Yamaha YZ125N1 Service Manual
  1. Manuals
  2. Brands
  3. Yamaha Manuals
  4. Motorcycle
  5. YZ125N1
  6. Service manual
Yamaha YZ125N1 Service Manual

Yamaha YZ125N1 Service Manual

Yz series
Hide thumbs Also See for YZ125N1:
Table of Contents

Advertisement

Quick Links

See also: Owner's Service Manual
OWNER'S SERVICE MANUAL
YZ125N1
LIT-11626-14-36
5MV-28199-10

Advertisement

Table of Contents
loading

Related Manuals for Yamaha YZ125N1

Summary of Contents for Yamaha YZ125N1

  • Page 1 OWNER’S SERVICE MANUAL YZ125N1 LIT-11626-14-36 5MV-28199-10...
  • Page 3 EC010000 YZ125N1 OWNER’S SERVICE MANUAL ©2000 by Yamaha Motor Corporation, U.S.A. 1st Edition, June 2000 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-11626-14-36...
  • Page 4 EC020000 INTRODUCTION Congratulations on your purchase of a Yamaha YZ series. This model is the culmination of Yamaha’s vast experience in the production of pacesetting racing machines. It represents the highest grade of craftsmanship and reliability that have made Yamaha a leader.
  • Page 5 This list is compiled from the purchase registrations sent to Yamaha Motor Cor- Will the warranty be void or canceled if I do not operate or maintain my new YZ or WR exactly as poration, U.S.A.

  • Page 6: Important Notice

    EC040001 IMPORTANT NOTICE THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED COURSE. It is illegal for this machine to be op- erated on any public street, road, or highway. Off-road use on public lands may also be illegal. Please check local regulations before riding.
  • Page 7 5. GASOLINE IS HIGHLY FLAMMABLE. Always turn off the engine while refuel- ing. Take care to not spill any gasoline on the engine or exhaust system. Never refuel in the vicinity of an open flame, or while smoking. 6. GASOLINE CAN CAUSE INJURY. If you should swallow some gasoline, inhale excess gasoline vapors, or allow any gasoline to get into your eyes,...
  • Page 8 Some data in this manual may become out- dated due to improvements made to this model in the future. If there is any question you have regarding this manual or your machine, please consult your Yamaha dealer. EC070001 F.I.M. MACHINE WEIGHTS:...

  • Page 9: Specifications

    EC080000 HOW TO USE THIS MANUAL EC081000 PARTICULARLY IMPORTANT IN FORMATION The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY IS IN- VOLVED! Failure to follow WARNING instructions could re- sult in severe injury or death to the machine op- erator, a bystander, or a person inspecting or re- pairing the machine.
  • Page 10 EC083000 MANUAL FORMAT All of the procedures in this manual are organized in a sequential, step-by-step format. The informa- tion has been complied to provide the mechanic with an easy to read, handy reference that contains comprehensive explanations of all disassembly, repair, assembly, and inspection operations. In this revised format, the condition of a faulty component will precede an arrow symbol and the course of action required will follow the symbol, e.g., 9Bearings...
  • Page 11 EC085002 ILLUSTRATED SYMBOLS (Refer to the illustration) SPEC INFO Illustrated symbols 1 to 7 are designed as thumb tabs to indicate the chapter’s number and content. General information INSP Specifications Regular inspection and adjustments Engine Chassis Electrical Tuning CHAS ELEC Illustrated symbols 8 to r are used to identify the specifications appearing in the text.
  • Page 12 EC090000 INDEX GENERAL INFORMATION INFO SPECIFICATIONS SPEC REGULAR INSPECTION AND INSP ADJUSTMENTS ENGINE CHASSIS CHAS ELECTRICAL ELEC TUNING...

  • Page 13: Table Of Contents

    EC0A0000 CONTENTS CHAPTER 1 GENERAL INFORMATION DESCRIPTION ..........1-1 MACHINE IDENTIFICATION ......1-2 IMPORTANT INFORMATION .....1-3 CHECKING OF CONNECTION ....1-6 SPECIAL TOOLS........1-7 CONTROL FUNCTIONS......1-9 FUEL AND ENGINE MIXING OIL.....1-12 STARTING AND BREAK-IN .....1-13 TORQUE-CHECK POINTS.......1-16 CLEANING AND STORAGE ....1-17 CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS ....2-1 MAINTENANCE SPECIFICATIONS ...2-3 GENERAL TORQUE SPECIFICATIONS..2-12...

  • Page 14: Table Of Contents

    CHAPTER 4 ENGINE SEAT, FUEL TANK AND SIDE COVERS .............4-1 EXHAUST PIPE AND SILENCER ....4-3 RADIATOR..........4-4 CARBURETOR AND REED VALVE...4-7 CYLINDER HEAD , CYLINDER AND PISTON .............4-17 CLUTCH AND PRIMARY DRIVEN GEAR ............4-30 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR......4-38 YPVS GOVERNOR ........4-46 WATER PUMP ..........4-49 CDI MAGNETO .........4-53...
  • Page 15 CHAPTER 6 ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ........6-1 IGNITION SYSTEM........6-2 CHAPTER 7 TUNING ENGINE............7-1 CHASSIS...........7-13...

  • Page 16: Description

    DESCRIPTION INFO EC100000 GENERAL INFORMATION EC110000 NOTE: DESCRIPTION 9The machine you have purchased may differ 1 Clutch lever 2 ”ENGINE STOP” button slightly from those shown in the following. 3 Front brake lever 9Designs and specifications are subject to 4 Throttle grip change without notice.

  • Page 17: Machine Identification

    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: Important Information

    IMPORTANT INFORMATION INFO EC130000 IMPORTANT INFORMATION EC131010 PREPARATION FOR REMOVAL AND DISASSEMBLY 1. Remove all dirt, mud, dust, and foreign ma- terial before removal and disassembly. When washing the machine with high pres- sured water, cover the parts as follows. 9Silencer end 9Air filter intake slit 9Crankcase cover hole at the bottom...
  • Page 19 IMPORTANT INFORMATION INFO EC132000 ALL REPLACEMENT PARTS 1. We recommend to use Yamaha genuine parts for all replacements. Use oil and/or grease recommended by Yamaha for as- sembly and adjustment. EC133000 GASKETS, OIL SEALS AND O-RINGS 1. All gaskets, oil seals, and O-rings should be replaced when an engine is overhauled.
  • Page 20 IMPORTANT INFORMATION INFO EC136000 CIRCLIPS 1. All circlips should be inspected carefully be- fore reassembly. Always replace piston pin clips after one use. Replace distorted cir- clips. When installing a circlip 1, make sure that the sharp-edged corner 2 is positioned opposite to the thrust 3 it receives.

  • Page 21: Checking Of Connection

    CHECKING OF CONNECTION INFO EC1C0001 CHECKING OF CONNECTION Dealing with stains, rust, moisture, etc. on the connector. 1. Disconnect: 9Connector 2. Dry each terminal with an air blower. 3. Connect and disconnect the connector two or three times. 4. Pull the lead to check that it will not come off.

  • Page 22: Special Tools

    SPECIAL TOOLS INFO EC140001 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 provid- ed.
  • Page 23 Dynamic spark tester YM-34487 90890-06754 90890-06754 Ignition checker This instrument is necessary for checking the igni- tion system components. ACC-QUICK-GS-KT Quick gasket ® ACC-QUICK-GS-KT 90890-85505 90890-85505 YAMAHA Bond No. 1215 This sealant (Bond) is used for crankcase mating surface, etc.

