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NOTE:

WARNING

CAUTION:

EB001000

NOTICE

This manual was produced by the Yamaha Motor Company primarily for use by Yamaha dealers and
their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual,
so it is assumed that anyone who uses this book to perform maintenance and repairs on Yamaha
motorcycle has a basic understanding of the mechanical ideas and the procedures of motorcycle
repair. Repairs attempted by anyone without this knowledge are likely to render the motorcycle unsafe
and unfit for use.

Yamaha Motor Company, Ltd. is continually striving to improve all its models. Modifications and
significant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers
and will appear in future editions of this manual where applicable.

Designs and specifications are subject to change without notice.

EAS00004

IMPORTANT INFORMATION

Particularly important information is distinguished in this manual by the following notations.

The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR
SAFETY IS INVOLVED!

Failure to follow WARNING instructions could result in severe injury or death to
the motorcycle operator, a bystander or a person inspecting or repairing the
motorcycle.

A CAUTION indicates special precautions that must be taken to avoid damage
to the motorcycle.

NOTE:

A NOTE provides key information to make procedures easier or clearer.

Summary of Contents for 2002 TW125

Page 1: ......

Page 2: ...on procedures it is necessary to use this Supplementary Service Manual together with the following manual TW125 SERVICE MANUAL 5EK1 AE1 TW125 2002 SUPPLEMENTARY SERVICE MANUAL E2001 by Yamaha Motor Co Ltd First Edition August 2001 Any reproduction or unauthorized use without the written permission of Yamaha Motor Co Ltd is expressly prohibited ...

Page 3: ...l its models Modifications and significant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers and will appear in future editions of this manual where applicable Designs and specifications are subject to change without notice EAS00004 IMPORTANT INFORMATION Particularly important information is distinguished in this manual by the following notations The Safety...

Page 4: ...pections and Adjustments where the sub section title s appear In Chapter 3 Periodic Inspections and Adjustments the sub section title appears at the top of each page instead of the section title 3 Sub section titles appear in smaller print than the section title 4 To help identify parts and clarify procedure steps there are exploded diagrams at the start of each removal and disassembly section 5 N...

Page 5: ... Troubleshooting Symbols 9 to 16 indicate the following 9 Serviceable with engine mounted 10 Filling fluid 11 Lubricant 12 Special tool 13 Tightening torque 14 Wear limit clearance 15 Engine speed 16 Electrical data Symbols 17 to 22 in the exploded diagrams indi cate the types of lubricants and lubrication points 17 Engine oil 18 Gear oil 19 Molybdenum disulfide oil 20 Wheel bearing grease 21 Lith...

Page 6: ...RGING THE BATTERY 21 REPLACING THE HEADLIGHT BULB 27 ADJUSTING THE HEADLIGHT BEAM 28 ENGINE CLUTCH 29 CARBURETOR CARBURETOR 31 CHECKING THE CARBURETOR 34 ASSEMBLING THE CARBURETOR 36 INSTALLING THE CARBURETOR 37 MEASURING AND ADJUSTING THE FUEL LEVEL 37 CHASSIS FRONT WHEEL AHD BRAKE DISC 39 REAR WHEEL AND REAR BRAKE 40 REAR WHEEL 40 REAR BRAKE AND REAR WHEEL SPROCKET 42 FRONT FORK 44 HANDLEBAR 45 ...

Page 7: ...smission Primary reduction system Primary reduction ratio Secondary reduction system Secondary reduction ratio Transmission type Operation Gear ratio 1st 2nd 3rd 4th 5th Spur gear 74 20 3 700 Chain drive 51 14 3 643 Constant mesh 5 speed Left foot operation 36 16 2 250 31 21 1 476 27 24 1 125 25 27 0 926 23 29 0 793 Chassis Frame type Caster angle Trail Diamond 25_50 93 mm Tire Type Size front rea...

Page 8: ... Battery type Battery capacity C D I A C magneto GT6B 3 12 V 6 AH Bulb wattage quantity Headlight Auxiliary light Tail brake light Turn signal light Meter light High beam indicator light Neutral indicator light Turn signal indicator light 12 V 60 W 55 W 1 12 V 4 W 1 12 V 5 W 21 W 1 12 V 21 W 4 12 V 3 4 W 1 12 V 3 4 W 1 12 V 3 4 W 1 12 V 3 4 W 1 2 ...

