them in horizontal condition Never beat the roller and rod surface Installation of steering axle 1 2 3 Conduct installation according to the reverse proce...

Page 173: ...3N m Note The bolt ahead must be fastened first When assembling the steering the projection of handle bar clamp is in front of installation direction 2 Install Front brake lever Clutch lever 3 Install Lever switch When installing locating pin a of the lever switch sh ould be inserted into the locating hole b of the handle bar 6 31 ...

Page 174: ...CHAS Rear shock absorber and rear arm Rear shock absorber Nut Rear rocker arm Connecting rod Chain shield 6 32 ...

Page 175: ...k absorber 3 Remove Rear wheel 4 Remove Chain 5 Remove Nut Connecting rod Chain shield Rear rocker arm Inspection 1 Check Slackeness of rocker arm If it is loose screw up the axle nut or replace bush Vertical movement of rocker arm If it is unflexible bend and there is rough part replace the bush 2 Check Rear shock absorber If it is leak deformation replace it 6 33 ...

Page 176: ... drawing of circuit Electric components Inspection of socket connector Inspection of switch Ignition system Starting system Starting motor Charge system Lighting system Signal system 7 1 7 3 7 5 7 6 7 8 7 12 7 17 7 22 7 26 7 31 ...

Page 177: ...Circuit ELEC Circuit Drawing 7 7 1 ...

Page 178: ... 24 25 26 27 B Br Dg G L Or Sb P R Y W B W B R Br W G W G Y W L W R B Y L W L B R W Black Brown Russet Deep green Green Blue Orange Sky blue Pink Red Yellow White Black White Black Red Brown White Green White Green Yellow White Blue White Red Black Yellow Blue White Blue Black Red White 11 12 13 Magneto Rectified adjuster Battery Starting relay Starting motor Positive wire Negative wire Main switc...

Page 179: ...Circuit ELEC Electric components 5 6 7 8 Rectifying adjuster Fuel sensor Three keys assy Main cable 1 2 3 4 Battery Rear brake switch Starting relay Fuse plate 7 3 ...

Page 180: ...Circuit ELEC Electric components 4 Flash relay assy 1 2 3 Ignition coil assy Spark plug cap assy Neutral switch assy 5 CDI unit 6 Horn 7 4 ...

Page 181: ...nd post is pulled out by hand bend he pin and insert the binding post into the socket co nnector again If the 6 7 Connect Socket connector Check if the circuit is conducted with multitester I binding post Note f the non conduction of circuit is found clear every When checking the bale of wire the procedure of inspection must be done according to above 1 7 steps When replacing the CDI every socket ...

Page 182: ...ery switch should be done by Ω 1 Every switch terminal in the manual Inner connecting terminal abbreviated drawing of switch such as main switch handlebar switch brake switch an lighting switch etc see left figure often appear in this manual The switch position is recorded in the left column of terminal connection table which the wire color connec ting terminal is written down at the upper column ...

Page 183: ...Ignition System ELEC Circuit of ignition system Maganeto CDI unit Ignition coil spark plug Main switch 11 12 8 4 7 7 ...

Page 184: ...cluding Ignition tester 90890 06754 Min multitester 90890 03112 Spark plug type CR6HSA Spark plug clearance 0 6 0 7mm Spark plug cap High pressure coil voltage gauge Voltage gauge wire of high pressure coil Spark plug 2 Inspection of the spark Turn the main switch to ON for checking if the spark gets to the normal value above When pressing the starting switch check if the spark a gets to normal va...

Page 185: ...k plug cap check the high pressure wire first Cut off the front end of high pressure wire about 5mm before installing Resistance value of ignition coil primary 0 3Ω 10 20 C Remove the high pressure coil ignition coil Connect the multitester test frequencyΩ 1 to the terminal of ignition coil lead wire of voltage gauge spark plug side lead wire of voltage gauge high pressure wire side out of specifi...

Page 186: ...dapter of the pulse coil with wire Connect the multitester testΩ 1000 to the adapter of pulse coil for measure of coil resistance lead wire of voltage gauge Red terminal lead wire of voltage gauge White terminal Replace the pulse coil Out of normal value The ignition coil is failure replace it Abnormal lead wire of voltage gauge High pressure wire lead wire of voltage gauge Orange terminal Resista...

Page 187: ...of charge coil Ω 1000 Connecting method Resistance of charge coil 860Ω 20 20 C Normal Out of normal value Replace the ignition charge coil Lead wire of voltage gauge Green terminal lead wire of voltage gauge Brown terminal Change CDI unit assy 7 Wire joint Refer to the loop connection of ignition system Normal Poor connection Correct or replace 7 11 ...

