Yamaha YZ125D 2013 Owner's Service Manual
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Yamaha YZ125D 2013 Owner's Service Manual

Yamaha YZ125D 2013 Owner's Service Manual

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2013
q Read this manual carefully before operating this vehicle.
OWNER'S SERVICE MANUAL
YZ125D
LIT-11626-26-48
1SR-28199-11

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Summary of Contents for Yamaha YZ125D 2013

  • Page 1 2013 q Read this manual carefully before operating this vehicle. OWNER’S SERVICE MANUAL YZ125D LIT-11626-26-48 1SR-28199-11...
  • Page 2 Read this manual carefully before operating this vehicle. This manual should stay with this vehicle if it is sold.
  • Page 3 YZ125D OWNER'S SERVICE MANUAL ©2012 by Yamaha Motor Corporation, U.S.A. 1st Edition, September 2012 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Corporation U.S.A. is expressly prohibited. Printed in Japan P/N. LIT-11626-26-48...

  • Page 4: Important Manual Information

    INTRODUCTION IMPORTANT MANUAL INFORMATION Congratulations on your purchase of a Yamaha YZ series. This model is the culmination of Particularly important information is distin- Yamaha's vast experience in the production of guished in this manual by the following nota- pacesetting racing machines. It represents the tions.

  • Page 5: Safety Information

    SAFETY INFORMATION • PARK THE MACHINE CAREFULLY; TURN OFF THE ENGINE. THIS MACHINE IS DESIGNED STRICTLY Always turn off the engine if you are going to FOR COMPETITION USE, ONLY ON A leave the machine. Do not park the machine CLOSED COURSE.
  • Page 6 YAMAHA MOTOR CORPORATION, U.S.A. YZ MOTORCYCLE LIMITED WARRANTY...

  • Page 7: Manual Format

    HOW TO USE THIS MANUAL FINDING THE REQUIRED PAGE 1. This manual consists of seven chapters; "General Information", "Specifications", "Regular inspec- tion and adjustments", "Engine", "Chassis", "Electrical" and "Tuning" 2. The table of contents is at the beginning of the manual. Look over the general layout of the book before finding then required chapter and item.
  • Page 8 HOW TO READ DESCRIPTIONS To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each removal and disassembly section. 1. An easy-to-see exploded diagram "1" is provided for removal and disassembly jobs. 2. Numbers "2" are given in the order of the jobs in the exploded diagram. A number that is enclosed by a circle indicates a disassembly step.

  • Page 9: Illustrated Symbols

    ILLUSTRATED SYMBOLS (Refer Illustrated symbols "1" to "7" are used to identi- to the illustration) fy the specifications appearing in the text. 1. With engine mounted 2. Filling fluid 3. Lubricant 4. Special tool 5. Tightening 6. Specified value, Service limit 7.
  • Page 10 MEMO...

  • Page 11: Table Of Contents

    TABLE OF CONTENTS GENERAL INFORMATION SPECIFICATIONS REGULAR INSPECTION AND ADJUSTMENTS ENGINE CHASSIS ELECTRICAL TUNING...

  • Page 12: General Information

    CONTENTS CHAPTER 1 GENERAL INFORMATION LOCATION OF IMPORTANT LABELS ..1-1 DESCRIPTION ........... 1-2 CONSUMER INFORMATION ....1-3 INCLUDED PARTS ........1-4 IMPORTANT INFORMATION ....1-5 CHECKING OF CONNECTION ....1-7 SPECIAL TOOLS........1-8 CONTROL FUNCTIONS ......1-11 STARTING AND BREAK-IN ....1-13 TORQUE-CHECK POINTS ......
  • Page 13 CHAPTER 4 ENGINE SEAT, FUEL TANK AND SIDE COVERS ..............4-2 EXHAUST PIPE AND SILENCER ..... 4-4 RADIATOR..........4-6 CARBURETOR AND REED VALVE ..4-9 CYLINDER HEAD, CYLINDER AND PISTON ............ 4-17 CLUTCH ........... 4-28 KICK SHAFT AND SHIFT SHAFT... 4-34 YPVS GOVERNOR ........
  • Page 14 CHAPTER 6 ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ........6-2 IGNITION SYSTEM ........6-4 CHAPTER 7 TUNING ENGINE ............7-1 CHASSIS..........7-10...

  • Page 15: Location Of Important Labels

    LOCATION OF IMPORTANT LABELS GENERAL INFORMATION LOCATION OF IMPORTANT LABELS Please read the following important labels carefully before operating this vehicle. For use only on a closed course Premium unleaded in sanctioned competition. gasoline only. This motorcycle does not meet 3FB-2415E-02 EPA noise and emissions standards and is not for general...
  • Page 16 DESCRIPTION DESCRIPTION 1. Clutch lever 14. Fuel cock 2. Engine stop switch 15. Air filter 3. Front brake lever 16. Drive chain 4. Throttle grip 17. Shift pedal 5. Radiator cap 18. Starter knob 6. Fuel tank cap 19. Front fork 7.

  • Page 17: Consumer Information

    There are two significant reasons for knowing the serial number of your machine: 1. When ordering parts, you can give the num- ber to your Yamaha dealer for positive iden- tification of the model you own. 2. If your machine is stolen, the authorities will need the number to search for and identify your machine.

  • Page 18: Included Parts

    INCLUDED PARTS INCLUDED PARTS NIPPLE WRENCH This nipple wrench "1" is used to tighten the DETACHABLE SIDESTAND spoke. This sidestand "1" is used to support only the machine when standing or transporting it. • Never apply additional force to the sides- tand.

  • Page 19: Preparation For Removal And Disassembly

    5. Keep away from fire. ALL REPLACEMENT PARTS 2. Use proper tools and cleaning equipment. 1. We recommend to use Yamaha genuine Refer to "SPECIAL TOOLS" section. parts for all replacements. Use oil and/or grease recommended by Yamaha for as- sembly and adjustment.

  • Page 20: Lock Washers/Plates And Cotter Pins

    IMPORTANT INFORMATION LOCK WASHERS/PLATES AND COTTER CIRCLIPS PINS 1. All circlips should be inspected carefully be- 1. All lock washers/plates "1" and cotter pins fore reassembly. Always replace piston pin must be replaced when they are removed. clips after one use. Replace distorted cir- Lock tab(s) should be bent along the bolt or clips.

  • Page 21: Checking Of Connection

    CHECKING OF CONNECTION CHECKING OF CONNECTION 7. Check for continuity with a tester. Dealing with stains, rust, moisture, etc. on the • If there in no continuity, clean the terminals. connector. • Be sure to perform the steps 1 to 7 listed 1.

  • Page 22: Special Tools

    SPECIAL TOOLS SPECIAL TOOLS The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised tech- niques. The shape and part number used for the special tool differ by country, so two types are pro- vided.
  • Page 23 SPECIAL TOOLS Tool name/Part number How to use Illustration Piston pin puller set This tool is used to remove YU-1304, 90890-01304 the piston pin. Fuel level gauge "1" This gauge is used to mea- YM-1312-A, 90890-01312 sure the fuel level in the float Fuel level gauge adaptor "2"...
  • Page 24 Dynamic spark tester This instrument is necessary YM-34487 for checking the ignition sys- Ignition checker tem components. 90890-06754 Yamaha Bond No. 1215 This sealant (Bond) is used ® (ThreeBond No. 1215) for crankcase mating surface, 90890-85505 etc. 1-10...

  • Page 25: Control Functions

    CONTROL FUNCTIONS CONTROL FUNCTIONS KICKSTARTER CRANK Rotate the kickstarter crank "1" away from the ENGINE STOP SWITCH engine. Push the starter down lightly with your The engine stop switch "1" is located on the left foot until the gears engage, then kick smoothly handlebar.

  • Page 26: Rear Brake Pedal

    CONTROL FUNCTIONS REAR BRAKE PEDAL The rear brake pedal "1" is located on the right side of the machine. Press down on the brake pedal to activate the rear brake. FUEL COCK The fuel cock supplies fuel from the tank to car- buretor and also filters the fuel.

  • Page 27: Starting And Break-In

    STARTING AND BREAK-IN STARTING AND BREAK-IN HANDLING NOTE FUEL Mix oil with the gas at the ratio specified below. Before starting the machine, perform the Always use fresh, name-brand gasoline, and checks in the pre-operation check list. mix the oil and gas the day of the race. Do not use premix that is more than a few hours old.

  • Page 28: Break-In Procedures

    STARTING AND BREAK-IN BREAK-IN PROCEDURES 1. Before starting the engine, fill the fuel tank  After the break-in or before each race, you with a break-in oil-fuel mixture as follows. must check the entire machine for loose Mixing oil: fittings and fasteners as per "TORQUE- YAMALUBE "2-R"...

  • Page 29: Torque-Check Points

    TORQUE-CHECK POINTS TORQUE-CHECK POINTS Frame construction Frame to rear frame Combined seat and fuel tank Fuel tank to frame Exhaust system Silencer to rear frame Engine mounting Frame to engine Engine bracket to engine Engine bracket to frame Steering Steering stem to handlebar Steering stem to frame Steering stem to upper bracket Upper bracket to handlebar...

  • Page 30: Cleaning And Storage

    CLEANING AND STORAGE CLEANING AND STORAGE STORAGE If your machine is to be stored for 60 days or CLEANING more, some preventive measures must be tak- Frequent cleaning of your machine will en- en to avoid deterioration. After cleaning the ma- hance its appearance, maintain good overall chine thoroughly, prepare it for storage as performance, and extend the life of many com-...