  • Page 24: Control Functions

    CONTROL FUNCTIONS INFO EC150000 CONTROL FUNCTIONS EC151000 “ENGINE STOP” BUTTON The “ENGINE STOP” button 1 is located on the left handlebar. Continue pushing the “ENGINE STOP” button till the engine comes to a stop. EC152000 CLUTCH LEVER The clutch lever 1 is located on the left handle- bar;...
  • Page 25 CONTROL FUNCTIONS INFO EC156000 FRONT BRAKE LEVER The front brake lever 1 is located on the right handlebar. Pull it toward the handlebar to acti- vate the front brake. EC157000 REAR BRAKE PEDAL The rear brake pedal 1 is located on the right side of the machine.
  • Page 26 CONTROL FUNCTIONS INFO EC15F000 VALVE JOINT This valve joint 1 prevents fuel from flowing out and is installed to the fuel tank breather hose. In this installation, make sure the arrow faces the fuel tank and also downward. EC15R001 DETACHABLE SIDESTAND This sidestand 1 is used to support only the machine when standing or transporting it.

  • Page 27: Fuel And Engine Mixing Oil

    FUEL AND ENGINE MIXING OIL INFO EC160050 FUEL AND ENGINE MIXING OIL Mix oil with the gas at the ratio specified below. Always use fresh, name-brand gasoline, and mix the oil and gas the day of the race. Do not use premix that is more than a few hours old.

  • Page 28: Starting And Break-In

    STARTING AND BREAK-IN INFO EC190000 STARTING AND BREAK-IN Before starting the machine, perform the checks in the pre-operation check list. Never start or run the engine in a closed area. The exhaust fumes are poisonous; they can cause loss of consciousness and death in a very short time.
  • Page 29 STARTING AND BREAK-IN INFO EC194001 BREAK-IN PROCEDURES 1. Before starting the engine, fill the fuel tank with a break-in oil-fuel mixture as follows. Mixing oil: Mixing ratio: Yamalube “2-R” 15:1 2. Perform the pre-operation checks on the machine. 3. Start and warm up the engine. Check the idle speed, and check the operation of the controls and the “ENGINE STOP”...
  • Page 30 STARTING AND BREAK-IN INFO 9After the break-in or before each race, you must check the entire machine for loose fit- tings and fasteners as per “TORQUE- CHECK POINTS”. Tighten all such fasteners as required. 9When any of the following parts have been replaced, they must be broken in.

  • Page 31: Torque-Check Points

    TORQUE-CHECK POINTS INFO EC1A0012 TORQUE-CHECK POINTS Frame construction Frame to rear frame Combined seat and tank Fuel tank to frame Engine mounting Frame to engine Steering Steering shaft to Steering shaft to frame handlebar Steering shaft to handle crown Handle crown to handlebar Suspension Front Steering shaft to...

  • Page 32: Cleaning And Storage

    CLEANING AND STORAGE INFO EC1B0000 CLEANING AND STORAGE EC1B1000 CLEANING Frequent cleaning of your machine will enhance its appearance, maintain good overall perfor- mance, and extend the life of many components. 1. Before washing the machine, block off the end of the exhaust pipe to prevent water from entering.
  • Page 33 CLEANING AND STORAGE INFO EC1B2001 STORAGE If your machine is to be stored for 60 days or more, some preventive measures must be taken to avoid deterioration. After cleaning the ma- chine thoroughly, prepare it for storage as fol- lows: 1.

  • Page 34: General Specifications

    SPEC GENERAL SPECIFICATIONS EC200000 SPECIFICATIONS EC211000 GENERAL SPECIFICATIONS Model name: YZ125LC (EUROPE) YZ125N1 (USA) YZ125(N) (CDN, AUS, NZ, ZA) Model code number: 5MV1 (USA, CDN, ZA) 5MV2 (EUROPE) 5MV4 (AUS, NZ) Dimensions: USA, CDN, ZA EUROPE AUS, NZ Overall length...
  • Page 35 SPEC GENERAL SPECIFICATIONS Carburetor: χ 38SS/MIKUNI Type/Manufacturer Spark plug: Type/Manufacturer BR9EG/NGK 0.5~0.6 mm (0.020~0.024 in) Clutch type: Wet, multiple-disc Transmission: Primary reduction system Gear Primary reduction ratio 64/19 (3.368) Secondary reduction system Chain drive Secondary reduction ratio 48/13 (3.692) Transmission type Constant mesh, 6-speed Operation Left foot operation...

  • Page 36: Maintenance Specifications

    SPEC MAINTENANCE SPECIFICATIONS EC212000 MAINTENANCE SPECIFICATIONS EC212100 ENGINE Item Standard Limit Cylinder head: … Combustion chamber capacity 10.2 cm (0.359 Imp oz, 0.345 US oz) … Warp limit 0.03 mm (0.0012 in) Cylinder: Bore size 54.000~54.014 mm 54.1 mm (2.130 in) (2.1260~2.1265 in) …...
  • Page 37 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Transmission: … Main axle deflection limit 0.01 mm (0.0004 in) … Drive axle deflection limit 0.01 mm (0.0004 in) Shifter: … Shifting type Cam drum and guide bar … Guide bar bending limit 0.05 mm (0.0020 in) …...
  • Page 38 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb M14 × 1.25 Spark plug M 8 × 1.25 Cylinder head (nut) M 8 × 1.25 (stud) M 8 × 1.25 Cylinder (nut) M10 × 1.25 (stud) Power valve: M 5 ×...
  • Page 39 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb M 6 × 1.0 Exhaust pipe M 6 × 1.0 Exhaust pipe stay (front) M 6 × 1.0 Exhaust pipe stay (rear) M 6 × 1.0 Silencer (front) M 6 ×...
  • Page 40 SPEC MAINTENANCE SPECIFICATIONS EC212201 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 460 mm (18.1 in) 455 mm (17.9 in) …...
  • Page 41 SPEC MAINTENANCE SPECIFICATIONS Item Standard Limit Wheel: … Front wheel type Spoke wheel … Rear wheel type Spoke wheel 21 × 1.60/Aluminum … Front rim size/Material 19 × 1.85/Aluminum … Rear rim size/Material Rim runout limit: … Radial 2.0 mm (0.08 in) Lateral …...
  • Page 42 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb M 8 × 1.25 Handle crown and outer tube M 8 × 1.25 Under bracket and outer tube M24 × 1.0 Handle crown and steering shaft 14.5 M 8 ×...
  • Page 43 SPEC MAINTENANCE SPECIFICATIONS Tightening torque Part to be tightened Thread size Q'ty m•kg ft•lb M 6 × 1.0 Rear brake master cylinder and frame M 6 × 1.0 Rear brake reservoir tank and frame M10 × 1.25 Rear brake hose union bolt (caliper) M10 ×...
  • Page 44 32°/3000 r/min … 0.52 mm (0.020 in) … Advancer type Electrical CDI: … Magneto-model/Manufacturer F4SS00/YAMAHA 720~1,080 Ω at 20°C (68°F) … Source coil 1 resistance (color) (Green/White-Black/Red) 44~66 Ω at 20°C (68°F) … Source coil 2 resistance (color) (Black-Green/Blue) 248~372 Ω at 20°C (68°F) …...

  • Page 45: General Torque Specifications

    GENERAL TORQUE SPECIFICATIONS/ SPEC DEFINITION OF UNITS EC220001 GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard faste- ners with standard I.S.O. pitch threads. Torque specifications for special components or assem- blies are included in the applicable sections of this book. To avoid warpage, tighten multi-faste- ner assemblies in a crisscross fashion, in pro- gressive stages, until full torque is reached.

  • Page 46: Cable Routing Diagram

    SPEC CABLE ROUTING DIAGRAM EC240000 CABLE ROUTING DIAGRAM C Clamp the throttle cable and 1 Brake hose hose inside the YPVS 2 Fuel tank breather hose “ENGINE STOP” button lead breather hose. H Clamp the radiater breather 3 Cable guide to the frame.
  • Page 47 SPEC CABLE ROUTING DIAGRAM B If the brake hose contacts I Pass the clutch cable over 1 Brake hose holder 2 Master cylinder the spring (rear shock the radiator hose. J Clamp the wireharness on 3 Brake hose absorber), correct its twist. C Install the brake hose so that 4 Hose guide the top of the CDI unit with...
  • Page 48 SPEC CABLE ROUTING DIAGRAM A Install the brake hose so that its pipe portion 1 Brake hose 2 Master cylinder directs as show and lightly touches the 3 “ENGINE STOP” button lead projection on the master cylinder. B Pass the “ENGINE STOP” button lead in 4 “ENGINE STOP”...