Page 188: ...Starting system ELEC Circuit of starting system Battery Starting relay Starting motor Main switch Right lever switch Clutch switch 21Neutral switch 7 12 ...

Page 189: ...on The following specific tool should be used when excluding Min multitester 90890 03112 Remark 1 Fuse Remove fuse Connect min multitester Ω 1 to the fuse Check if the fuse is conducted 2 Battery 12 5V 1 280 at 20 C 68 F Check the battery condition Refer to the third chapter Battery Voltage Electrolyte specific gravity Supplement the electrolyte Clear the binding post of battery Charge or replace ...

Page 190: ... If the starting motor is failure replace it Connect the positive binding post of battery to the cable of starting motor with cross bond See figare Remove the adapter of starting relay from the bundle conductor Connect the battery to the wire of starting relay with cross bond See figure Check if the starting motor work If the starting motor is failure replace it Out of work Out of work Work Work W...

Page 191: ...f the switch is conducted between the sky blue wire and the ground wire Normal Abnormal If the main switch is failure replace it Normal If the neutral switch is failure replace it Abnormal Remove the branch connetor of main switch from the bale of wire Check if the switch is conducted between the red and the brown 7 15 ...

Page 192: ...ector of clutch switch from the bale of wire Check if the clutch switch is conducted between the black and the black If the clutch switch is failure replace it Normal R 8 Wire joint Poor connection break Correct or replace Refer to the loop wire of starting system 7 16 ...

Page 193: ... ring Magnet wheel Electric button Adjusting pad Front bracket O ring Length limit value of electric brush 3 5mm 7 17 A B C D 0 017 0 021Ω20 C Resistance value of electric button coil Hexagon slot m 1 5m Wear limit value of commutator 21 0mm Starting motor Starting system ELEC ...

Page 194: ...ntifiable mark on the frond and rear bracke to be easy to check when asse mbling The front bracket pad The rear bracket Remove Electric button Magnet wheel Electric brush Commutator Dirt on the comutator polish it with Measure Diameter of the commutator a Out of normal value Repace the starting motor 7 18 Wear limit value of commutator 21mm Starting system ELEC ...

Page 195: ...r Connect min multitester for the test of conduction and insulatiom Measure the resistance value of the electric button 5 If the resistance value is abnormal replace the starting mot Measure Electric brush length a Out of normal value Replace the electric brush as a se Inspection procedure Resistance value of electric button coil Conduction test 0 017 0 021Ω at 20 C 68 F Insulation test more than ...

Page 196: ...va Assemble Note When assembling the electric brush the electric brush wire should wrap the outer side of proje ction of electric brush spring clamp When assembling the eclectric brush the binding post of electric brush wire should slightly touch the projection lying in the side of electric brush spring clamp 2 Install Electric button Note When installing the electric button press down the electri...

Page 197: ... installation is done Note 5 Install Pad Front bracket The installation is done after the project of washer is align with the groove of front bracket Make the matching mark on the magnetic yoke be align with that of front rear bracket Note Bolt 0 5Kgf m 5N m 1 Install The starting motor Installation 2 Install The starting motor Wire of starting motor Botl 0 7Kgf m 7N m 7 21 ...

Page 198: ...Charge system ELEC Charge system Circuit Diagram CDI magneto Rectifing adjustor Battery Starting relay 7 22 ...

Page 199: ...removed Side cover Cushion The following specific tool should be applied Multitester 90890 03112 Check if the fuse is conducted Replace the fuse 1 Fuse No conduction Conduction 2 Battery Abnormal Supplement the electrolyte distilled wate Clear the binding post of battery Charge or replace the battery Check the battery condition Voltage Specific gravity of electrolyte 12 5V 1 280at 20 C 68 F Normal...

Page 200: ...ge 14 0V at 5000r min Remark Battery charged fully should be applied The charge circuit is normal Normal value Out of normal value 4 Resistance value of charge coil Remove the branch connector of charge coil from bundle conductor Connect the min Multitester Ω 1 to the charge coil Measure the resistance value of charge coil Positive wire of multitester White wire Negative wire of multitester White ...

Page 201: ...harge system ELEC 5 Connecting condition of wire Check the whole connecting condition of charge system Refer to section circuit Diagram Normal Reinstall the rectifier adjuster Poor connetion Correct 7 25 ...

Page 202: ...Lighting system ELEC Lighting system Circuit diagram Battery Right lever switch 22 23 Head lamp Tail lamp 7 26 ...

Page 203: ...the bulb and socket are conducted 2 Fuse 3 Battery If the bulb or socket is failure replace it Supplement eletrolyte distilled water Clear the binding post of battery Charge or replace the battery If the fuse is broken replace it Remove the fuse Connect the min multitester to the fuse Check if the fuse is conducted Refer to Inspection of fuse section of the 3 chapter Ω 1 Check the battery conditio...