  • Page 31: Specifications

    GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model name: YZ125D (USA, CDN, AUS, NZ) YZ125 (EUROPE, ZA) Model code number: 1SR5 (USA, CDN) 1SR6 (EUROPE) 1SR8 (AUS, NZ, ZA) Dimensions: USA, AUS, NZ, ZA EUROPE, CDN Overall length 2,135 mm (84.1 in) 2,139 mm (84.2 in) Overall width 827 mm (32.6 in)
  • Page 32 GENERAL SPECIFICATIONS Spark plug: Type/Manufacturer BR9EVX/NGK (resistance type) 0.6–0.7 mm (0.024–0.028 in) Clutch type: Wet, multiple-disc Transmission: Primary reduction system Gear Primary reduction ratio 3.368 (64/19) Final drive Chain Secondary reduction ratio 3.692 (48/13) Transmission type Constant mesh, 6-speed Operation Left foot operation Gear ratio: 2.385 (31/13)
  • Page 33 GENERAL SPECIFICATIONS Wheel travel: Front wheel travel 300 mm (11.8 in) Rear wheel travel 315 mm (12.4 in) Electrical: Ignition system CDI magneto...

  • Page 34: Maintenance Specifications

    MAINTENANCE SPECIFICATIONS MAINTENANCE SPECIFICATIONS ENGINE Item Standard Limit Cylinder head: Combustion chamber volume 8.4 cm (0.296 Imp oz, 0.284 US oz) ---- Warp limit ---- 0.03 mm (0.0012 in) Cylinder: Bore size 54.000–54.014 mm (2.1260–2.1265 in) 54.1 mm (2.130 in) Taper limit ---- 0.05 mm...
  • Page 35 MAINTENANCE SPECIFICATIONS Item Standard Limit Crankshaft: Crank width "A" 55.90–55.95 mm (2.201–2.203 in) ---- Runout limit "C" 0.03 mm (0.0012 in) 0.05 mm (0.0020 in) Connecting rod big end side clearance 0.06–0.64 mm (0.002–0.025 in) ---- "D" Small end free play "F" 0.8–1.0 mm (0.031–0.039 in) 2.0 mm (0.08 in)
  • Page 36 MAINTENANCE SPECIFICATIONS Item Standard Limit Carburetor: USA, CDN EUROPE AUS, NZ, ZA Type/Manufacturer TMXχ38SS ← ← /MIKUNI I.D. mark 1C37 51 1C36 41 ---- ← Main jet (M.J.) #430 ---- ← ← Jet needle-clip position (J.N.) 6BFY43-74- ---- ← ← Cutaway (C.A.) ---- ←...
  • Page 37 MAINTENANCE SPECIFICATIONS CHASSIS Item Standard Limit Steering system: Steering bearing type Taper roller bearing ---- Front suspension: USA, CDN, ZA, EUROPE AUS, NZ Front fork travel 300 mm (11.8 in) ---- ← Fork spring free length 454 mm (17.9 in) 449 mm ←...
  • Page 38 MAINTENANCE SPECIFICATIONS Item Standard Limit Wheel: Front wheel type Spoke wheel ---- Rear wheel type Spoke wheel ---- Front rim size/material 21 × 1.60/Aluminum ---- Rear rim size/material 19 × 1.85/Aluminum ---- Rim runout limit: Radial ---- 2.0 mm (0.08 in) Lateral ---- 2.0 mm...
  • Page 39 44–66 Ωat 20 °C (68 °F) (Black- ---- Green/Blue) Pickup coil resistance (color) 248–372 Ωat 20 °C (68 °F) (White/ ---- Blue-White/Red) CDI unit-model/manufacturer 1C3-10/YAMAHA (USA, CDN) ---- 1SR-00/YAMAHA (EUROPE, AUS, ZA, NZ) Ignition coil: Model/manufacturer 1C3-00/YAMAHA ---- Minimum spark gap 6 mm (0.24 in)

  • Page 40: Tightening Torques

    TIGHTENING TORQUES TIGHTENING TORQUES ENGINE △ - marked portion shall be checked for torque tightening after break-in or before each race. Threa Item Q'ty Tightening torque Remarks d size Spark plug M14S 20 Nm (2.0 m•kg, 14 ft•lb) Copper Cylinder head (nut) 28 Nm (2.8 m•kg, 20 ft•lb) washer Cylinder head (stud)
  • Page 41 TIGHTENING TORQUES Threa Item Q'ty Tightening torque Remarks d size Holder 10 Nm (1.0 m•kg, 7.2 ft•lb) Copper Oil check bolt 10 Nm (1.0 m•kg, 7.2 ft•lb) washer Copper Oil drain bolt 20 Nm (2.0 m•kg, 14 ft•lb) washer Kickstarter crank 10 Nm (1.0 m•kg, 7.2 ft•lb) Clutch cover 10 Nm (1.0 m•kg, 7.2 ft•lb)
  • Page 42 TIGHTENING TORQUES CHASSIS △ - marked portion shall be checked for torque tightening after break-in or before each race. Threa Item Q'ty Tightening torque Remarks d size △ Upper bracket and outer tube 21 Nm (2.1 m•kg, 15 ft•lb) △ Lower bracket and outer tube 21 Nm (2.1 m•kg, 15 ft•lb) △...
  • Page 43 TIGHTENING TORQUES Threa Item Q'ty Tightening torque Remarks d size △ Brake caliper (front and rear) and 18 Nm (1.8 m•kg, 13 ft•lb) pad pin △ Brake caliper (front and rear) and 6 Nm (0.6 m•kg, 4.3 ft•lb) bleed screw △...
  • Page 44 TIGHTENING TORQUES Threa Item Q'ty Tightening torque Remarks d size △ Swingarm and brake hose holder 3 Nm (0.3 m•kg, 2.2 ft•lb) Swingarm and patch 2 Nm (0.2 m•kg, 1.4 ft•lb) Drive chain tensioner 16 Nm (1.6 m•kg, 11 ft•lb) Drive chain support and swingarm 7 Nm (0.7 m•kg, 5.1 ft•lb) Seal guard and swingarm...

  • Page 45: General Torque Specifications

    TIGHTENING TORQUES GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasten- ers with standard I.S.O. pitch threads. Torque specifications for special components or as- semblies are included in the applicable sec- tions of this book. To avoid warpage, tighten multi-fastener assemblies in a crisscross fash- ion, in progressive stages, until full torque is reached.

  • Page 46: Definition Of Units

    TIGHTENING TORQUES DEFINITION OF UNITS Unit Read Definition Measure millimeter meter Length centimeter meter Length kilogram gram Weight Newton 1 kg × m/sec Force Newton meter N × m Torque m•kg Meter kilogram m × kg Torque Pascal Pressure N/mm Newton per millimeter N/mm Spring rate...
  • Page 47 MEMO...

  • Page 48: Cable Routing Diagram

    CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM 2-17...
  • Page 49 CABLE ROUTING DIAGRAM 1. Engine stop switch lead N. Tighten the clamp with its bolt head facing 2. Throttle cable the left side of the chassis (on both sides of 3. Clutch cable the carburetor joint and the air filter joint). 4.
  • Page 50 CABLE ROUTING DIAGRAM 2-19...
  • Page 51 CABLE ROUTING DIAGRAM 1. High tension cord 2. Engine stop switch lead 3. Ignition coil lead 4. Clamp 5. CDI unit 6. CDI unit band 7. Radiator breather hose 8. CDI magneto lead 9. Connector cover 10. Throttle cable 11. Clutch cable 12.
  • Page 52 CABLE ROUTING DIAGRAM 2-21...
  • Page 53 CABLE ROUTING DIAGRAM 1. Master cylinder 2. Brake hose holder 3. Brake hose A. Install the brake hose so that its pipe por- tion directs as shown and lightly touches the projection on the caliper. B. Pass the brake hose into the brake hose holders.
  • Page 54 CABLE ROUTING DIAGRAM 2-23...
  • Page 55 CABLE ROUTING DIAGRAM 1. Brake hose 2. Master cylinder 3. Engine stop switch lead 4. Engine stop switch 5. Throttle cable 6. Clutch cable 7. Clamp 8. Cable guide A. Install the brake hose so that its pipe por- tion directs as shown and lightly touches the projection on the master cylinder.

  • Page 56: Regular Inspection And Adjustments

    If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer. • Periodic inspection is essential in making full use of the machine performance. The service life of the parts varies substantially according to the environment in which the machine runs (e.g., rain,...

  • Page 57: Maintenance Intervals

    MAINTENANCE INTERVALS Every Every Every After race third fifth As re- Item break Remarks (about (about (about quired 12.5 hours) hours) hours) TRANSMISSION Replace oil Recommended brand: YAMA- ● ● LUBE SAE 10W-40 API service SG type or higher JASO standard MA Inspect ●...
  • Page 58 MAINTENANCE INTERVALS Every Every Every After race third fifth As re- Item break Remarks (about (about (about quired 12.5 hours) hours) hours) OUTSIDE NUTS AND BOLTS Retighten Refer to "STARTING AND ● ● BREAK-IN" section in the CHAPTER 1. AIR FILTER Clean and lubricate Use foam air-filter oil or equiva- ●...
  • Page 59 Retighten sprocket bolt ● ● Inspect bearings ● Replace bearings ● Lubricate Lithium base grease ● THROTTLE, CONTROL CABLE Check routing and con- ● ● nection Lubricate Yamaha cable lube or SAE ● ● 10W-40 motor oil...

  • Page 60: Pre-Operation Inspection And Maintenance

    PRE-OPERATION INSPECTION AND MAINTENANCE PRE-OPERATION INSPECTION AND MAINTENANCE Before riding for break-in operation, practice or a race, make sure the machine is in good operating condition. Before using this machine, check the following points. GENERAL INSPECTION AND MAINTENANCE Item Routine Page Check that coolant is filled up to the radiator cap.