Page 9: ...w P S Valve seat size V S Starter jet 1 G S 1 Starter jet 2 G S 2 Fuel level F L Engine idle speed Intake vacuum MV28 5RS1 00 134 ø1 2 5A50 3 5 B1 60 90 120 0 8 34 0 7 0 7 0 7 0 7 1 1 2 1 6 0 6 0 8 0 X 2 0 mm 1 450 X 1 650 r min 190 X 230 mmHg SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS SSS TIGHTENING TORQUES ENGINE Part to be tightened Part name Thread size Q ty Ti...

Page 10: ...SS SSS SSS SSS 0 2 mm Rear suspension Shock absorber stroke Spring free length Fitting length Spring rate K1 Stroke K1 48 mm 190 mm 185 mm 127 N mm 12 7 kg mm 0 X 48 mm SSS 171 mm SSS SSS SSS Drive chain Type manufacturer No of links Chain free play Maximum ten link section 428HD DAIDO 125 35 X 60 mm 129 5 mm SSS SSS SSS SSS Rear brake Type Drum inside diameter Shoe thickness Shoe spring free leng...

Page 11: ...haft moving smooth ly 2 First tighten the ring nut approximately 38 Nm 3 8 mSkg by using the torque wrench then loosen the ring nut one turn and retighten the ring nut to specification ELECTRICAL Item Standard Limit Charging system Type Model manufacturer Standard output Stator coil resistance color C D I magneto F5BT YAMAHA 14 V 170 W 5 000 r min 0 48 X 0 72 Ω at 20_C White White SSS SSS SSS SSS ...

Page 12: ...ch lead 5 Main switch lead 6 Clutch cable 7 Clutch switch lead 8 Speedometer cable 9 Left handlebar switch lead 10 Front turn signal light lead left 11 Meter lead A Clamp the grommet of brake hose with the band After completion of clamping cut the surplus part and point it to the backward B No positioning for the headlight body is specified C To the headlight CABLE ROUTING 6 ...

Page 13: ...Handlebar switch lead right and front brake light switch lead should not be twined around 1 Battery positive lead 2 Starter relay 3 Starter motor lead 4 Clamp 5 Ignition coil 6 Throttle cable pull side 7 Throttle cable return side 8 Throttle cable holder 9 Horn lead 10 Spark plug lead 11 Relay White 12 C D I unit CABLE ROUTING SPEC 13 Diode 14 Resister lead 15 Turn signal relay 7 ...

Page 14: ... starter cable F Clamp the ignition coil lead and the ignition coil grand lead horn lead G Route the wire harness handle bar switch lead right and front brake light switch lead through the guide H Do not bend the lead sharply just after the terminal connection D Clamp the wire harness handle bar switch lead right front brake light switch lead clutch switch lead and main switch lead After clamping ...

Page 15: ...the rear brake switch lead connector and turn signal relay lead with the band and point the surplus part to the inner side then cut it Secure the connector at the front part of frame M Push the wire harness in be tween frame and box N Place the C D I unit on the mounting port for the left side relay 9 ...

Page 16: ...ector is torn Do not pinch the resonator hose D Place the coupler below the res onator hose 1 Resonator hose 2 Fuel hose 3 Rectifier regulator lead 4 Thermo switch lead 5 Sidestand switch lead 6 Air filter case 7 Breather hose 8 Battery negative lead 9 C D I magneto leads 10 Over flow hose 11 Air vent hose 12 Clutch cable 13 Clutch cable guide 14 Brake hose 15 Speedometer cable 16 Handlebar switch...

Page 17: ...w hose starter motor lead and neutral switch lead J Hold down the side stand switch lead using the special washer K Route the air vent hose and over flow hose between engine and swingarm L Route the starter motor lead be E Clamp the rectifier regulator lead and resonator hose Point the surplus part toward the inner side Clamp within a range where the resonator hose pro tector is torn Do not pinch ...