Page 204: ... the red and the brown is conducted Remove the branch connector of handle bar sw itch right from the bundle conductor Connect min Multitester Ω 1 to the binding post of handle bar switch right Check if the switch between the brown and the blue black is conducted Remove the branch connector of handle bar switch left from the bundle conductor Connect min Multitester Ω 1 to the binding post of handle...

Page 205: ...immer switch of headlamp to HI or LO Check if the voltage of socket connector between the green and the yellow wire gets to 12V Meet normal valur 12V This circuit is normal Poor lagout from main switch to the socket The repair is needed 1 Bulb and socket Connect Min multitester DC20V to branch connector of headlamp and to that of indicator When the dimmer switch of headlamp lies in lower beam pois...

Page 206: ...b and socket 2 Voltage Positive wire of multitester blue binding post Negative wire of multitester black binding post Turn the main switch to ON position Turn the garde light switch to ON position Check if the voltage of blue wire on socket Meet normal value 12V If layout from the main switch to the socket connector is poor repair it No conduction Replace the bulb or the socket If the layout from ...

Page 207: ... relay Battery Front brake switch Rear brake switch Horn Left handle lever switch assy 19 Flash relay 20 16 17 18 23 2426 25 27 21 Tai lamp brake lamp Front left right turning lamp Rear left right turning lamp Fuel signal sender Instrument assy Neutral switch 15 14 7 31 ...

Page 208: ...nection condition of guide wire Check every circuit condition signal system Refer to Inspection of signal system section Poor conduction Replace the fuse Supplement electrolyte distilled water Clear the binding post of battery Charge of replace battery The main switch is failre replace it The correct should be done Voltage Special gravity of electrolyte 12 5V 1 280 20 C Check the socket connector ...

Page 209: ...ts to 12V Connect the min multitester DC20V to Pink binding post of horn Positive guide wire of multitester Pink guide wire Negative guide wire of multitester Frame ground Turn the main switch to ON Check if the Pink guide wire voltage at the binding post of horn gets to 12V No function of the horn Adjust or replace horn The horn switch is failure the lever switch left should be replaced Out of no...

Page 210: ...o socket connector Positive guide wire of multitester Yellow guide wire Negative guide wire of multitester Black guide wire Turn the main switch to ON Pull brake lever or step brake pedal Check if the voltage of Yellow guide wire at the socket connector gets to 12V Meet normal value The circuit is normal If the brake switch is failure replace it Out of normal value There is poor layout from the ma...

Page 211: ...linker relay Guide wire Brown white terminal guide wire Body ground Turn the main switch to ON Turn the blinker to left or right Measure the voltage of brown white guide wire 12V Replace the bulb or the socket The turn signal switch is failure replace the handlebar switch left There is poor layout from the main swotch to the relay binding post of blinker device the repair is needed Replace the bli...

Page 212: ...ge of brown guide wire of dark geeen guide wire at socket connector gets to Meet normal value Layout of signal loop is normal Out of normal value 6 Circuit joint Check if there is break at connection part of loop of signal system Refer to connection diagram of loop of signal system 4 Neutral indicator no work 1 Bulb and socket Check if the bulb and the socket are conducted Conduction 2 Neutral swi...

Page 213: ...Signal system ELEC 7 37 ...

Page 214: ...3 Fuel gauge Turn the main switch to ON Move the float to Max upper postion or max Lower position to check the fuel gallge needle s action Normal The loop connection of signal system is normal Remark Firm the float bowl on the 1 or 2 position respectively for over 3 minutes to confirm the needle of fuel gauge Poor function Replace petrol gauge Connect fuel level sensor to circuit joint Move the fl...

Page 215: ......

Page 216: ...arge coil refer to page 7 7 7 22 7 7 22 Damage of winding Check all socket connector of guide wire Starter motor rdfer to page 7 14 Damage or failure of starter motor Failure of starter relay Failure of starter cultch Failure breaking relay Damage of short circuit of main coil or secondary coil Failure of high pressure guide wire Failure of spark plug cap Apparent carbon deposit Moisture of electr...

Page 217: ...le Compressure system Buckle carbon deposit Inadequate tight force Damage Carbon deposit Buckle wear damage Wear scratch damage Wear choke damage Wear scratch Wear choke damage Damage Wear choke damage Damage Damage Damage Damage 8 2 ...

Page 218: ...Troubleshooting of engine Trouble Intake and exhaust system 8 3 ...

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Yamaha YBR125 Custom, Service Manual

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