  • Page 61: Engine

    ENGINE ENGINE CHANGING THE COOLANT CHECKING THE COOLANT LEVEL Do not remove the radiator cap when the en- gine is hot. Do not remove the radiator cap "1", drain bolt and hoses when the engine and radia- tor are hot. Scalding hot fluid and steam Take care so that coolant does not splash may be blown out under pressure, which on painted surfaces.

  • Page 62: Checking The Radiator Cap Opening Pressure

    ENGINE CHECKING THE RADIATOR CAP 1. Inspect: • Do not mix more than one type of ethylene • Seal (radiator cap) "1" glycol antifreeze containing corrosion in- • Valve and valve seat "2" hibitors for aluminum engine. Crack/damage → Replace. •...

  • Page 63: Checking The Cooling System

    ENGINE CHECKING THE COOLING SYSTEM ADJUSTING THE CLUTCH LEVER FREE 1. Inspect: PLAY • Coolant level 1. Check: 2. Attach: • Clutch lever free play "a" • Radiator cap tester "1" and adapter "2" Out of specification → Adjust. Radiator cap tester: Clutch lever free play "a"...

  • Page 64: Adjusting The Throttle Grip Free Play

    ENGINE 3. Install: • Cap "1" After adjusting the throttle grip free play, • Boot "2" turn the handlebar to the right and to the left to ensure that this does not cause the en- Place the tip "a" of the cap in the boot. gine idling speed to change.

  • Page 65: Cleaning The Air Filter Element

    ENGINE CLEANING THE AIR FILTER ELEMENT 4. Apply: • Foam-air-filter oil or equivalent oil to the ele- ment Proper air filter maintenance is the biggest key to preventing premature engine wear and dam- age. Squeeze out the excess oil. Element should be wet but not dripping.

  • Page 66: Checking The Transmission Oil Level

    ENGINE 7. Install: c. Inspect the gasket (oil check bolt), replace if • Air filter element "1" damaged. • Washer d. Tighten the oil check bolt. • Fitting bolt Oil check bolt: Fitting bolt: 10 Nm (1.0 m•kg, 7.2 ft•lb) 2 Nm (0.2 m•kg, 1.4 ft•lb) Align the projection "a"...

  • Page 67: Adjusting The Engine Idling Speed

    ENGINE 5. Install: ADJUSTING THE ENGINE IDLING SPEED • Aluminum washer 1. Start the engine and thoroughly warm it up. • Oil drain bolt "1" 2. Adjust: • Engine idling speed Oil drain bolt: 20 Nm (2.0 m•kg, 14 ft•lb) Adjustment steps: 6.

  • Page 68: Chassis

    CHASSIS CHASSIS d. Place the other end of the tube into a con- tainer. BLEEDING THE HYDRAULIC BRAKE e. Slowly apply the brake lever or pedal sever- SYSTEM al times. f. Pull the lever in or push down on the pedal. Hold the lever or pedal in position.

  • Page 69: Adjusting The Rear Brake

    CHASSIS 2. Remove: 2. Adjust: • Brake lever cover • Brake pedal height 3. Adjust: • Brake lever position Pedal height adjustment steps: a. Loosen the locknut "1". Brake lever position adjustment steps: b. Turn the adjusting nut "2" until the pedal a.

  • Page 70: Brake Pads

    CHASSIS CHECKING AND REPLACING THE FRONT d. Remove the pad pin and brake pads "4". BRAKE PADS 1. Inspect: • Brake pad thickness "a" Out of specification → Replace as a set. Brake pad thickness "a": 4.4 mm (0.17 in) <Limit>: 1.0 mm (0.04 in) e.
  • Page 71 CHASSIS i. Install the brake caliper "8" and tighten the CHECKING AND REPLACING THE REAR pad pin "9". BRAKE PADS 1. Inspect: Bolt (brake caliper): • Brake pad thickness "a" 28 Nm (2.8 m•kg, 20 ft•lb) Out of specification → Replace as a set. Pad pin: 18 Nm (1.8 m•kg, 13 ft•lb) Brake pad thickness "a":...
  • Page 72 CHASSIS d. Remove the pad pin "6" and brake pads "7". i. Install the brake caliper "12" and rear wheel "13". Refer to "FRONT WHEEL AND REAR WHEEL" section in the CHAPTER 5. j. Tighten the pad pin "14". Pad pin: 18 Nm (1.8 m•kg, 13 ft•lb) e.

  • Page 73: Checking The Rear Brake Pad Insulator

    CHASSIS CHECKING THE REAR BRAKE PAD CHECKING THE SPROCKET INSULATOR 1. Inspect: 1. Remove: • Sprocket teeth "a" • Brake pad Excessive wear → Replace. Refer to "CHECKING AND REPLACING THE REAR BRAKE PADS" section. Replace the drive sprocket, rear wheel sprock- 2.

  • Page 74: Adjusting The Drive Chain Slack

    CHASSIS 2. Remove: 5. Install: • Master link clip • Drive chain "1" • Joint "1" • Joint "2" • Drive chain "2" • Master link clip "3" Be sure to install the master link clip to the direction as shown. 3.

  • Page 75: Checking The Front Fork

    CHASSIS e. Tighten the locknuts. Locknut: 19 Nm (1.9 m•kg, 13 ft•lb) CHECKING THE FRONT FORK 1. Inspect: • Front fork smooth action Operate the front brake and stroke the front fork. 3. Adjust: Unsmooth action/oil leakage → Repair or re- •...
  • Page 76 CHASSIS 2. Clean: Extent of adjustment: • Dust seal "a" • Oil seal "b" Maximum Minimum Fully turned in posi- 20 clicks out (from • Clean the dust seal and oil seal after every run. tion maximum position) • Apply the lithium soap base grease on the in- ner tube.

  • Page 77: Checking The Rear Shock Absorber

    CHASSIS 3. Measure: • Spring fitting length Standard fitting length: I.D. MARK/ Q'TY Length Red/1 258 mm (10.16 in) *252 mm (9.92 in) Red/2 264 mm (10.39 in) *258 mm (10.16 in) Red/3 255.5 mm (10.06 in) • STANDARD POSITION: *249.5 mm (9.82 in) This is the position which is back by the spe- cific number of clicks from the fully turned-in...
  • Page 78 CHASSIS ADJUSTING THE REAR SHOCK ABSORBER REBOUND DAMPING FORCE 1. Adjust: • Rebound damping force By turning the adjuster "1". Stiffer "a" → Increase the rebound damp- ing force. (Turn the adjuster "1" in.) Softer "b" → Decrease the rebound damp- ing force.
  • Page 79 CHASSIS ADJUSTING THE REAR SHOCK ADJUSTING THE REAR SHOCK ABSORBER LOW COMPRESSION ABSORBER HIGH COMPRESSION DAMPING FORCE DAMPING FORCE 1. Adjust: 1. Adjust: • Low compression damping force • High compression damping force By turning the adjuster "1". By turning the adjuster "1". Stiffer "a"...

  • Page 80: Checking The Tire Pressure

    CHASSIS CHECKING THE TIRE PRESSURE 2. Tighten: 1. Measure: • Spoke • Tire pressure (with a spoke nipple wrench "1") Out of specification → Adjust. Be sure to tighten these spokes before and af- Standard tire pressure: ter break-in. 100 kPa (1.0 kgf/cm , 15 psi) •...

  • Page 81: Checking And Adjusting The Steering Head

    CHASSIS CHECKING AND ADJUSTING THE 4. Adjust: STEERING HEAD • Steering ring nut 1. Place a stand under the engine to raise the front wheel off the ground. WARNING! Se- Steering ring nut adjustment steps: curely support the vehicle so that there is a.
  • Page 82 CHASSIS g. Check the steering stem by turning it lock to lock. If there is any binding, remove the steering stem assembly and inspect the steering bearings. h. Install the washer "5", upper bracket "6", washer "7", steering stem nut "8", handlebar "9", handlebar upper holders "10"...
  • Page 83 CHASSIS LUBRICATION To ensure smooth operation of all components, A. Use Yamaha cable lube or equivalent on lubricate your machine during setup, after these areas. break-in, and after every race. B. Use SAE 10W-40 motor oil or suitable 1. All control cable chain lubricants.

  • Page 84: Electrical

    ELECTRICAL ELECTRICAL 5. Tighten: • Spark plug CHECKING THE SPARK PLUG Spark plug: 1. Remove: 20 Nm (2.0 m•kg, 14 ft•lb) • Spark plug 2. Inspect: • Electrode "1" • Before installing a spark plug, clean the gas- Wear/damage → Replace. ket surface and plug surface.
  • Page 85 ELECTRICAL 3. Rotate the magneto rotor "1" until the piston 7. Adjust: reaches top dead center (TDC). When this • Ignition timing happens, the needle on the dial gauge will stop and reverse directions even though the Adjustment steps: rotor is being turned in the same direction. a.
  • Page 86 This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowl- edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas- sembly, or reassembly only by reference to this manual.

  • Page 87: Seat, Fuel Tank And Side Covers

    SEAT, FUEL TANK AND SIDE COVERS SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SEAT, FUEL TANK AND SIDE COVERS 19 Nm (1.9 m kg, 13 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 6 Nm (0.6 m kg, 4.3 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb)

  • Page 88: Removing The Side Cover

    SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SIDE COVER 1. Remove: • Bolt (side cover) • Side cover (left and right) "1" Draw the side cover downward to remove it be- cause its claws "a" are inserted in the air filter case.