  • Page 49: Maintenance Intervals

    If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer. After...
  • Page 50 Replace bearing TIRE, WHEELS Inspect air pressure, wheel run-out, tire wear and spoke looseness Retighten sprocket bolt Inspect bearings Replace bearings Lubricate Lithium base grease THROTTLE, CONTROL CABLE Yamaha cable lube or Check routing and connection SAE 10W-30 motor oil Lubricate...

  • Page 51: Pre-Operation Inspection And Maintenance

    INSP PRE-OPERATION INSPECTION AND MAINTENANCE EC320000 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. EC321000 GENERAL INSPECTION AND MAINTENANCE Item Routine Page...

  • Page 52: Engine

    ENGINE/COOLANT LEVEL INSPECTION/ INSP COOLANT REPLACEMENT EC350000 ENGINE EC351011 COOLANT LEVEL INSPECTION Do not remove the radiator cap 1 1 , drain bolt and hoses when the engine and radia- tor are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury.
  • Page 53 INSP COOLANT REPLACEMENT Take care so that coolant does not splash on painted surfaces. If it splashes, wash it away with water. 1. Place a container under the engine. 2. Remove: 9Coolant drain bolt 1 3. Remove: 9Radiator cap Drain the coolant completely. 4.
  • Page 54 INSP RADIATOR CAP INSPECTION 9 Do not mix more than one type of ethyl- ene glycol antifreeze containing corro- sion inhibitors for aluminum engine. 9 Do not use water containing impurities or oil. Handling notes of coolant: The coolant is harmful so it should be handled with special care.
  • Page 55 RADIATOR CAP OPENING PRESSURE INSPECTION/ INSP COOLING SYSTEM INSPECTION EC356002 RADIATOR CAP OPENING PRESSURE INSPECTION 1. Attach: 9Radiator cap tester 1 and adapter 2 Radiator cap tester: YU-24460-01/90890-01325 Adapter: YU-33984/90890-01352 NOTE: Apply water on the radiator cap seal. 3 Radiator cap 2.
  • Page 56 INSP CLUTCH ADJUSTMENT NOTE: 9 Do not apply pressure more than specified pressure. 9 Radiator should be filled fully. 4. Inspect: 9Pressure Impossible to maintain the specified pres- sure for 10 seconds Repair. 9Radiator 1 9Radiator hose joint 2 Coolant leakage Repair or replace.
  • Page 57 THROTTLE CABLE ADJUSTMENT/ INSP THROTTLE LUBRICATION EC35A001 THROTTLE CABLE ADJUSTMENT 1. Check: 9Throttle grip free play a Out of specification Adjust. Throttle grip free play a a : 3~5 mm (0.12~0.20 in) 2. Adjust: 9Throttle grip free play Throttle grip free play adjustment steps: 9Loosen the locknut 1.
  • Page 58 INSP AIR FILTER CLEANING 3. Install: 9Throttle cable cap 1 Nm (0.1 m•kg, 0.7 ft•lb) 9Cap cover EC35G040 AIR FILTER CLEANING NOTE: Proper air filter maintenance is the biggest key to preventing premature engine wear and dam- age. Never run the engine without the air filter element in place;...
  • Page 59 INSP TRANSMISSION OIL LEVEL CHECK 3. Inspect: 9Air filter element Damage Replace. 4. Apply: 9Foam-air-filter oil or engine mixing oil To the element. NOTE: Squeeze out the excess oil. Element should be wet but not dripping. 5. Install: 9Filter guide 1 NOTE: Align the projection a on filter guide with the hole b in air filter element.
  • Page 60 INSP TRANSMISSION OIL REPLACEMENT 3. Check: 9Transmission oil level Transmission oil level checking steps: 9Remove the oil check bolt 1. 9Inspect the oil level. NOTE: Be sure the machine is positioned straight up when inspecting the oil level. Never attempt to remove the oil check bolt just after high speed operation.
  • Page 61 INSP PILOT AIR SCREW ADJUSTMENT 4. Remove: 9Oil drain bolt 1 9Oil filler cap 2 Drain the transmission oil. 5. Install: 9Aluminum washer 9Oil drain bolt 1 20 Nm (2.0 m•kg, 14 ft•lb) 6. Fill: 9Transmission oil Recommended oil: Yamalube 4 (10W-30) or SAE 10W-30 type SE motor oil Oil capacity (periodic oil change):...
  • Page 62 IDLE SPEED ADJUSTMENT/MUFFLER INSPECTION/ INSP SILENCER FIBER REPLACEMENT EC35M010 IDLE SPEED ADJUSTMENT 1. Start the engine and thoroughly warm it up. 2. Adjust: 9 Idle speed Adjustment steps: 9Loosen the locknut 1. 9Turn the throttle stop screw 2 until the en- gine runs at the lowest possible speed.

  • Page 63: Silencer Fiber Replacement

    Fully apply Quick gasket ® (Yamaha bond No. 1215) or equivalent as shown. Quick gasket ® ACC-QUICK-GS-KT Yamaha bond No. 1215: 90890-85505 5. Install: 9Bolt (fiber) 1 10 Nm (1.0 m•kg, 7.2 ft•lb) 9Silencer 2 9Bolt [silencer (front)] 3 12 Nm (1.2 m•kg, 8.7 ft•lb) 9Bolt [silencer (rear)] 4 7 Nm (0.7 m•kg, 5.1 ft•lb)

  • Page 64: Chassis

    INSP CHASSIS/BRAKE SYSTEM AIR BLEEDING EC360000 CHASSIS EC361012 BRAKE SYSTEM AIR BLEEDING Bleed the brake system if: 9 The system has been disassembled. 9 A brake hose has been loosened or removed. 9 The brake fluid is very low. 9 The brake operation is faulty. A dangerous loss of braking performance may occur if the brake system is not properly bleed.
  • Page 65 INSP FRONT BRAKE ADJUSTMENT NOTE: If bleeding is difficult, it may be necessary to let the brake fluid system stabilize for a few hours. Repeat the bleeding procedure when the tiny bubbles in the system have disappeared. j. Add brake fluid to the level line on the reservoir.