Page 18: ...ange toward the traveling direc tion of vehicle Y Place the brake hose in the outer side R Clamp the brake hose and speedometer cable Align the clamping position with the center of white paint mark on the brake hose S Clamp the brake hose and speedometer cable with a hold er T Point the speedometer cable cap to the backward U Make sure to push in the boot ful ly 12 ...

Page 19: ...tarter motor lead 7 Battery positive lead 8 Wire harness 9 Clamp wire harness 10 Thermo switch lead 11 Sidestand switch lead 12 Negative lead 13 Battery negative lead 14 Grommet 15 Rectifier regulator 16 Clamp rectifier regulator lead 17 Handlebar switch lead left 18 Clutch switch lead 19 Clutch cable 20 Master cylinder 21 Starter cable 22 Rear turn signal light lead 23 Turn signal light stay 13 ...

Page 20: ...turn signal light lead right Point the surplus part to the inner side E Cover the naked part of rear turn signal light lead right with the hose F Cover the naked part of rear turn signal light lead left with the hose G Clamp the wire harness and rear turn signal lead right A Clamp the handlebar switch lead and front brake light switch lead with a band B Clamp the throttle cables C Clamp the C D I ...

Page 21: ...the rear K Clamp the thermo switch lead coupler After clamping point the surplus part to the inner side L Pass the C D I magneto lead 2 leads through the grommet side M Place the cover to the corner of rectifier regulator N No special order is set for the C D I magneto lead 2 leads neutral switch lead starter motor lead and battery negative lead 15 ...

Page 22: ... filter element S Replace 5 Clutch S Check operation S Adjust 6 Front brake S Check operation fluid level and vehicle for fluid leakage 6 Front brake S Replace brake pads Whenever worn to the limit 7 Rear brake S Check operation and adjust brake pedal free play 7 Rear brake S Replace brake shoes Whenever worn to the limit 8 Brake hose S Check for cracks or damage 8 Brake hose S Replace Every 4 yea...

Page 23: ...e for oil leakage 23 Engine oil filter element S Clean 24 Engine oil strainer S Clean 25 Front and rear brake switches S Check operation 26 Moving parts and cables S Lubricate 27 Lights signals and switches S Check operation S Adjust headlight beam D The air filter needs more frequent service if you are riding in unusually wet or dusty areas D Hydraulic brake service SRegularly check and if necess...

Page 24: ...d Out of specification Adjust Engine idling speed 1 450 X 1 650 r min 4 Adjust Sengine idling speed a Turn the pilot screw 1 in or out until it is light ly seated b Turn the pilot screw out the specified number of turns Pilot screw 1 1 2 turns out c Turn the throttle stop screw 2 in direction a or b until the specified engine idling speed is obtained Direction Engine idling speed is increased Dire...

Page 25: ...erator cable b Turn the adjusting nut 3 in direction a or b to take up any slack on the decelerator cable c Loosen the locknut 4 on the accelerator cable 1 d Turn the adjusting nut 5 in direction a or b until the specified throttle cable free play is obtained Direction Throttle cable free play is increased Direction Throttle cable free play is decreased e Tighten the locknuts If the specified thro...

Page 26: ...rottle cable free play is increased Direction Throttle cable free play is decreased d Tighten the locknut After adjusting the throttle cable free play turn the handlebars to the right and to the left to ensure that this does not cause the en gine idling speed to change 20 ...

Page 27: ...ctrolyte as it can cause severe burns or permanent eye injury First aid in case of bodily contact External SSKIN Wash with water SEYES Flush with water for 15 minutes and get immediate medical attention Internal SDrink large quantities of water or milk fol lowed with milk of magnesia beaten egg or vegetable oil Get immediate medical atten tion SThis is a sealed battery Never remove the sealing cap...

Page 28: ...ve Sseat 2 Disconnect Sbattery leads from the battery terminals First disconnect the negative lead 1 then the positive lead 2 3 Remove Sbattery 4 Check Sbattery charge a Connect a pocket tester to the battery termi nals Tester positive lead battery positive Tester positive lead terminal Tester negative lead battery negative Tester negative lead terminal SThe charge state of a MF battery can be che...