  • Page 89: Exhaust Pipe And Silencer

    EXHAUST PIPE AND SILENCER EXHAUST PIPE AND SILENCER REMOVING THE EXHAUST PIPE AND SILENCER 12 Nm (1.2 m kg, 8.7 ft lb) 12 Nm (1.2 m kg, 8.7 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 12 Nm (1.2 m kg, 8.7 ft lb) 12 Nm (1.2 m kg, 8.7 ft lb) Order Part name...

  • Page 90: Changing The Silencer Fiber

    3. Replace: • Fiber "2" 4. Install: • Inner pipe ® Fully apply Quick gasket (Yamaha bond No.1215) or equivalent as shown. Yamaha bond No.1215 (Three ® Bond No.1215): 90890-85505 5. Install: • Bolt (fiber) "1" Bolt (fiber): 10 Nm (1.0 m•kg, 7.2 ft•lb) •...

  • Page 91: Removing The Radiator

    RADIATOR RADIATOR REMOVING THE RADIATOR 2 Nm (0.2 m kg, 1.4 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) Order Part name Q'ty...

  • Page 92: Handling Note

    RADIATOR HANDLING NOTE Do not remove the radiator cap when the en- gine and radiator are hot. Scalding hot fluid and steam may be blown out under pres- sure, which could cause serious injury. When the engine has cooled, open the radi- ator cap by the following procedure: Place a thick rag, like a towel, over the radi- ator cap, slowly rotate the cap counter-...
  • Page 93 RADIATOR 4. Tighten: • Radiator hose clamp 1, 3 "5" Radiator hose clamp 1, 3: 2 Nm (0.2 m•kg, 1.4 ft•lb) 5. Install: • Radiator guard "1" • Bolt (radiator guard) "2" Bolt (radiator guard): 10 Nm (1.0 m•kg, 7.2 ft•lb) Fit the hook "a"...

  • Page 94: Carburetor And Reed Valve

    CARBURETOR AND REED VALVE CARBURETOR AND REED VALVE REMOVING THE CARBURETOR AND REED VALVE 2 Nm (0.2 m kg, 1.4 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 1 Nm (0.1 m kg, 0.7 ft lb) Order Part name Q'ty...

  • Page 95: Disassembling The Carburetor

    CARBURETOR AND REED VALVE DISASSEMBLING THE CARBURETOR 4 Nm (0.4 m kg, 2.9 ft lb) Order Part name Q'ty Remarks Mixing chamber top Refer to removal section. Throttle valve Needle holder Jet needle Float chamber Needle jet cover Float pin Float Valve seat Main jet...

  • Page 96: Checking The Carburetor

    CARBURETOR AND REED VALVE HANDLING NOTE • Use a petroleum based solvent for cleaning. Blow out all passages and jets with com- Do not disassemble the venturi block "1" pressed air. and main nozzle "2" because it will cause a •...
  • Page 97 CARBURETOR AND REED VALVE CHECKING THE NEEDLE VALVE 1. Inspect: • Needle valve "1" • Valve seat "2" Grooved wear "a" → Replace. Dust "b" → Clean. Always replace the needle valve and valve seat as a set. CHECKING THE FILTER 1.

  • Page 98: Checking The Reed Valve

    CARBURETOR AND REED VALVE Keep the carburetor and fuel level gauge verti- cally when measuring the fuel level. e. If the fuel level is not within specification, in- spect the valve seat and needle valve. f. If either is worn, replace them both. g.

  • Page 99: Assembling The Carburetor

    CARBURETOR AND REED VALVE 2. Install: 2. Install: • Reed valve assembly "1" • Starter plunger "1" • Reed valve spacer "2" 3. Install: 3. Install: • Main jet holder "1" • Carburetor joint "1" • Main jet "2" • Bolt (carburetor joint) "2" •...
  • Page 100 CARBURETOR AND REED VALVE 5. Install: • Float chamber "1" • Plate "2" • Screw (float chamber) "3" 8. Install: • Mixing chamber top "1" • Screw (mixing chamber top) "2" To carburetor "3". 6. Install: • Jet needle "1" After installing, check the throttle grip for •...

  • Page 101: Installing The Carburetor

    CARBURETOR AND REED VALVE INSTALLING THE CARBURETOR 4. Adjust: 1. Install: • Idle speed • Carburetor "1" Refer to "ADJUSTING THE ENGINE IDLING SPEED" section in the CHAPTER 3. Install the projection between the carburetor joint slots. 2. Tighten: • Bolt (air filter joint) "1" Bolt (air filter joint): 2 Nm (0.2 m•kg, 1.4 ft•lb) •...

  • Page 102: Cylinder Head, Cylinder And Piston

    CYLINDER HEAD, CYLINDER AND PISTON CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE CYLINDER HEAD AND CYLINDER 20 Nm (2.0 m kg, 14 ft lb) 28 Nm (2.8 m kg, 20 ft lb) 34 Nm (3.4 m kg, 24 ft lb) 13 Nm (1.3 m kg, 9.4 ft lb) 30 Nm (3.0 m kg, 22 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb)
  • Page 103 CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE PISTON AND POWER VALVE 4 Nm (0.4 m kg, 2.9 ft lb) 8 Nm (0.8 m kg, 5.8 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) Order Part name Q'ty...

  • Page 104: Checking The Cylinder Head

    CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE PUSH ROD 1. Remove: • Bolt (push rod) "1" • Push rod "2" Set the collar "3" included in owner's tool kit to remove the bolt (push rod). 3. Remove: • Piston ring "1" Take care not to scratch the piston or damage the piston ring by expanding it more than nec- essary.

  • Page 105: Checking The Cylinder

    CYLINDER HEAD, CYLINDER AND PISTON 3. Measure: • Cylinder head warpage Out of specification → Resurface. Cylinder head warpage: Less than 0.03 mm (0.0012 in) Warpage measurement and resurfacing steps: a. Attach a straightedge "1" and a thickness gauge "2" on the cylinder head. 2.

  • Page 106: Checking The Piston

    CYLINDER HEAD, CYLINDER AND PISTON CHECKING THE PISTON PIN AND SMALL END BEARING 1. Inspect: • Piston pin • Small end bearing Signs of heat discoloration → Replace. CHECKING THE PISTON 1. Eliminate: • Carbon deposits From the piston crown "a" and ring groove "b".

  • Page 107: Checking The Piston Ring

    CYLINDER HEAD, CYLINDER AND PISTON 3. Check: • Free play (when the piston pin "1" is in place in the piston "2") There should be no noticeable for the play. Free play exists → Replace piston pin and/ or piston. 3.
  • Page 108 CYLINDER HEAD, CYLINDER AND PISTON Piston clearance: Standard <Limit> 0.040–0.045 mm 0.1 mm (0.004 in) (0.0016–0.0018 in) CHECKING THE COMBINATION OF PISTON AND CYLINDER 1. Check: • Cylinder mark "a" 3. Combination: Cylinder mark "a" Cylinder size Combine the piston and cylinder by the fol- 54.000–54.002 mm lowing chart.
  • Page 109 CYLINDER HEAD, CYLINDER AND PISTON Do not use a sharp instrument. Avoid scratch- ing the aluminum. 3. Install: • Thrust plate "1" • Screw (thrust plate) "2" Screw (thrust plate): INSTALLING THE POWER VALVE 4 Nm (0.4 m•kg, 2.9 ft•lb) 1.
  • Page 110 CYLINDER HEAD, CYLINDER AND PISTON INSTALLING THE PISTON RING AND 3. Install: PISTON • Piston "1" 1. Install: • Piston pin "2" • Piston ring "1" • Piston pin clip "3" • Take care not to scratch the piston or damage •...
  • Page 111 CYLINDER HEAD, CYLINDER AND PISTON INSTALLING THE CYLINDER HEAD AND 3. Install: CYLINDER • Nut (cylinder) "1" 1. Apply: Nut (cylinder): • Engine oil 30 Nm (3.0 m•kg, 22 ft•lb) To piston "1", piston ring "2" and cylinder surface. Tighten the nuts in stage, using a crisscross pattern.
  • Page 112 CYLINDER HEAD, CYLINDER AND PISTON 5. Install: 8. Install: • Gasket (power valve housing) • Engine bracket "1" • Power valve housing "1" • Bolt (engine bracket) "2" • Bolt (power valve housing) "2" Bolt (engine bracket): Bolt (power valve housing): 34 Nm (3.4 m•kg, 24 ft•lb) 4 Nm (0.4 m•kg, 2.9 ft•lb) •...

  • Page 113: Removing The Clutch

    CLUTCH CLUTCH REMOVING THE CLUTCH 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Refer to "CHANGING THE TRANS- Drain the transmission oil. MISSION OIL" section in the CHAP- TER 3.
  • Page 114 CLUTCH REMOVING THE CLUTCH BOSS 80 Nm (8.0 m kg, 58 ft lb) Order Part name Q'ty Remarks Push rod 1 Circlip Washer Bearing Ball Push rod 2 Nut (clutch boss) Refer to removal section. Lock washer Refer to removal section. Clutch boss Refer to removal section.
  • Page 115 CLUTCH REMOVING THE CLUTCH BOSS CHECKING THE PRIMARY DRIVEN GEAR 1. Remove: 1. Check: • Nut "1" • Circumferential play Free play exists → Replace. • Lock washer "2" • Gear teeth "a" • Clutch boss "3" Wear/damage → Replace. Straighten the lock washer tab and use the clutch holding tool "4"...
  • Page 116 CLUTCH CHECKING THE CLUTCH PLATES INSTALLING THE PUSH LEVER SHAFT 1. Measure: 1. Install: • Clutch plate warpage • Push lever shaft "1" Out of specification → Replace clutch plate as a set. Apply the lithium soap base grease on the oil Use a surface plate "1"...
  • Page 117 CLUTCH 3. Install: • Lock washer "1" • Install the clutch plates and friction plates al- • Nut (clutch boss) "2" ternately on the clutch boss, starting with a friction plate and ending with a friction plate. Nut (clutch boss): •...
  • Page 118 CLUTCH 8. Install: 11.Install: • Pressure plate "1" • Clutch cover "1" • Bolt (clutch cover) "2" Bolt (clutch cover): 10 Nm (1.0 m•kg, 7.2 ft•lb) Tighten the bolts in stage, using a crisscross pattern. 9. Install: • Clutch spring "1" •...