  • Page 66: Rear Brake Adjustment

    REAR BRAKE ADJUSTMENT/ INSP FRONT BRAKE PAD INSPECTION AND REPLACEMENT EC364002 REAR BRAKE ADJUSTMENT 1. Check: 9 Brake pedal height a Out of specification Adjust. Brake pedal height a a : 5 mm (0.20 in) 2. Adjust: 9 Brake pedal height Pedal height adjustment steps: 9 Loosen the locknut 1.
  • Page 67 INSP FRONT BRAKE PAD INSPECTION AND REPLACEMENT 9Loosen the pad pin 2. 9Remove the brake hose holder 3 and caliper 4 from the front fork. 9Remove the pad pin and brake pads 5. 9Connect the transparent hose 6 to the bleed screw 7 and place the suitable con- tainer under its end.
  • Page 68 INSP REAR BRAKE PAD INSPECTION AND REPLACEMENT 9Install the pad pin plug Pad pin plug: 3 Nm (0.3 m•kg, 2.2 ft•lb) 3. Inspect: 9Brake fluid level Refer “BRAKE FLUID LEVEL INSPECTION” section. 4. Check: 9Brake lever operation A softy or spongy feeling Bleed brake system.
  • Page 69 INSP REAR BRAKE PAD INSPECTION AND REPLACEMENT 9Remove the pad pin 6 and brake pads 7. 9Connect the transparent hose 8 to the bleed screw 9 and place the suitable con- tainer under its end. 9Loosen the bleed screw and push the caliper piston in.
  • Page 70 REAR BRAKE PAD INSULATOR INSPECTION INSP BRAKE FLUID LEVEL INSPECTION EC36b000 REAR BRAKE PAD INSULATOR INSPECTION 1. Remove: 9Brake pad Refer to “REAR BRAKE PAD INSPEC- TION AND REPLACEMENT” section. 2. Inspect: 9Rear brake pad insulator 1 Damage Replace. EC367001 BRAKE FLUID LEVEL INSPECTION 1.
  • Page 71 INSP SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION EC368000 SPROCKETS INSPECTION 1. Inspect: 9Sprocket teeth a Excessive wear Replace. NOTE: Replace the drive, driven sprockets and drive chain as a set. EC369002 DRIVE CHAIN INSPECTION 1. Remove: 9Master link clip 9Joint 1 9Drive chain 2 2.
  • Page 72 INSP DRIVE CHAIN SLACK ADJUSTMENT 5. Install: 9Drive chain 1 9Joint 2 9Master link clip 3 Be sure to install the master link clip to the direction as shown. a Turning direction 6. Lubricate: 9Drive chain Drive chain lubricant: SAE 10W-30 motor oil or suitable chain lubricants EC36A060 DRIVE CHAIN SLACK ADJUSTMENT...
  • Page 73 INSP FRONT FORK INSPECTION 3. Adjust: 9Drive chain slack Drive chain slack adjustment steps: 9Loosen the axle nut 1 and locknuts 2. 9Adjust chain slack turning adjusters 3. 3 3 counter- To tighten Turn adjuster clockwise. Turn adjuster 3 3 clockwise To loosen and push wheel forward.
  • Page 74 FRONT FORK OIL SEAL AND DUST SEAL CLEANING/ INSP FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT EC36D001 FRONT FORK OIL SEAL AND DUST SEAL CLEANING 1. Remove: 9Protector 9Dust seal 1 NOTE: Use a thin screw driver, and be careful not to damage the inner fork tube and dust seal.
  • Page 75 FRONT FORK COMPRESSION DAMPING FORCE INSP ADJUSTMENT Do not force the adjuster past the minimum or maximum extent of adjustment. The ad- juster may be damaged. Always adjust each front fork to the same setting. Uneven adjustment can cause poor handling and loss of stability. EC36J001 FRONT FORK COMPRESSION DAMPING FORCE ADJUSTMENT...
  • Page 76 INSP REAR SHOCK ABSORBER INSPECTION 9STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position. Standard position: 14 clicks out *12 clicks out *For EUROPE Do not force the adjuster past the minimum or maximum extent of adjustment.
  • Page 77 REAR SHOCK ABSORBER SPRING PRELOAD INSP ADJUSTMENT EC36M013 REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT 1. Elevate the rear wheel by placing the suit- able stand under the engine. 2. Remove: 9Rear frame 3. Loosen: 9Locknut 1 4. Adjust: 9Spring preload By turning the adjuster 2.
  • Page 78 REAR SHOCK ABSORBER REBOUND DAMPING INSP FORCE ADJUSTMENT EC36N014 REAR SHOCK ABSORBER REBOUND DAMPING FORCE ADJUSTMENT 1. Adjust: 9Rebound damping force By turning the adjuster 1. Stiffer Increase the rebound damping force. (Turn the adjuster 1 1 in.) Softer b b Decrease rebound damping force.
  • Page 79 REAR SHOCK ABSORBER LOW COMPRESSION INSP DAMPING FORCE ADJUSTMENT EC36c000 REAR SHOCK ABSORBER LOW COMPRESSION DAMPING FORCE ADJUSTMENT 1. Adjust: 9Low compression damping force By turning the adjuster 1. Stiffer a a Increase the low compression damping force. (Turn the ad- juster 1 1 in.) Softer b b Decrease the low compres-...
  • Page 80 REAR SHOCK ABSORBER LOW COMPRESSION INSP DAMPING FORCE ADJUSTMENT EC36d000 REAR SHOCK ABSORBER HIGH COMPRESSION DAMPING FORCE ADJUSTMENT 1. Adjust: 9High compression damping force By turning the adjuster 1. Stiffer a a Increase the high compression damping force. (Turn the ad- juster 1 1 in.) Softer b b Decrease the high compres-...
  • Page 81 TIRE PRESSURE CHECK/SPOKES INSPECTION AND INSP TIGHTENING/WHEEL INSPECTION EC36Q000 TIRE PRESSURE CHECK 1. Measure: 9Tire pressure Out of specification Adjust. Standard tire pressure: 100 kPa (1.0 kg/cm , 15 psi) NOTE: 9Check the tire while it is cold. 9Loose bead stoppers allow the tire to slip off its position on the rim when the tire pressure is low.
  • Page 82 INSP STEERING HEAD INSPECTION AND ADJUSTMENT 2. Inspect: 9Bearing free play Exist play Replace. EC36U013 STEERING HEAD INSPECTION AND ADJUSTMENT 1. Elevate the front wheel by placing a suitable stand under the engine. 2. Check: 9Steering shaft Grasp the bottom of the forks and gently rock the fork assembly back and forth.
  • Page 83 INSP STEERING HEAD INSPECTION AND ADJUSTMENT Ring nut wrench: YU-33975/90890-01403 Ring nut (initial tightening): 38 Nm (3.8 m•kg, 27ft•lb) 9Loosen the ring nut one turn. 9Retighten the ring nut using the ring nut wrench. Avoid over-tightening. Ring nut (final tightening): 7 Nm (0.7 m•kg, 5.1 ft•lb) 9Check the steering shaft by turning it lock to lock.
  • Page 84 INSP LUBRICATION EC36a042 LUBRICATION Å Use Yamaha cable lube or equivalent on To ensure smooth operation of all components, these areas. lubricate your machine during setup, after break- ı Use SAE10W-30 motor oil or suitable chain in, and after every race.

  • Page 85: Electrical

    INSP ELECTRICAL/SPARK PLUG INSPECTION EC370000 ELECTRICAL EC371001 SPARK PLUG INSPECTION 1. Remove: 9Spark plug 2. Inspect: 9Electrode 1 Wear/Damage Replace. 9Insulator color 2 Normal condition is a medium to light tan color. Distinctly different color Check the engine condition. NOTE: When the engine runs for many hours at low speeds, the spark plug insulator will become sooty, even if the engine and carburetor are in...
  • Page 86 INSP IGNITION TIMING CHECK EC372051 IGNITION TIMING CHECK 1. Remove: 9Cylinder head Refer to “CYLINDER HEAD, CYLINDER AND PISTON” section in the CHAPTER 4. 9Crankcase cover (left) 2. Attach: 9Dial gauge 1 9Dial gauge stand 2 Dial gauge: YU-3097/90890-01252 Stand: YU-1256 3.
  • Page 87 INSP IGNITION TIMING CHECK 7. Adjust: 9Ignition timing Adjustment steps: 9Loosen the screws (stator) 1. 9Align the punch mark on the rotor with punch mark on the stator 2 by moving the stator. 9Tighten the screws (stator). Screw (stator): 8 Nm (0.8 m•kg, 5.8 ft•lb) 3-40...

  • Page 88: Covers

    SEAT, FUEL TANK AND SIDE COVERS EC400000 ENGINE EC4R0000 SEAT, FUEL TANK AND SIDE COVERS 7 Nm (0.7 m•kg, 5.1 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb)
  • Page 89 SEAT, FUEL TANK AND SIDE COVERS EC4R3000 REMOVAL POINTS EC413101 Side cover 1. Remove: 9 Side cover (left and right) 1 Be sure to remove the seat before remov- ing the side cover. If you remove the side cover with force without removing the seat, 2 2 (on the inside) may contact the panel the air cleaner case and come off.

  • Page 90: Exhaust Pipe And Silencer

    EXHAUST PIPE AND SILENCER EC4S0000 EXHAUST PIPE AND SILENCER 7 Nm (0.7 m•kg, 5.1 ft•lb) 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) 1 Silencer removal 2 Exhaust pipe removal Extent of removal: Extent of removal...