Page 29: ... with the battery mounted on the motorcycle disconnect the negative lead from the battery terminal STo reduce the chance of sparks do not plug in the battery charger until the battery charger leads are connected to the battery SBefore removing the battery charger lead clips from the battery terminals be sure to turn off the battery charger SMake sure that the battery charger lead clips are in full...

Page 30: ...n checking steps If the current does not exceed the standard charging current after 5 minutes replace the battery If charging requires more than 5 hours it is advisable to check the charging current after a lapse of 5 hours If there is any change in the amperage readjust the voltage to obtain the standard charging current Measure the battery open circuit voltage after leaving the battery unused fo...

Page 31: ...tery until the battery s charging voltage is 15 V This type of battery charger cannot charge the MF battery A variable voltage charger is recommended Measure the battery open circuit voltage after leaving the battery unused for more than 30 minutes 12 8 V or more Charging is complete 12 7 V or less Recharging is required Under 12 0 V Replace the battery Set the charging time at 20 hours maximum YE...

Page 32: ... Install Sbattery 8 Connect Sbattery leads to the battery terminals First connect the positive lead 1 then the negative lead 2 9 Check Sbattery terminals Dirt Clean with a wire brush Loose connection Connect properly 10 Lubricate Sbattery terminals Recommended lubricant Dielectric grease 11 Install Sseat 26 ...

Page 33: ... bulb until it has cooled down 4 Install Sheadlight bulb New Secure the new headlight bulb with the head light bulb holder Avoid touching the glass part of the head light bulb to keep it free from oil otherwise the transparency of the glass the life of the bulb and the luminous flux will be adversely affected If the headlight bulb gets soiled thoroughly clean it with a cloth moistened with alcohol...

Page 34: ...am vertically a Turn the adjusting screw 1 in direction a or b Direction Headlight beam is raised Direction Headlight beam is lowered 2 Adjust Sheadlight beam horizontally a Turn the adjusting knob 2 in direction a or b Direction Headlight beammoves to the right Direction Headlight beammoves to the left 28 ...

Page 35: ...lates Nut Lock washer Clutch boss Thrust washer Clutch housing Ball Long clutch push rod Push lever screw Gasket 4 1 5 4 1 1 1 1 1 1 1 1 1 Remove the parts in the order listed Refer to REMOVING INSTALLING THE CLUTCH section in chapter 4 Manual No 5EK1 AE1 8 Nm 0 8 mSkg 70 Nm 7 0 mSkg 12 Nm 1 2 mSkg 6 Nm 0 6 mSkg EAS00274 ENGINE CLUTCH 29 ...

Page 36: ...t clutch push rod O ring Push plate 1 1 1 1 1 1 1 1 1 Refer to INSTALLING THE CLUTCH section in chapter 4 Manual No 5EK1 AE1 Refer to INSTALLING THE CLUTCH section in chapter 4 Manual No 5EK1 AE1 For installation reverse the removal procedure 8 Nm 0 8 mSkg 70 Nm 7 0 mSkg 12 Nm 1 2 mSkg 6 Nm 0 6 mSkg CLUTCH ENG 30 ...

Page 37: ... screw Air filter joint clamp screw Carburetor assembly Throttle cables 1 1 1 2 Remove the parts in order listed SDisconnect the connector from carburetor SDisconnect the starter cable For installation reverse the removal procedure NOTE Refer to SEAT FUEL TANK AND SIDE COVER section in chapter 3 Manual No 5EK1 AE1 Loosen EAS00480 CARBURETOR CARBURETOR 31 ...

Page 38: ...lve spring Jet needle holder Jet needle spring Jet needle Piston valve Carburetor heater Adjusting screw Drain screw Float chamber Gasket 1 1 1 1 1 1 1 1 1 1 1 Disassemble the parts in the order listed Refer to ASSEMBLING THE CARBURETOR 1 2 3 4 5 6 7 8 9 10 11 CARBURETOR ENG EAS00483 32 ...