  • Page 119: Kick Shaft And Shift Shaft

    KICK SHAFT AND SHIFT SHAFT KICK SHAFT AND SHIFT SHAFT REMOVING THE PRIMARY DRIVE GEAR Order Part name Q'ty Remarks Refer to "CHANGING THE TRANS- Drain the transmission oil. MISSION OIL" section in the CHAP- TER 3. Clutch cable Disconnect at engine side. Bolt (brake pedal) Shift the brake pedal downward.
  • Page 120 KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT AND SHIFT SHAFT Order Part name Q'ty Remarks Kick idle gear Kick shaft assembly Refer to removal section. Shift pedal Shift shaft Roller Shift guide Refer to removal section. Shift lever assembly Refer to removal section.
  • Page 121 KICK SHAFT AND SHIFT SHAFT REMOVING THE PRIMARY DRIVE GEAR REMOVING THE SEGMENT 1. Loosen: 1. Remove: • Bolt (primary drive gear) "1" • Bolt (segment) "1" • Segment "2" Place an aluminum plate "a" between the teeth of the primary drive gear "2" and driven gear Turn the segment counterclockwise until it "3".
  • Page 122 KICK SHAFT AND SHIFT SHAFT CHECKING THE KICK GEAR CLIP CHECKING THE STOPPER LEVER 1. Measure: 1. Inspect: • Kick clip friction force • Stopper lever "1" Out of specification → Replace. Wear/damage → Replace. Use a spring gauge "1". •...

  • Page 123: Installing The Segment

    KICK SHAFT AND SHIFT SHAFT INSTALLING THE SEGMENT 1. Install: • Segment "1" • Bolt (segment) Bolt (segment): 30 Nm (3.0 m•kg, 22 ft•lb) Align the notch "a" on the segment with the pin "b" on the shift cam. INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY If the segment gets an impact, it may be 1.

  • Page 124: Installing The Shift Shaft

    KICK SHAFT AND SHIFT SHAFT 4. Install: 2. Install: • Bolt (shift guide) "1" • Spring guide "1" Bolt (shift guide): Slide the spring guide into the kick shaft, make 10 Nm (1.0 m•kg, 7.2 ft•lb) sure the groove "a" in the spring guide fits on the stopper of the torsion spring.

  • Page 125: Installing The Kick Idle Gear

    KICK SHAFT AND SHIFT SHAFT 3. Tighten: • Bolt (primary drive gear) "1" Bolt (primary drive gear): 48 Nm (4.8 m•kg, 35 ft•lb) Place an aluminum plate "a" between the teeth of the primary drive gear and driven gear. INSTALLING THE KICK IDLE GEAR 1.
  • Page 126 KICK SHAFT AND SHIFT SHAFT 6. Install: • Bolt [crankcase cover (right)] "1" Bolt [crankcase cover (right)] : 10 Nm (1.0 m•kg, 7.2 ft•lb) Tighten the bolts in stage, using a crisscross pattern. 7. Install: • Kick starter "1" • Plain washer "2" •...

  • Page 127: Ypvs Governor

    YPVS GOVERNOR YPVS GOVERNOR REMOVING THE YPVS GOVERNOR Order Part name Q'ty Remarks Refer to "KICK SHAFT AND SHIFT Right crankcase cover SHAFT" section. Governor assembly Dowel pin Refer to removal section. Retainer Ball Retainer weight Plain washer Thrust bearing Collar Plate Compression spring...

  • Page 128: Checking The Bearing

    YPVS GOVERNOR REMOVING THE GOVERNOR INSTALLING THE GOVERNOR 1. Remove: 1. Install: • Dowel pin "1" • Governor gear "1" • Compression spring "2" • Plate "3" While compressing the spring, remove the • Washer "4" dowel pin. • Thrust bearing "5" •...
  • Page 129 YPVS GOVERNOR 3. Install: • Dowel pin "1" • While compressing the spring, install the dow- el pin. • Make sure the dowel pin fits into the groove "a" in the retainer. 4. Install: • Governor assembly "1" Align the groove "a" in the governor with the fork "b"...

  • Page 130: Disassembling The Water Pump

    WATER PUMP WATER PUMP DISASSEMBLING THE WATER PUMP Order Part name Q'ty Remarks Refer to "KICK SHAFT AND SHIFT Crankcase cover (right) SHAFT" section. Water pump housing cover Impeller shaft gear Dowel pin Plain washer Impeller shaft assembly Bearing Refer to removal section. Oil seal Refer to removal section.
  • Page 131 WATER PUMP REMOVING THE OIL SEAL CHECKING THE IMPELLER SHAFT GEAR 1. Inspect: • Gear teeth "a" • Replace the oil seal when transmission oil or Wear/damage → Replace. coolant leaks out from the water pump hous- ing hole at the bottom. •...
  • Page 132 WATER PUMP • Washer "5" • Circlip "6" Install the Impeller shaft gear with the dowel pin fitted in the groove "a" in the same gear. 2. Install: • Bearing "1" Install the bearing by pressing its outer race parallel. 3.

  • Page 133: Cdi Magneto

    CDI MAGNETO CDI MAGNETO REMOVING THE CDI MAGNETO Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND Seat and fuel tank SIDE COVERS" section. Bolt (Radiator) Refer to "RADIATOR" section. Disconnect the CDI magneto lead. Left crankcase cover Nut (rotor) Refer to removal section.

  • Page 134: Removing The Rotor

    CDI MAGNETO REMOVING THE ROTOR CHECKING THE CDI MAGNETO 1. Remove: 1. Inspect: • Nut (rotor) "1" • Rotor inner surface "a" • Washer "2" • Stator outer surface "b" Use the rotor holding tool "3". Damage → Inspect the crankshaft runout and crankshaft bearing.
  • Page 135 CDI MAGNETO 2. Install: 5. Tighten: • Woodruff key "1" • Screw (stator) "1" • Rotor "2" Screw (stator): 7 Nm (0.7 m•kg, 5.1 ft•lb) • Clean the tapered portions of the crankshaft and rotor. • When installing the woodruff key, make sure that its flat surface "a"...

  • Page 136: Engine Removal

    ENGINE REMOVAL ENGINE REMOVAL REMOVING THE ENGINE 26 Nm (2.6 m kg, 19 ft lb) 34 Nm (3.4 m kg, 24 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 85 Nm (8.5 m kg, 61 ft lb) 75 Nm (7.5 m kg, 54 ft lb) Order...
  • Page 137 ENGINE REMOVAL 26 Nm (2.6 m kg, 19 ft lb) 34 Nm (3.4 m kg, 24 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 85 Nm (8.5 m kg, 61 ft lb) 75 Nm (7.5 m kg, 54 ft lb) Order...

  • Page 138: Handling Note

    ENGINE REMOVAL HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE DRIVE SPROCKET 1. Remove: • Nut (drive sprocket) "1" • Lock washer "2" 2. Remove: • Straighten the lock washer tab. •...

  • Page 139: Installing The Drive Sprocket

    ENGINE REMOVAL INSTALLING THE DRIVE SPROCKET Nut [engine mounting bolt (upper)]: 1. Install: 34 Nm (3.4 m•kg, 24 ft•lb) • Drive sprocket "1" • Drive chain "2" Apply the molybdenum disulfide grease on the Install the drive sprocket together with the drive pivot shaft.

  • Page 140: Crankcase And Crankshaft

    CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT REMOVING THE CRANKSHAFT 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 14 Nm (1.4 m kg, 10 ft lb) 20 Nm (2.0 m kg, 14 ft lb) Order Part name Q'ty...
  • Page 141 CRANKCASE AND CRANKSHAFT 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 14 Nm (1.4 m kg, 10 ft lb) 20 Nm (2.0 m kg, 14 ft lb) Order Part name Q'ty Remarks Bolt [L=75 mm (2.95 in)] Holder Crankcase (right)

  • Page 142: Removing The Segment

    CRANKCASE AND CRANKSHAFT REMOVING THE SEGMENT 1. Remove: • Bolt (segment) "1" • Segment "2" Turn the segment counterclockwise until it stops and loosen the bolt. If the segment gets an impact, it may be REMOVING THE CRANKSHAFT damaged. Take care not to give an impact to 1.

  • Page 143: Checking The Crankcase

    CRANKCASE AND CRANKSHAFT 3. Inspect: • Oil seal "1" Damage → Replace. CHECKING THE CRANKSHAFT 1. Measure: • Runout limit "a" • Small end free play limit "b" • Connecting rod big end side clearance "c" • Crank width "d" Out of specification →...

  • Page 144: Installing The Crankshaft

    CRANKCASE AND CRANKSHAFT INSTALLING THE CRANKSHAFT 1. Install: • Crankshaft "1" Use the crankshaft installing tools "2", "3", "4". Crankshaft installing pot "2": YU-90050/90890-01274 Crankshaft installing bolt "3": YU-90050/90890-01275 Adapter "4": INSTALLING THE CRANKCASE BEARING YU-90063/90890-01278 1. Install: • Bearing "1" •...
  • Page 145 • Apply molybdenum disulfide grease to the surface "a" where the crankshaft and bearing come in contact. 3. Apply: • Use two plain washers (Yamaha genuine: • Sealant 90201-243K3) "5" or the ones of a size as On the right crankcase "1".
  • Page 146 CRANKCASE AND CRANKSHAFT • When installing the segment onto the shift cam "3", align the punch mark "a" with the dowel pin "b". • Turn the segment clockwise until it stops and tighten the bolt. If the segment gets an impact, it may be damaged.