  • Page 91: Radiator

    RADIATOR EC450001 RADIATOR 1 Nm (0.1 m•kg, 0.7 ft•lb) 1 Nm (0.1 m•kg, 0.7 ft•lb) 1 Radiator removal Extent of removal: Extent of removal Order Part name Q’ty Remarks RADIATOR REMOVAL Preparation for Drain the coolant. Refer to “COOLANT REPLACEMENT“ removal section in the CHAPTER 3.
  • Page 92 RADIATOR EC456000 HANDLING NOTE Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious in- jury. When the engine has cooled, open the ra- diator cap by the following procedure: Place a thick rag, like a towel, over the radiator cap, slowly rotate the cap counter-...
  • Page 93 RADIATOR EC455000 ASSEMBLY AND INSTALLATION EC445341 Radiator 1. Install: 9Radiator breather hose 1 9Radiator hose 3 2 1 Nm (0.1 m•kg, 0.7 ft•lb) 9Radiator hose 1 3 1 Nm (0.1 m•kg, 0.7 ft•lb) To radiator (right) 4. NOTE: Install the radiator hose 3 with its shorter pro- truding length a from the protector 5 on the ra- diator side.

  • Page 94: Carburetor And Reed Valve

    CARBURETOR AND REED VALVE EC460000 CARBURETOR AND REED VALVE 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Nm (0.1 m•kg, 0.7 ft•lb) 1 Carburetor removal 2 Reed valve removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CARBURETOR AND REED VALVE REMOVAL Preparation for Fuel tank...
  • Page 95 CARBURETOR AND REED VALVE EC468000 CARBURETOR DISASSEMBLY 1 Carburetor disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks CARBURETOR DISASSEMBLY Mixing chamber top Throttle valve Refer to “REMOVAL POINTS”. Needle holder Jet needle Float chamber Needle jet cover Float pin Float Valve seat...
  • Page 96 CARBURETOR AND REED VALVE EC466030 HANDLING NOTE Do not disassemble the venturi block 1 1 and main nozzle 2 2 because it will cause a drop in carburetor performance. EC463000 REMOVAL POINTS EC463110 Throttle valve 1. Remove: 9Throttle valve 1 9Ring 2 9Spring (throttle valve) 3 9Mixing chamber top 4...
  • Page 97 CARBURETOR AND REED VALVE 2. Inspect: 9Main jet 1 9Main jet holder 2 9Pilot jet 3 Contamination Clean. NOTE: 9Use a petroleum based solvent for cleaning. Blow out all passages and jets with com- pressed air. 9Never use a wire. EC464200 Needle valve 1.
  • Page 98 CARBURETOR AND REED VALVE EC464A00 Filter 1. Inspect: 9Filter 1 Damage Replace. NOTE: Inspect the filter as it is assembled to the carbu- retor. Do not remove the filter except when replacing it. EC464802 Fuel level 1. Measure: 9Fuel level a Out of specification Adjust.
  • Page 99 CARBURETOR AND REED VALVE EC464600 Float 1. Inspect: 9Float 1 Damage Replace. EC464701 Reed valve 1. Measure: 9Reed valve bending a Out of specification Replace. Reed valve bending limit: 0.2 mm (0.008 in) 9Valve stopper height b Out of specification Adjust stopper/ Replace valve stopper.
  • Page 100 CARBURETOR AND REED VALVE 2. Install: 9Reed valve assembly 1 9Reed valve spacer 2 NOTE: Install the reed valve spacer with its wider con- tact surface side a to the right. 3. Install: 9Carburetor joint 1 9Bolt (carburetor joint) 2 10 Nm (1.0 m•kg, 7.2 ft•lb) EC4652C2 Carburetor...
  • Page 101 CARBURETOR AND REED VALVE 3. Install: 9Main jet holder 1 9Main jet 2 9Pilot jet 3 9Valve seat 4 9Screw (valve seat) 5 4. Install: 9Needle valve 1 9Float 2 9Float pin 3 9Screw (float pin) 4 9Needle jet cover 5 NOTE: 9After installing the needle valve to the float, in- stall them to the carburetor.
  • Page 102 CARBURETOR AND REED VALVE 7. Install: 9Throttle cable 1 9Mixing chamber top 2 9Spring (throttle valve) 3 9Ring 4 9Throttle valve 5 NOTE: 9While compressing the spring, connect the throttle cable. 9Align the projection a on the ring with the groove b in the needle holder 6.
  • Page 103 CARBURETOR AND REED VALVE 2. Tighten: 9Screw (air filter joint) 1 9Screw (carburetor joint) 2 3. Clamp: 9Air vent hose 1 9Overflow hose 2 Refer to “CABLE ROUTING DIAGRAM” section in the CHAPTER 2. 4. Adjust: 9Idle speed Refer to “IDLE SPEED ADJUSTMENT” section in the CHAPTER 3.

  • Page 104: Cylinder Head , Cylinder And Piston

    CYLINDER HEAD, CYLINDER AND PISTON EC470000 CYLINDER HEAD, CYLINDER AND PISTON EC478000 CYLINDER HEAD AND CYLINDER 34 Nm (3.4 m•kg, 24 ft•lb) 20 Nm (2.0 m•kg, 14 ft•lb) 28 Nm (2.8 m•kg, 20 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 5 Nm (0.5 m•kg, 3.6 ft•lb) 5 Nm (0.5 m•kg, 3.6 ft•lb)
  • Page 105 CYLINDER HEAD, CYLINDER AND PISTON EC478100 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) 4 Nm (0.4 m•kg, 2.9 ft•lb) 1 Piston and piston ring removal 2 Power valve removal Extent of removal: Extent of removal...
  • Page 106 CYLINDER HEAD, CYLINDER AND PISTON EC473000 REMOVAL POINTS EC473210 Push rod 1. Remove: 9Bolt (push rod) 1 9Push rod 2 NOTE: Set the collar 3 included in owner’s tool kit to remove the bolt (push rod). EC473401 Piston and piston ring 1.
  • Page 107 CYLINDER HEAD, CYLINDER AND PISTON EC474000 INSPECTION EC474101 Cylinder head 1. Remove: 9Carbon deposits Use a rounded scraper 1. NOTE: Take care to avoid damaging the spark plug threads. Do not use a sharp instrument. Avoid scratching the aluminum. 2. Inspect: 9Cylinder head water jacket Crust of minerals/Rust Remove.
  • Page 108 CYLINDER HEAD, CYLINDER AND PISTON 2. Inspect: 9Cylinder inner surface Score marks Repair or replace. Use #400~600 grit wet sandpaper. Do not rebore the cylinder. 3. Measure: 9Cylinder bore “C” Use cylinder gauge 1. Out of limit Replace. NOTE: Measure the cylinder bore “C” in parallel (A, B, C) to and at right angles to the crankshaft (a, b).
  • Page 109 CYLINDER HEAD, CYLINDER AND PISTON EC474402 Piston pin and small end bearing 1. Inspect: 9Piston pin 9Small end bearing Signs of heat discoloration Replace. 2. Measure: 9Piston pin outside diameter Use micrometer 1. Out of limit Replace. Piston pin outside diameter: Standard <Limit>...
  • Page 110 CYLINDER HEAD, CYLINDER AND PISTON EC474502 Piston ring 1. Install: 9Piston ring Into the cylinder. Push the ring with the piston crown. 2. Measure: 9End gap Use a thickness gauge 1. Out of limit Replace. Ring end gap (installed): Standard <Limit>...
  • Page 111 CYLINDER HEAD, CYLINDER AND PISTON Piston clearance: Standard <Limit> 0.040~0.045 mm 0.1 mm (0.0016~0.0018 in) (0.004 in) EC474700 Combination of piston and cylinder 1. Check: 9Cylinder mark a Cylinder mark a a Cylinder size 54.000~54.002 mm (2.1260~2.1261 in) 54.004~54.006 mm (2.1261~2.1262 in) 54.008~54.010 mm (2.1263~2.1264 in)
  • Page 112 CYLINDER HEAD, CYLINDER AND PISTON EC474830 Power valve 1. Inspect: 9Power valve 1,2 1 Wear/Damage Replace. Carbon deposits Remove. 9Link lever 2 9Valve shaft 3 9Collar 4 Wear/Damage Replace. 9Spring 5 Broken Replace. EC474901 Power valve hole on cylinder 1. Remove: 9Carbon deposits From power valve hole surface a.
  • Page 113 CYLINDER HEAD, CYLINDER AND PISTON 2. Install: 9Spring 1 9Link lever 2 9Collar 3 9Valve shaft 4 9Bolt (link lever) 5 4 Nm (0.4 m•kg, 2.9 ft•lb) NOTE: 9Install the spring to the link lever, and then to the cylinder. 9Install the spring with its stopper portion a fac- ing inward.
  • Page 114 CYLINDER HEAD, CYLINDER AND PISTON EC475233 Piston ring and piston 1. Install: 9Piston ring 1 NOTE: 9Take care not to scratch the piston or damage the piston ring. 9Align the piston ring gap with the pin 2. 9After installing the piston ring, check the smooth movement of it.
  • Page 115 CYLINDER HEAD, CYLINDER AND PISTON EC4753A1 Cylinder head and cylinder 1. Apply: 9Engine oil To piston 1, piston ring 2 and cylinder surface. 2. Install: 9Cylinder 1 Make sure the piston ring is properly posi- tioned. Install the cylinder with one hand while compressing the piston ring with the other hand.
  • Page 116 CYLINDER HEAD, CYLINDER AND PISTON 5. Install: 9Gasket (power valve housing) 9Power valve housing 1 9Bolt (power valve housing) 2 5 Nm (0.5 m•kg, 3.6 ft•lb) 6. Install: 9O-ring 1 NOTE: Apply the lithium soap base grease on the O- rings.