Page 39: ...edle valve seat Main jet Main jet holder Needle jet Pilot jet Pilot screw Rubber diaphragm spring Rubber diaphragm Starter plunger 1 1 1 1 1 1 1 1 1 1 1 1 For assembly reverse the disassembly procedure Refer to ASSEMBLING THE CARBURETOR 12 13 14 15 16 17 18 19 20 21 22 23 33 ...

Page 40: ...uretor cleaning solution b Blow out all of the passages and jets with compressed air 3 Check Sfloat chamber body Dirt Clean 4 Check Sfloat chamber rubber gasket Cracks damage wear Replace 5 Check Sfloat Damage Replace 6 Check Sneedle valve 1 Sneedle valve seat 2 Damage obstruction wear Replace the needle valve needle valve seat and O ring as a set 7 Check SO ring 3 Damage wear Replace the needle v...

Page 41: ...mage Replace 10 Check Sjet needle kit 1 Sneedle jet 2 Smain jet 3 Smain jet holder 4 Spilot jet 5 Spilot screw 6 Bends damage wear Replace Obstruction Clean Blow out the jets with compressed air 11 Check Spiston valve movement Insert the piston valve into the carburetor body and move it up and down Tightness Replace the piston valve 12 Check Sstarter plunger 1 Sstarter plunger spring 2 Bends crack...

Page 42: ...487 ASSEMBLING THE CARBURETOR SBefor assembling the carburetor wash all of the parts in a petroleum based solvent SAlways use a new gasket 1 Install Sneedle jet Smain jet 1 Smain jet holder 2 Spilot jet 3 2 Install Sneedle valve seat 1 3 Install Sfloat 1 Sneedle valve Sfloat pin 2 Install the float pin from the side opposite the ar row 36 ...

Page 43: ...1 450 X 1 650 r min Refer to ADJUSTING THE ENGINE IDLING SPEED 2 Adjust Sthrottle cable free play Throttle cable free play at the flange of the throttle grip 3 X 5 mm Refer to ADJUSTING THE THROTTLE CABLE FREE PLAY EAS00498 MEASURING AND ADJUSTING THE FUEL LEVEL 1 Measure Sfuel level a Out of specification Adjust Fuel level below the float chamber mating surface 0 X 2 0 mm 37 ...

Page 44: ...he fuel drain screw 3 e Hold the fuel level gauge vertically next to the float chamber f Measure the fuel level a 2 Adjust Sfuel level a Remove the carburetor b Check the needle valve seat and needle valve c If either is worn replace them as a set d If both are fine adjust the float level by slight ly bending the float tang 1 e Install the carburetor f Measure the fuel level again g Repeat steps a...

Page 45: ...Meter gear unit assembly Brake disc 2 1 1 1 1 1 1 Remove the parts in the order listed Place the motorcycle on a suitable stand so that the front wheel is elevated For installation reverse the removal procedure NOTE Refer to REMOVING INSTALLING THE FRONT WHEEL section in chapter 6 Manual No 5EK1 AE1 90 Nm 9 0 mSkg 13 Nm 1 3 mSkg EAS00512 CHASSIS FRONT WHEEL AND BRAKE DISC 39 ...

Page 46: ...her Chain pullers Wheel axle 1 1 1 1 1 1 1 2 1 Remove the parts in the order listed Place the motorcycle on a suitable stand so that the rear wheel is elevated Refer to REMOVING INSTALLING THE REAR WHEEL section in chapter 6 Manual No 5EK1 AE1 NOTE 90 Nm 9 0 mSkg REAR WHEEL AND REAR BRAKE CHAS REAR WHEEL AND REAR BRAKE REAR WHEEL 40 ...

Page 47: ...emarks 9 10 Rear wheel assembly Collar 1 2 Refer to REMOVING INSTALLING THE REAR WHEEL section in chapter 6 Manual No 5EK1 AE1 For installation reverse the removal procedure 90 Nm 9 0 mSkg REAR WHEEL AND REAR BRAKE CHAS 41 ...

Page 48: ...t Shoe plate Nuts Driven sprocket 1 6 1 Remove the parts in the order listed For installation reverse the removal procedure Refer to ASSEMBLYNG THE REAR WHEEL section in chapter 6 Manual No 5EK1 AE1 43 Nm 4 3 mSkg REAR WHEEL AND REAR BRAKE CHAS REAR BRAKE AND REAR WHEEL SPROCKET 42 ...