  • Page 147: Transmission, Shift Cam And Shift Fork

    TRANSMISSION, SHIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION, SHIFT CAM AND SHIFT FORK 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Refer to "ENGINE REMOVAL"...

  • Page 148: Removing The Transmission

    TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION CHECKING THE BEARING 1. Remove: 1. Inspect: • Main axle "1" • Bearing "1" • Drive axle "2" Rotate inner race with a finger. Rough spot/seizure → Replace. • Tap lightly on the transmission drive axle with a soft hammer to remove.

  • Page 149: Installing The Transmission

    TRANSMISSION, SHIFT CAM AND SHIFT FORK 3. Check: 2. Install: • Shift fork movement • 2nd wheel gear (29T) "1" On its guide bar. • 5th wheel gear (24T) "2" Unsmooth operation → Replace shift fork • 3rd wheel gear (27T) "3" and/or guide bar.
  • Page 150 TRANSMISSION, SHIFT CAM AND SHIFT FORK INSTALLING THE SHIFT CAM AND SHIFT FORK 1. Install: • Shift fork 1 (L) "1" • Shift fork 2 (C) "2" • Shift fork 3 (R) "3" • Mesh the shift fork 1 (L) with the 5th wheel gear "4"...
  • Page 151 TRANSMISSION, SHIFT CAM AND SHIFT FORK 2. Install: • Shift cam "1" • Apply the transmission oil on the shift cam. • Install the shift cam while holding up the 5th wheel gear "2" and keeping the shift fork 1 "3" moved in the direction of the arrow.
  • Page 152 This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowl- edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas- sembly, or reassembly only by reference to this manual.

  • Page 153: Front Wheel And Rear Wheel

    FRONT WHEEL AND REAR WHEEL FRONT WHEEL AND REAR WHEEL REMOVING THE FRONT WHEEL Order Part name Q'ty Remarks Hold the machine by placing the suit- Refer to "HANDLING NOTE". able stand under the engine. Bolt (axle holder) Only loosening. Nut (front wheel axle) Front wheel axle Front wheel...

  • Page 154: Removing The Rear Wheel

    FRONT WHEEL AND REAR WHEEL REMOVING THE REAR WHEEL Order Part name Q'ty Remarks Hold the machine by placing the suit- Refer to "HANDLING NOTE". able stand under the engine. Nut (rear wheel axle) Rear wheel axle Drive chain puller Rear wheel Refer to removal section.
  • Page 155 FRONT WHEEL AND REAR WHEEL HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE REAR WHEEL 1. Remove: • Wheel "1" Push the wheel forward and remove the drive 2. Inspect: chain "2". •...

  • Page 156: Checking The Brake Disc

    FRONT WHEEL AND REAR WHEEL CHECKING THE BRAKE DISC 1. Measure: • Apply the lithium soap base grease on the • Brake disc deflection (only rear brake disc) bearing and oil seal lip when installing. • Use a socket that matches the outside diam- Use the dial gauge "1".
  • Page 157 FRONT WHEEL AND REAR WHEEL 3. Install: 6. Install: • Collar "1" • Nut (wheel axle) "1" Nut (wheel axle): • Apply the lithium soap base grease on the oil 105 Nm (10.5 m•kg, 75 ft•lb) seal lip. • Install the collars with their projections "a" fac- ing the wheel.

  • Page 158: Installing The Rear Wheel

    FRONT WHEEL AND REAR WHEEL INSTALLING THE REAR WHEEL 1. Install: • Bearing (right) "1" • Circlip "2" • Spacer "3" • Bearing (left) "4" • Oil seal "5" • Apply the lithium soap base grease on the bearing and oil seal lip when installing. •...
  • Page 159 FRONT WHEEL AND REAR WHEEL 5. Install: 8. Install: • Wheel • Right drive chain puller "1" • Washer "2" • Nut (wheel axle) "3" Install the brake disc "1" between the brake pads "2" correctly. Temporarily tighten the nut (wheel axle) at this point.

  • Page 160: Front Brake And Rear Brake

    FRONT BRAKE AND REAR BRAKE FRONT BRAKE AND REAR BRAKE REMOVING THE FRONT BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suit- Refer to "HANDLING NOTE". able stand under the engine. Drain the brake fluid. Refer to removal section. Brake hose holder (protector) Union bolt Brake hose...
  • Page 161 FRONT BRAKE AND REAR BRAKE REMOVING THE REAR BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suit- Refer to "HANDLING NOTE". able stand under the engine. Refer to "FRONT WHEEL AND Rear wheel REAR WHEEL" section. Drain the brake fluid.
  • Page 162 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE CALIPER Order Part name Q'ty Remarks A. Front B. Rear Pad pin Brake pad Pad support Brake caliper piston 1 Refer to removal section. Brake caliper piston dust seal 1 Refer to removal section. Brake caliper piston seal 1 Refer to removal section.
  • Page 163 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE MASTER CYLINDER Order Part name Q'ty Remarks A. Front B. Rear Brake master cylinder cap Diaphragm Reservoir float Push rod (Front) Brake master cylinder boot Circlip Use a long nose circlip pliers. Washer Push rod (Rear) Brake master cylinder kit...
  • Page 164 FRONT BRAKE AND REAR BRAKE HANDLING NOTE 3. Loosen the bleed screw and drain the brake fluid while pulling the lever in or pushing down on the pedal. Support the machine securely so there is no danger of it falling over. •...
  • Page 165 FRONT BRAKE AND REAR BRAKE REMOVING THE BRAKE CALIPER PISTON SEAL KIT 1. Remove: • Brake caliper piston dust seal "1" • Brake caliper piston seal "2" Remove the brake caliper piston seals and brake caliper piston dust seals by pushing them with a finger.

  • Page 166: Installing The Brake Caliper Piston

    FRONT BRAKE AND REAR BRAKE CHECKING THE BRAKE CALIPER HANDLING NOTE 1. Inspect: • Brake caliper cylinder inner surface "a" • All internal parts should be cleaned in new Wear/score marks → Replace brake caliper brake fluid only. assembly. • Internal parts should be lubricated with brake fluid when installed.

  • Page 167: Installing The Front Brake Caliper

    FRONT BRAKE AND REAR BRAKE • Install the brake pads with their projections "a" into the brake caliper recesses "b". • Temporarily tighten the pad pin at this point. A. Front B. Rear 3. Install: • Brake caliper piston "1" 2.
  • Page 168 FRONT BRAKE AND REAR BRAKE INSTALLING THE BRAKE MASTER CYLINDER KIT 1. Clean: • Brake master cylinder • Brake master cylinder kit Clean them with brake fluid. 2. Install: • Brake master cylinder cup (primary) "1" • Brake master cylinder cup (secondary) "2" To brake master cylinder piston "3".

  • Page 169: Installing The Front Brake Master Cylinder

    FRONT BRAKE AND REAR BRAKE INSTALLING THE FRONT BRAKE MASTER CYLINDER 1. Install: • Brake master cylinder "1" • Brake master cylinder bracket "2" • Bolt (brake master cylinder bracket) "3" Bolt (brake master cylinder brack- et): 9 Nm (0.9 m•kg, 6.5 ft•lb) 4.

  • Page 170: Installing The Rear Brake Master Cylinder

    FRONT BRAKE AND REAR BRAKE INSTALLING THE REAR BRAKE MASTER CYLINDER 1. Install: • Copper washer "1" • Brake hose "2" • Union bolt "3" Union bolt: 30 Nm (3.0 m•kg, 22 ft•lb) 3. Install: Always use new copper washers. •...
  • Page 171 FRONT BRAKE AND REAR BRAKE INSTALLING THE FRONT BRAKE HOSE 1. Install: • Copper washer "1" • Brake hose "2" • Union bolt "3" Union bolt: 30 Nm (3.0 m•kg, 22 ft•lb) Always use new copper washers. 3. Pass the brake hose through the cable guide "1".
  • Page 172 FRONT BRAKE AND REAR BRAKE After installing the brake hose holders, make sure the brake hose does not contact the spring (rear shock absorber). If it does, correct its twist. INSTALLING THE REAR BRAKE HOSE 1. Install: • Copper washer "1" •...
  • Page 173 FRONT BRAKE AND REAR BRAKE Brake fluid may erode painted surfaces or After installation, while pulling the brake le- plastic parts. Always clean up spilled fluid ver in or pushing down on the brake pedal, immediately. check whether there is any brake fluid leak- ing where the union bolts are installed re- spectively at the brake master cylinder and brake caliper.