  • Page 117: Clutch And Primary Driven Gear

    CLUTCH AND PRIMARY DRIVEN GEAR EC490000 CLUTCH AND PRIMARY DRIVEN GEAR EC498000 CLUTCH PLATE AND FRICTION PLATE 10 Nm (1.0 m•kg, 7.2 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Clutch plate and friction plate removal Extent of removal: Extent of removal Order Part name Q’ty...
  • Page 118 CLUTCH AND PRIMARY DRIVEN GEAR EC498100 PRIMARY DRIVEN GEAR 80 Nm (8.0 m•kg, 58 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 1 Primary driven gear removal 2 Push lever removal Extent of removal: Extent of removal Order Part name Q’ty Remarks PRIMARY DRIVEN GEAR REMOVAL...
  • Page 119 CLUTCH AND PRIMARY DRIVEN GEAR EC493000 å å REMOVAL POINTS EC483211 Clutch boss 1. Remove: 9Nut 1 9Lock washer 2 9Clutch boss 3 NOTE: Straighten the lock washer tab and use the clutch holding tool 4, 5 to hold the clutch boss. ∫...
  • Page 120 CLUTCH AND PRIMARY DRIVEN GEAR EC484500 Friction plate 1. Measure: 9Friction plate thickness Out of specification Replace friction plate as a set. Measure at all four points. Friction plate thickness: Standard <Limit> 2.9~3.1 mm 2.8 mm (0.114~0.122 in) (0.110 in) EC484600 Clutch plate 1.
  • Page 121 CLUTCH AND PRIMARY DRIVEN GEAR EC495000 ASSEMBLY AND INSTALLATION EC495240 Clutch 1. Install: 9Thrust plate [ φ 36 mm (1.42 in)] 1 9Spacer 2 9Bearing 3 9Primary driven gear 4 NOTE: Apply the transmission oil on the spacer, bearing and primary driven gear inner circumference. 2.
  • Page 122 CLUTCH AND PRIMARY DRIVEN GEAR 5. Install: 9Friction plate 1 1 9Clutch plate 2 9Friction plate 2 3 NOTE: 9Install the clutch plates and friction plates alter- nately on the clutch boss, starting with a friction plate and ending with a friction plate. 9Use the friction plates 1 for the first and final while paying attention to the difference in sur- face pattern.
  • Page 123 CLUTCH AND PRIMARY DRIVEN GEAR 9. Install: 9Gasket (clutch cover) 1 NOTE: Position the rack a on the push rod backward. 10. Install: 9Clutch cover 1 9Bolt (clutch cover) 2 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE: Tighten the bolts in stage, using a crisscross pattern.
  • Page 124 CLUTCH AND PRIMARY DRIVEN GEAR 4. Install: 9Plain washer 1 9Circlip 2 4-37...

  • Page 125: Kick Axle, Shift Shaft And Primary Drive Gear

    KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C0000 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C8000 PRIMARY DRIVE GEAR 10 Nm (1.0 m•kg, 7.2 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 55 Nm (5.5 m•kg, 40 ft•lb) 1 Primary drive gear removal Extent of removal: Extent of removal Order...
  • Page 126 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C8100 KICK AXLE AND SHIFT SHAFT 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) 1 Kick axle and kick idle gear removal Extent of removal: 2 Shift shaft and stopper lever removal Extent of removal...
  • Page 127 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C3000 REMOVAL POINTS EC483111 Primary drive gear 1. Loosen: 9Bolt (primary drive gear) 1 NOTE: Place an aluminum plate a between the teeth of the primary drive gear 2 and driven gear 3. EC4B3101 Kick axle assembly 1.
  • Page 128 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4B4300 Kick gear clip 1. Measure: 9Kick clip friction force Out of specification Replace. Use a spring gauge 1. Kick clip friction force: 0.8~1.2 kg (1.8~2.6 lb) EC4B4400 Shift shaft 1. Inspect: 9Shift shaft 1 Bend/Damage Replace.
  • Page 129 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR EC4C5000 ASSEMBLY AND INSTALLATION EC4C5120 Stopper lever 1. Install: 9Torsion spring 1 9Stopper lever 2 9Spacer 3 9Bolt (stopper lever) 4 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE: 9Align the stopper lever roller with the slot on segment.
  • Page 130 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR 4. Install: 9Bolt (shift guide) 1 10 Nm (1.0 m•kg, 7.2 ft•lb) EC4C5301 Shift shaft 1. Install: 9Roller 1 9Shift shaft 2 NOTE: Apply the transmission oil on the roller and shift shaft.
  • Page 131 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR 4. Hook: 9Torsion spring 1 NOTE: Turn the torsion spring clockwise and hook into the proper hole a in the crankcase. EC4C5402 Kick idle gear 1. Install: 9Circlip 1 9Kick idle gear 2 9Plain washer 3 NOTE: 9Apply the transmission oil on the kick idle gear...
  • Page 132 KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAR 5. Install: 9Crankcase cover (right) 1 NOTE: 9Position the rack a on the push rod backward. 9Mesh the governor gear 2, and impeller shaft gear 3 with primary drive gear 4. 6. Install: 9Bolt [crankcase cover (right)] 1 10 Nm (1.0 m•kg, 7.2 ft•lb) NOTE:...

  • Page 133: Ypvs Governor

    YPVS GOVERNOR EC4K0000 YPVS GOVERNOR 5 Nm (0.5 m•kg, 3.6 ft•lb) 1 YPVS governor removal and disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks YPVS GOVERNOR REMOVAL Preparation for Crankcase cover (right) Refer to “KICK AXLE, SHIFT SHAFT AND removal PRIMARY DRIVE GEAR”...
  • Page 134 YPVS GOVERNOR EC4K3000 REMOVAL POINTS EC4K3100 Governor 1. Remove: 9Dowel pin 1 NOTE: While compressing the spring, remove the dowel pin. EC4K4000 INSPECTION EC4K4100 Governor groove 1. Inspect: 9Plain washer 1 9Collar 2 Wear/Damage Replace. EC4K4200 Bearing 1. Inspect: 9Thrust bearing 1 9Plain washer 2 Wear/Damage Replace.
  • Page 135 YPVS GOVERNOR 2. Install: 9Ball 1 9Retainer 2 To governor shaft 3. NOTE: Apply the transmission oil on the retainer and ball. 3. Install: 9Dowel pin 1 NOTE: 9While compressing the spring, install the dowel pin. 9Make sure the dowel pin fits into the groove a in the retainer.