Page 49: ...t Q ty Remarks Disassembling the rear wheel Bearing Spacer Oil seal Bearing 1 1 1 1 Disassemble the parts in the order listed For assembly reverse the disassembly procedure 1 2 3 4 REAR WHEEL AND REAR BRAKE CHAS 43 ...

Page 50: ...t fork assembly left Front fork assembly right 1 1 1 1 1 1 2 1 1 Remove the parts in the order listed Refer to FRONT WHEEL AND BRAKE DISC For installation reverse the removal procedure Refer to REMOVING INSTALLING THE FRONT FORK section in cahpter 6 Manual No 5EK1 AE1 Loosen the bolt NOTE 23 Nm 2 3 mSkg 23 Nm 2 3 mSkg 23 Nm 2 3 mSkg 30 Nm 3 0 mSkg FRONT FORK CHAS FRONT FORK 44 ...

Page 51: ...acket Master cylinder Housing throttle grip Throttle grip assembly Handlebar switch right Clutch switch Clutch cable 1 1 1 1 1 1 1 Remove the parts in the order listed Refer to INSTALLING THE HANDLEBAR section in chapter 6 Manual No 5EK1 AE1 20 Nm 2 0 mSkg HANDLEBAR CHAS HANDLEBAR 45 ...

Page 52: ...ver Starter cable holder Upper holders Handlebar 1 1 1 1 2 1 Refer to REMOVING THE HANDLEBAR section in chapter 6 Manual No 5EK1 AE1 For installation reverse the removal procedure Refer to INSTALLING THE HANDLEBAR section in chapter 6 Manual No 5EK1 AE1 20 Nm 2 0 mSkg HANDLEBAR CHAS 46 ...

Page 53: ...er assembly Headlight stay Steering stem nut Handlebar crown Lock washer Upper ring nut Rubber washer Lower ring nut 1 1 1 1 1 1 1 2 1 1 1 1 1 1 Remove the parts in the order listed Refer to FRONT FORK Refer to HANDLEBAR Disconnect the connector Refer to INSTALLING THE STEERING HEAD section chapter 6 Manual No 5EK1 AE1 NOTE 90 Nm 9 0 mSkg 1st 38 Nm 3 8 mSkg 2nd 18 Nm 1 8 mSkg STEERING HEAD CHAS ST...

Page 54: ...race ccver Lower bracket Ball race upper Ball Ball Ball race center Ball race lower 1 1 1 22 19 1 1 For installation reverse the removal procedure Refer to INSTALLING THE STEERING section in chapter 6 Manual No 5EK1 AE1 90 Nm 9 0 mSkg 1st 38 Nm 3 8 mSkg 2nd 18 Nm 1 8 mSkg 48 ...

Page 55: ...I magneto 2 Neutral switch 4 Battery 6 Fuse 10 Engine stop switch 11 Main switch 13 Diode 14 C D I unit 15 Ignition coil 16 Spark plug 22 Neutral relay 24 Reed switch EAS00734 ELECTRLCAL SYSTEM IGNITION SYSTEM CIRCUIT DIAGRAM 49 ...

Page 56: ...tation the result is acceptable SIs the reed switch OK Replace the reed switch SRemove the meter assembly SConnect the pocket tester Ω 1 to the reed switch coupler as shown 1 Reed switch EAS00798 Tester positive probe white black Tester negative probe red blue 1 2 Properly connect or repair the ignition system CHECKING THE IGNITION SYSTEM 1 The speedometer fail to come on 50 ...

Page 57: ...light 27 Turn signal indicator light 28 Hi beam indicator light 29 Left handlebar switch 30 Horn switch 31 Turn signal switch 32 Light switch 33 Dimmer switch 34 Front brake light switch 35 Rear brake light switch 36 Rear turn signal light right 37 Front turn signal light right 38 Front turn signal light left 39 Rear turn signal light left 40 Headlight 41 Auxiliary light 42 Tail Brake light Sb Sky...

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