  • Page 174: Removing The Front Fork

    FRONT FORK FRONT FORK REMOVING THE FRONT FORK Order Part name Q'ty Remarks Hold the machine by placing the suit- Refer to "HANDLING NOTE". able stand under the engine. Refer to "FRONT WHEEL AND Front wheel REAR WHEEL" section. Refer to "FRONT BRAKE AND Front brake caliper REAR BRAKE"...
  • Page 175 FRONT FORK DISASSEMBLING THE FRONT FORK 30 Nm (3.0 m kg, 22 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 1 Nm (0.1 m kg, 0.7 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 55 Nm (5.5 m kg, 40 ft lb) Order Part name Q'ty...
  • Page 176 FRONT FORK HANDLING NOTE REMOVING THE ADJUSTER 1. Drain the outer tube of its front fork oil at its top. Support the machine securely so there is no 2. Loosen: danger of it falling over. • Adjuster "1" The front fork requires careful attention. So it is recommended that the front fork be maintained at the dealers.
  • Page 177 FRONT FORK 2. Remove: CHECKING THE DAMPER ASSEMBLY • Inner tube "1" 1. Inspect: • Damper assembly "1" Bend/damage → Replace. Oil seal removal steps: • O-ring "2" a. Push in slowly "a" the inner tube just before Wear/damage → Replace. it bottoms out and then pull it back quickly "b".
  • Page 178 FRONT FORK Inner tube bending limit: 0.2 mm (0.008 in) The bending value is shown by one half of the dial gauge reading. Do not attempt to straighten a bent inner tube as this may dangerously weaken the CHECKING THE COLLAR tube.
  • Page 179 FRONT FORK ASSEMBLING THE FRONT FORK 5. Measure: 1. Wash the all parts in a clean solvent. • Oil level (left and right) "a" 2. Stretch the damper assembly fully. Out of specification → Adjust. 3. Fill: Standard oil level "a": •...
  • Page 180 FRONT FORK 7. Loosen: Cap bolt wrench: • Compression damping adjuster "1" YM-01500/90890-01500 Cap bolt ring wrench: • Loosen the compression damping adjuster YM-01501/90890-01501 finger tight. • Record the set position of the adjuster (the amount of turning out the fully turned in posi- tion).
  • Page 181 FRONT FORK 13.Allow the overflowing oil to escape at the hole "a" in the damper assembly. The overflow measures about 8 cm (0.28 Imp oz, 0.27 US oz). 14.Check: • Damper assembly smooth movement Tightness/binding/rough spots → Repeat the steps 2 to 13. 16.Install: •...
  • Page 182 FRONT FORK 18.Install: 20.Install: • Slide metal "1" • Stopper ring "1" • Oil seal washer "2" To outer tube slot. Fit the stopper ring correctly in the groove in the outer tube. Press the slide metal into the outer tube with fork seal driver "3".
  • Page 183 FRONT FORK 23.Measure: • Distance "a" Out of specification → Turn into the locknut. Distance "a": 16 mm (0.63 in) or more Between the damper assembly "1" bottom and locknut "2" bottom. 26.Loosen: • Rebound damping adjuster "1" • Loosen the rebound damping adjuster finger tight.
  • Page 184 FRONT FORK 28.Inspect: • Gap "a" between the adjuster "1" and lock- nut "2". Out of specification → Retighten and read- just the locknut. Gap "a" between the adjuster and locknut: 0.5–1.0 mm (0.02–0.04 in) If the adjuster is installed out of specification, 31.Fill: proper damping force cannot be obtained.

  • Page 185: Installing The Front Fork

    FRONT FORK 32.Install: • Damper assembly "1" Use the cap bolt ring wrench "2" to tighten the To outer tube. damper assembly with specified torque. Temporarily tighten the damper assembly. Cap bolt ring wrench: YM-01501/90890-01501 33.Install: 3. Adjust: • Protector guide "1" •...
  • Page 186 FRONT FORK 4. Tighten: 6. Adjust: • Pinch bolt (upper bracket) "1" • Rebound damping force Pinch bolt (upper bracket): Turn in the damping adjuster "1" finger-tight 21 Nm (2.1 m•kg, 15 ft•lb) and then turn out to the originally set position. •...

  • Page 187: Removing The Handlebar

    HANDLEBAR HANDLEBAR REMOVING THE HANDLEBAR 0.5 Nm (0.05 m kg, 0.36 ft lb) 9 Nm (0.9 m kg, 6.5 ft lb) 28 Nm (2.8 m kg, 20 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 0.5 Nm (0.05 m kg, 0.36 ft lb) 40 Nm (4.0 m kg, 29 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb)
  • Page 188 HANDLEBAR DISASSEMBLING THE THROTTLE Order Part name Q'ty Remarks Grip cap (lower) Grip cap (upper) Grip assembly Grip (right) Refer to removal section. Tube guide 5-37...

  • Page 189: Removing The Brake Master Cylinder

    HANDLEBAR REMOVING THE BRAKE MASTER CYLINDER 1. Remove: • Brake master cylinder bracket "1" • Brake master cylinder "2" • Do not let the brake master cylinder hang on the brake hose. • Keep the brake master cylinder cap side horizontal to prevent air from coming in.

  • Page 190: Installing The Handlebar

    HANDLEBAR 2. Install: • Grip cap (upper) "1" • Grip cap (lower) "2" • Bolt (grip cap) "3" Temporarily tighten the bolts (grip cap). 2. Install: • Handlebar "1" • Handlebar upper holder "2" • Bolt (handlebar upper holder) "3" Bolt (handlebar upper holder): 28 Nm (2.8 m•kg, 20 ft•lb) INSTALLING THE HANDLEBAR...
  • Page 191 HANDLEBAR 5. Install: • Collar "1" • Grip cap cover "2" • Throttle grip "3" • Apply the lithium soap base grease on the throttle grip sliding surface. • Tighten the grip cap bolts temporarily without the throttle being fixed to the handlebar. 3.
  • Page 192 HANDLEBAR 7. Install: 11.Install: • Roller "1" • Brake master cylinder "1" • Collar "2" • Brake master cylinder bracket "2" • Bolt (brake master cylinder bracket) "3" • Apply the lithium soap base grease on the Bolt (brake master cylinder bracket): roller sliding surface and cable guide.
  • Page 193 HANDLEBAR 13.Install: 15.Adjust: • Engine stop switch "1" • Clutch lever free play • Clutch lever holder "2" Refer to "ADJUSTING THE CLUTCH LE- • Bolt (clutch lever holder) "3" VER FREE PLAY" section in the CHAPTER Bolt (clutch lever holder): 4 Nm (0.4 m•kg, 2.9 ft•lb) •...
  • Page 194 STEERING STEERING REMOVING THE STEERING Order Part name Q'ty Remarks TIGHTENING STEPS: • Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb) • Loosen it one turn. • Retighten it. 7 Nm (0.7 m•kg, 5.1 ft•lb) Hold the machine by placing the suit- Refer to "HANDLING NOTE".
  • Page 195 STEERING Order Part name Q'ty Remarks Steering ring nut Refer to removal section. Lower bracket Bearing race cover Upper bearing Lower bearing Refer to removal section. Bearing race Refer to removal section. 5-44...
  • Page 196 STEERING HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE STEERING RING NUT 1. Remove: • Steering ring nut "1" Use the steering nut wrench "2". Steering nut wrench: CHECKING THE STEERING STEM YU-33975/90890-01403 1.
  • Page 197 STEERING INSTALLING THE LOWER BRACKET 4. Install: 1. Install: • Steering ring nut "1" • Lower bearing "1" Steering ring nut: 7 Nm (0.7 m•kg, 5.1 ft•lb) Apply the lithium soap base grease on the dust Tighten the steering ring nut using the steer- seal lip and bearing inner circumference.
  • Page 198 STEERING 7. Install: 11.Tighten: • Front fork "1" • Pinch bolt (upper bracket) "1" • Upper bracket "2" Pinch bolt (upper bracket): 21 Nm (2.1 m•kg, 15 ft•lb) • Temporarily tighten the pinch bolts (lower • Pinch bolt (lower bracket) "2" bracket).

  • Page 199: Removing The Swingarm

    SWINGARM SWINGARM REMOVING THE SWINGARM Order Part name Q'ty Remarks Hold the machine by placing the suit- Refer to "HANDLING NOTE". able stand under the engine. Refer to "FRONT BRAKE AND Brake hose holder REAR BRAKE" section. Refer to "FRONT BRAKE AND Rear brake caliper REAR BRAKE"...

  • Page 200: Disassembling The Swingarm

    SWINGARM DISASSEMBLING THE SWINGARM 70 Nm (7.0 m kg, 50 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 6 Nm (0.6 m kg, 4.3 ft lb) 80 Nm (8.0 m kg, 58 ft lb) Order Part name Q'ty Remarks Refer to removal section.
  • Page 201 SWINGARM HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE CAP 1. Remove: • Left cap "1" Remove with a slotted-head screwdriver insert- CHECKING THE RELAY ARM ed under the mark "a" on the left cap. 1.
  • Page 202 SWINGARM INSTALLING THE BEARING AND OIL SEAL 1. Install: • Bearing "1" • Oil seal "2" To swingarm. • Apply the molybdenum disulfide grease on the bearing when installing. • Install the bearing by pressing it on the side having the manufacture's marks or numbers. •...

  • Page 203: Installing The Swingarm

    SWINGARM INSTALLING THE SWINGARM 1. Install: • Bushing "1" • Thrust bearing "2" • Oil seal "3" • Collar "4" To swingarm "5". Apply the molybdenum disulfide grease on the bushings, thrust bearings, oil seal lips and con- tact surfaces of the collar and thrust bearing. 4.
  • Page 204 SWINGARM 6. Install: • Swingarm "1" • Pivot shaft "2" Pivot shaft: 85 Nm (8.5 m•kg, 61 ft•lb) • Apply the molybdenum disulfide grease on the pivot shaft. • Insert the pivot shaft from right side. 9. Install: • Bolt (rear shock absorber-relay arm) "1" •...
  • Page 205 SWINGARM 11.Tighten: 14.Install: • Nut (relay arm) "1" • Drive chain support "1" • Drive chain support cover "2" Nut (relay arm): • Bolt {drive chain support [L = 50 mm (1.97 70 Nm (7.0 m•kg, 50 ft•lb) in)]} "3" •...