  • Page 136: Water Pump

    WATER PUMP EC4G0000 WATER PUMP 14 Nm (1.4 m•kg, 10 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Impeller shaft removal 2 Oil seal removal Extent of removal: Extent of removal Order Part name Q’ty Remarks WATER PUMP DISASSEMBLY...
  • Page 137 WATER PUMP EC4G3000 REMOVAL POINTS EC4G3110 Impeller shaft 1. Remove: 9Impeller 1 9Plain washer 2 9Impeller shaft 3 NOTE: Hold the impeller shaft on its width across the flats a with spanners, etc. and remove the im- peller. EC4G3210 Oil seal NOTE: It is not necessary to disassemble the water pump, unless there is an abnormality such as...
  • Page 138 WATER PUMP EC444300 Impeller shaft gear 1. Inspect: 9Gear teeth a Wear/Damage Replace. EC4H4600 Bearing 1. Inspect: 9Bearing 1 Rotate inner race with a finger. Rough spot/Seizure Replace. EC444400 Oil seal 1. Inspect: 9Oil seal 1 Wear/Damage Replace. EC4G5000 ASSEMBLY AND INSTALLATION EC4G5111 Oil seal 1.
  • Page 139 WATER PUMP EC4G5220 Impeller shaft 1. Install: 9Impeller shaft 1 NOTE: 9Take care so that the oil seal lip is not dam- aged or the spring does not slip off its position. 9When installing the impeller shaft, apply the lithium soap base grease on the oil seal lip and impeller shaft.

  • Page 140: Cdi Magneto

    CDI MAGNETO EC4L0000 CDI MAGNETO 8 Nm (0.8 m•kg, 5.8 ft•lb) 33 Nm (3.3 m•kg, 24 ft•lb) 5 Nm (0.5 m•kg, 3.6 ft•lb) 1 CDI magneto removal Extent of removal: Extent of removal Order Part name Q’ty Remarks CDI MAGNETO REMOVAL Preparation for Seat and fuel tank Refer to “SEAT, FUEL TANK AND...
  • Page 141 CDI MAGNETO EC4L3000 REMOVAL POINTS EC4L3102 Rotor 1. Remove: 9Nut (rotor) 1 9Plain washer 2 Use the rotor holding tool 3. Rotor holding tool: YU-1235/90890-01235 2. Remove: 9Rotor 1 Use the flywheel puller 2. Flywheel puller: YM-1189/90890-01189 NOTE: When installing the flywheel puller, turn it coun- terclockwise.
  • Page 142 CDI MAGNETO 2. Install: 9Woodruff key 1 9Rotor 2 NOTE: 9Clean the tapered portions of the crankshaft and rotor. 9When installing the woodruff key, make sure that its flat surface a is in parallel with the crankshaft center line b. 9When installing the rotor, align the keyway c of the rotor with the woodruff key.
  • Page 143 CDI MAGNETO 7. Connect: 9CDI magneto lead 1 Refer to “CABLE ROUTING DIAGRAM” section in the CHAPTER 2. 8. Install: 9Gasket [crankcase cover (left)] 8. Install: 9Crankcase cover (left) 1 9Gasket [crankcase cover (left)] 9Screw [crankcase cover (left)] 2 9Crankcase cover (left) 1 5 Nm (0.5 m•kg, 3.6 ft•lb) 9Screw [crankcase cover (left)] 2 NOTE:...

  • Page 144: Engine Removal

    ENGINE REMOVAL EC4M0000 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) 69 Nm (6.9 m•kg, 50 ft•lb) 69 Nm (6.9 m•kg, 50 ft•lb) 85 Nm (8.5 m•kg, 61 ft•lb) 60 Nm (6.0 m•kg, 43 ft•lb) Extent of removal Order Part name...
  • Page 145 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) 69 Nm (6.9 m•kg, 50 ft•lb) 69 Nm (6.9 m•kg, 50 ft•lb) 85 Nm (8.5 m•kg, 61 ft•lb) 60 Nm (6.0 m•kg, 43 ft•lb) 1 Engine removal Extent of removal: Extent of removal...
  • Page 146 ENGINE REMOVAL EC4M3000 REMOVAL POINTS EC4F3100 Drive sprocket 1. Remove: 9Nut (drive sprocket) 1 9Lock washer 2 NOTE: 9Straighten the lock washer tab. 9Loosen the nut while applying the rear brake. 2. Remove: 9Drive sprocket 1 9Drive chain 2 NOTE: Remove the drive sprocket together with the dri- ve chain.
  • Page 147 ENGINE REMOVAL EC4M5000 ASSEMBLY AND INSTALLATION EC4M5171 Engine installation 1. Install: 9Engine 1 Install the engine from right side. 9Pivot shaft 2 85 Nm (8.5 m•kg, 61 ft•lb) 9Engine mounting bolt (lower) 3 69 Nm (6.9 m•kg, 50 ft•lb) 9Engine mounting bolt (front) 4 69 Nm (6.9 m•kg, 50 ft•lb) 9Engine bracket 5 9Bolt (engine bracket) 6...
  • Page 148 ENGINE REMOVAL 2. Install: 9Lock washer 1 9Nut (drive sprocket) 2 60 Nm (6.0 m•kg, 43 ft•lb) NOTE: Tighten the nut while applying the rear brake. 3. Bend the lock washer tab to lock the nut. 4. Install: 9Chain cover 1 9Screw (chain cover) 2 5 Nm (0.5 m•kg, 3.6 ft•lb) 4-61...

  • Page 149: Crankcase And Crankshaft

    CRANKCASE AND CRANKSHAFT EC4N0000 30 Nm (3.0 m•kg, 22 ft•lb) 14 Nm (1.4 m•kg, 10 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 20 Nm (2.0 m•kg, 14 ft•lb) 1 Crankcase separation 2 Crankshaft removal Extent of removal: 3 Crankshaft bearing removal Extent of removal Order Part name...
  • Page 150 CRANKCASE AND CRANKSHAFT EC4N3000 REMOVAL POINTS EC4N3100 Segment 1. Remove: 9 Bolt (segment) 1 9 Segment 2 NOTE: Turn the segment counterclockwise until it stops and loosen the bolt. EC4N3211 Crankcase 1. Remove: 9Crankcase (right) 1 Use the crankcase separating tool 2 and crankcase separating bolt 3.
  • Page 151 CRANKCASE AND CRANKSHAFT EC4N3301 Crankshaft 1. Remove: 9Crankshaft 1 Use the crankcase separating tool 2 and crankcase separating bolt 3. Crankcase separating tool: YU-1135-A/90890-01135 Crankcase separating bolt: YM-1305/90890-01305 Do not use a hammer to drive out the crankshaft. EC4N3401 Crankshaft bearing 1.
  • Page 152 CRANKCASE AND CRANKSHAFT 2. Inspect: 9Bearings 1 Rotate inner race with a finger. Rough spot/Seizure Replace. 3. Inspect: 9Oil seal 1 Damage Replace. EC4N4202 Crankshaft 1. Measure: 9Runout limit a 9Small end free play limit b 9Connecting rod big end side clearance c 9Crank width d Out of specification Replace.
  • Page 153 CRANKCASE AND CRANKSHAFT EC4N5102 Oil seal 1. Install: 9Oil seal (left) 1 9Oil seal (right) 2 NOTE: 9Apply the lithium soap base grease on the oil seal lip. 9Install the oil seal with its manufacture’s marks or numbers facing outward. EC4N5272 Crankshaft 1.
  • Page 154 Unsmooth operation Repair. 3. Apply: 9Sealant On the crankcase (right) 1 ® Quick gasket ACC-QUICK-GS-KT Yamaha bond No. 1215: 90890-85505 NOTE: Clean the contacting surface of crankcase (left and right) before applying the sealant. 4. Install: 9Dowel pin 1 9O-ring 2 9Crankcase (right) 3 To crankcase (left) 4.
  • Page 155 CRANKCASE AND CRANKSHAFT 6. Install: 9Holder 1 9Bolt (holder) 2 10 Nm (1.0 m•kg, 7.2 ft•lb) 7. Install: 9Segment 1 9Bolt (segment) 2 30 Nm (3.0 m•kg, 22 ft•lb) NOTE: 9 When installing the segment onto the shift cam 3, align the punch mark a with the dowel pin 9 Turn the segment clockwise until it stops and tighten the bolt.