  • Page 206: Removing The Rear Shock Absorber

    REAR SHOCK ABSORBER REAR SHOCK ABSORBER REMOVING THE REAR SHOCK ABSORBER 56 Nm (5.6 m kg, 40 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 32 Nm (3.2 m kg, 23 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 53 Nm (5.3 m kg, 38 ft lb) Order Part name...
  • Page 207 REAR SHOCK ABSORBER 56 Nm (5.6 m kg, 40 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 32 Nm (3.2 m kg, 23 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 53 Nm (5.3 m kg, 38 ft lb) Order Part name Q'ty...

  • Page 208: Removing The Bearing

    • When scrapping the rear shock absorb- Remove the bearing by pressing its outer race. er, follow the instructions on disposal. NOTES ON DISPOSAL (YAMAHA DEALERS ONLY) Before disposing the rear shock absorber, be sure to extract the nitrogen gas from valve "1".

  • Page 209: Installing The Bearing

    REAR SHOCK ABSORBER 3. Remove: • Lower bearing "1" Remove the bearing by pressing its outer race. INSTALLING THE BEARING 1. Install: • Upper bearing "1" Install the bearing parallel until the stopper ring CHECKING THE REAR SHOCK ABSORBER groove appears by pressing its outer race. 1.

  • Page 210: Installing The Rear Shock Absorber

    REAR SHOCK ABSORBER 3. Install: 3. Tighten: • Lower bearing "1" • Adjuster "1" Install the bearing by pressing it on the side having the manufacture's marks or numbers. Installed depth of the bearing "a": 4 mm (0.16 in) 4. Adjust: •...
  • Page 211 REAR SHOCK ABSORBER 2. Install: • Bushing "1" • Collar "2" • Dust seal "3" • Apply the molybdenum disulfide grease on the bearing and dust seal lips. • Install the dust seals with their lips facing in- ward. 6. Install: •...
  • Page 212 This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowl- edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas- sembly, or reassembly only by reference to this manual.

  • Page 213: Electrical Components And Wiring Diagram

    ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS 1. Engine stop switch 4. CDI magneto 2. CDI unit 5. Spark plug 3. Ignition coil...

  • Page 214: Wiring Diagram

    ELECTRICAL COMPONENTS AND WIRING DIAGRAM WIRING DIAGRAM 1. Engine stop switch 2. CDI unit 3. Ignition coil 4. CDI magneto 5. Spark plug COLOR CODE Black Orange Yellow Black/Red B/W Black/White Green/Blue G/W Green/White White/Blue W/R White/Red...

  • Page 215: Ignition System

    IGNITION SYSTEM IGNITION SYSTEM INSPECTION STEPS Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure and for checking the spark plug which will not spark. Spark gap test Spark → *Clean or replace spark plug. No spark ↓...

  • Page 216: Spark Gap Test

    IGNITION SYSTEM SPARK GAP TEST CHECKING THE COUPLERS AND LEADS 1. Disconnect the spark plug cap from spark CONNECTION plug. 1. Check: 2. Connect the dynamic spark tester "1" (igni- • Couplers and leads connection tion checker "2") as shown. Rust/dust/looseness/short-circuit →...

  • Page 217: Checking The Ignition Coil

    IGNITION SYSTEM CHECKING THE IGNITION COIL 1. Inspect: • Primary coil resistance Out of specification → Replace. Tester (+) lead → Yellow lead "1" Tester (-) lead → Black lead "2" Primary coil re- Tester selector sistance position 0.24–0.36 Ω at 20 Ω...

  • Page 218: Checking The Cdi Unit

    IGNITION SYSTEM CHECKING THE CDI MAGNETO 1. Inspect: • Pickup coil resistance Out of specification → Replace. Tester (+) lead → White/Red lead "1" Tester (-) lead → White/Blue lead "2" Pickup coil resis- Tester selector tance position 248–372 Ω at 20 Ω...

  • Page 219: Tuning

    ENGINE TUNING • Lower atmospheric pressure (at a high alti- tude) reduces the density of the air. ENGINE TEST RUN CARBURETOR SETTING After warming up the engine equipped with the • The role of fuel is to cool the engine, and in standard type carburetor(s) and spark plug(s), the case of a 2-stroke engine, to lubricate the run two or three laps of the circuit and check the...
  • Page 220 ENGINE EFFECT OF SETTING PARTS IN RELATION ADJUSTING THE PILOT AIR SCREW TO THROTTLE VALVE OPENING The richness of the air-fuel mixture with full closed to 1/4 throttle can be set by turning the pilot air screw "1". Turning in the pilot air screw will enrich the mixture at low speeds, and turn- ing out it will lean out the mixture.
  • Page 221 ENGINE ADJUSTING THE JET NEEDLE GROOVE ADJUSTING THE JET NEEDLE POSITION On the carburetors used in the YZ125, the main Should the engine be hard to run smoothly at nozzle is a non disassembly type, so it can not intermediate speeds, the jet needle "1" must be be replaced.

  • Page 222: Carburetor Setting Parts

    ENGINE RELATIONSHIP WITH THROTTLE OPENING CARBURETOR SETTING PARTS The flow of the fuel through the carburetor main Part name Size Part number system is controlled by the main jet and then, it Main jet "1" Rich #470 137-14143-94 is further regulated by the area between the main nozzle and the jet needle.
  • Page 223 ENGINE Part name Size Part number Rich 6BFY43 284-14116-J2 6BFY43 284-14116-J3 (STD) 6BFY43 284-14116-J4 6BFY43 284-14116-J5 Lean 6BFY43 284-14116-J6 Rich 6BFY42 284-14116-H2 6BFY42 284-14116-H3 6BFY42 284-14116-H4 6BFY42 284-14116-H5 Lean 6BFY42 284-14116-H6 * For USA and CDN ** Except for USA and CDN...
  • Page 224 ENGINE ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING General condition Sandy condition Under 10°C 15–25°C Over 30°C Under 10°C 15–25°C Over 30°C (50°F) (59–77°F) (86°F) (50°F) (59–77°F) (86°F) (Winter) (Spring, Au- (Summer) (Winter) (Spring, Au- (Summer) tumn) tumn) Main jet #440 #430 #420...
  • Page 225 ENGINE EXAMPLES OF CARBURETOR SETTING DEPENDING ON SYMPTOM Symptom Setting Checking At full throttle Increase main jet calibration no. Discoloration of spark plug → If tan Stall at high speeds (Gradually) color, it is in good condition. *Hard breathing If cannot be corrected: Shearing noise Clogged float valve seat Whitish spark plug...
  • Page 226 ENGINE Symptom Setting Checking Poor response when Check overall settings. Check air filter for fouling. throttle is opened quickly Use main jet having lower calibra- tion no. Raise jet needle clip position. (1 groove up) If no effect, reverse the above pro- cedures.
  • Page 227 ENGINE CHANGE OF THE HEAT RANGE OF SPARK PLUGS Judging from the discoloration of spark plugs, if they are found improper, it can be corrected by the following two methods; changing carburetor settings and changing the heat range of spark plug.

  • Page 228: Selection Of The Secondary Reduction Ratio (Sprocket)

    CHASSIS CHASSIS DRIVE AND REAR WHEEL SPROCKETS SETTING PARTS SELECTION OF THE SECONDARY REDUCTION RATIO (SPROCKET) Part name Size Part number Drive sprocket "1" Secondary reduction ratio = Number of rear wheel sprocket teeth/Number of (STD) 9383B-13218 drive sprocket teeth Rear wheel sprocket "2"...

  • Page 229: Front Fork Setting

    CHASSIS Extent of adjustment: 100–120 kPa (1.0–1.2 kgf/cm 15–18 psi) FRONT FORK SETTING The front fork setting should be made depend- ing on the rider's feeling of an actual run and the circuit conditions. The front fork setting includes the following three factors: 1.

  • Page 230: Front Fork Setting Parts

    CHASSIS REAR SUSPENSION SETTING The rear suspension setting should be made Generally a stiff spring gives a stiff riding feel- depending on the rider's feeling of an actual run ing. Rebound damping tends to become weak- and the circuit conditions. er, resulting in lack of a sense of contact with The rear suspension setting includes the fol- the road surface or in a vibrating handlebar.
  • Page 231 CHASSIS Length "a" of standard shock: • If the machine is new and after it is broken in, 490 mm (19.29 in) the same set length of the spring may change because of the initial fatigue, etc. of the spring. Therefore, be sure to make reevalua- tion.
  • Page 232 CHASSIS [Unequal-pitch steel spring] • Extent of adjustment (spring preload) SPRING SPRING SPRING PART I.D. MARK/ PART TYPE RATE Maximum Minimum NUMBER Q'TY NUMBER (approx.) (-22212-) (-22212-) SOFT 5UN-A0 Green/2 1C3-00 5UN-B0 Red/2 1C3-10 5UN-C0 Black/2 1C3-20 5UN-D0 Blue/2 1C3-30 Position in 5UN-E0 Yellow/2...

  • Page 233: Suspension Setting (Front Fork)

    CHASSIS SUSPENSION SETTING (FRONT FORK) • If any of the following symptoms is experienced with the standard position as the base, make reset- ting by reference to the adjustment procedure given in the same chart. • Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm (3.5–3.9 in).

  • Page 234: Suspension Setting (Rear Shock Absorber)

    CHASSIS SUSPENSION SETTING (REAR SHOCK ABSORBER) • If any of the following symptoms is experienced with the standard position as the base, make reset- ting by reference to the adjustment procedure given in the same chart. • Adjust the rebound damping in 2-click increments or decrements. •...
  • Page 235 For your best ownership experience, think Genuine Yamaha! Genuine Yamaha Parts – Genuine Yamaha replacement parts are the exact same parts as the ones originally equipped on your vehicle, providing you with the performance and durability you have come to expect.
  • Page 236 PRINTED ON RECYCLED PAPER PRINTED IN JAPAN 2012.08–0.5 × 1 !

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