  • Page 156: Transmission, Shift Cam And Shift Fork

    TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H0000 10 Nm (1.0 m•kg, 7.2 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 1 Shift cam and shift fork removal 2 Main axle and drive axle removal Extent of removal: Extent of removal Order Part name Q’ty Remarks...
  • Page 157 TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H3000 REMOVAL POINTS EC4H3200 Transmission 1. Remove: 9Main axle 1 9Drive axle 2 NOTE: 9Tap lightly on the transmission drive axle with a soft hammer to remove. 9Remove assembly carefully. Note the position of each part. Pay particular attention to the lo- cation and direction of shift forks.
  • Page 158 TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H4801 Shift fork, shift cam and segment 1. Inspect: 9Shift fork 1 Wear/Damage/Scratches Replace. 2. Inspect: 9Shift cam 1 9Segment 2 9Guide bar 3 Bend/Wear/Damage Replace. 3. Check: 9Shift fork movement On its guide bar. Unsmooth operation Replace shift fork and/or guide bar.
  • Page 159 TRANSMISSION, SHIFT CAM AND SHIFT FORK 2. Install: 92nd wheel gear (28T) 1 96th wheel gear (24T) 2 94th wheel gear (27T) 3 93rd wheel gear (26T) 4 95th wheel gear (26T) 5 91st wheel gear (30T) 6 To drive axle 7. NOTE: 9Apply the molybdenum disulfide oil on the 1st, 2nd, 3rd and 4th wheel gears inner circumfer-...
  • Page 160 TRANSMISSION, SHIFT CAM AND SHIFT FORK EC4H5331 Shift cam and shift fork 1. Install: 9Shift fork 1 (L) 1 9Shift fork 2 2 9Shift fork 3 (R) 3 NOTE: 9Mesh the shift fork #1 (L) with the 6th wheel gear 4 and #3 (R) with the 5th wheel gear 6 on the drive axle.

  • Page 161: Front Wheel And Rear Wheel

    CHAS FRONT WHEEL AND REAR WHEEL EC500000 CHASSIS EC590000 FRONT WHEEL AND REAR WHEEL EC598000 FRONT WHEEL 23 Nm (2.3 m•kg, 17 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 23 Nm (2.3 m•kg, 17 ft•lb) 105 Nm (10.5 m•kg, 75 ft•lb) 16 Nm (1.6 m•kg, 11 ft•lb) 7 Nm (0.7 m•kg, 5.1 ft•lb) 12 Nm (1.2 m•kg, 8.7 ft•lb)
  • Page 162 CHAS FRONT WHEEL AND REAR WHEEL EC598100 REAR WHEEL 14 Nm (1.4 m•kg, 10 ft•lb) 125 Nm (12.5 m•kg, 90 ft•lb) 42 Nm (4.2 m•kg, 30 ft•lb) 1 Rear wheel removal 2 Wheel bearing removal 3 Brake disc removal Extent of removal: Extent of removal Order Part name...
  • Page 163 CHAS FRONT WHEEL AND REAR WHEEL EC593000 REMOVAL POINTS EC523101 Rear wheel 1. Remove: 9Wheel 1 NOTE: Push the wheel forward and remove the drive chain 2. EC513201 Wheel bearing (if necessary) 1. Remove: 9Bearing 1 NOTE: Remove the bearing using a general bearing puller 2.
  • Page 164 CHAS FRONT WHEEL AND REAR WHEEL EC514200 Wheel axle 1. Measure: 9Wheel axle bends Out of specification Replace. Use the dial gauge 1. Wheel axle bending limit: 0.5 mm (0.020 in) NOTE: The bending value is shown by one half of the dial gauge reading.
  • Page 165 CHAS FRONT WHEEL AND REAR WHEEL EC595000 ASSEMBLY AND INSTALLATION EC595101 Front wheel 1. Install: 9Bearing (left) 1 9Spacer 2 9Bearing (right) 3 9Oil seal 4 NOTE: 9 Apply the lithium soap base grease on the bearing and oil seal lip when installing. 9 Use a socket that matches the outside diam- eter of the race of the bearing.
  • Page 166 CHAS FRONT WHEEL AND REAR WHEEL 5. Install: 9Wheel axle 1 NOTE: Apply the lithium soap base grease on the wheel axle. 6. Install: 9Nut (wheel axle) 1 105 Nm (10.5 m•kg, 75 ft•lb) 7. Tighten: 9Bolt (axle holder) 1 23 Nm (2.3 m•kg, 17 ft•lb) NOTE: Before tightening the bolt, fit the wheel axle to...
  • Page 167 CHAS FRONT WHEEL AND REAR WHEEL 9. Install: 9Hose cover 1 9Plain washer 2 9Bolt [hose cover (M8)] 3 16 Nm (1.6 m•kg, 11 ft•lb) 9Bolt [hose cover (M6)] 4 7 Nm (0.7 m•kg, 5.1 ft•lb) EC5251A0 Rear wheel 1. Install: 9Bearing (right) 1 9Circlip 2 9Spacer 3...
  • Page 168 CHAS FRONT WHEEL AND REAR WHEEL 3. Install: 9Driven sprocket 1 9Bolt (driven sprocket) 2 9Plain washer (driven sprocket) 3 9Nut (driven sprocket) 4 42 Nm (4.2 m•kg, 30 ft•lb) NOTE: Tighten the nuts in stage, using a crisscross pat- tern.
  • Page 169 CHAS FRONT WHEEL AND REAR WHEEL 8. Install: 9Chain puller (right) 1 9Plain washer 2 9Nut (wheel axle) 3 NOTE: Temporarily tighten the nut (wheel axle) at this point. 9. Adjust: 9Drive chain slack a Drive chain slack : 40~50 mm (1.6~2.0 in) Refer to “DRIVE CHAIN SLACK ADJUSTMENT”...

  • Page 170: Front Brake And Rear Brake

    CHAS FRONT BRAKE AND REAR BRAKE EC5A0000 FRONT BRAKE AND REAR BRAKE EC5A8000 FRONT BRAKE 9 Nm (0.9 m•kg, 6.5 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) 23 Nm (2.3 m•kg, 17 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb)

  • Page 171: Rear Brake

    CHAS FRONT BRAKE AND REAR BRAKE EC5A8100 REAR BRAKE 7 Nm (0.7 m•kg, 5.1 ft•lb) 4 Nm (0.4 m•kg, 2.9 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 10 Nm (1.0 m•kg, 7.2 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 26 Nm (2.6 m•kg, 19 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 1 Caliper removal...
  • Page 172 CHAS FRONT BRAKE AND REAR BRAKE EC5A8200 CALIPER DISASSEMBLY 3 Nm (0.3 m•kg, 2.2 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 6 Nm (0.6 m•kg, 4.3 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 3 Nm (0.3 m•kg, 2.2 ft•lb) A Front B Rear 1 Front caliper disassembly...
  • Page 173 CHAS FRONT BRAKE AND REAR BRAKE EC5A8300 MASTER CYLINDER DISASSEMBLY 2 Nm (0.2 m•kg, 1.4 ft•lb) A Front B Rear 1 Front master cylinder disassembly 2 Rear master cylinder disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks MASTER CYLINDER DISASSEMBLY Master cylinder cap...
  • Page 174 CHAS FRONT BRAKE AND REAR BRAKE EC5A3000 REMOVAL POINTS EC5A3100 Brake fluid 1. Remove: [Front] 9Master cylinder cap 1 [Rear] 9Reservoir tank cap 1 9Protector NOTE: Do not remove the diaphragm. A Front B Rear 2. Connect the transparent hose 1 to the bleed screw 2 and place a suitable contain- er under its end.
  • Page 175 CHAS FRONT BRAKE AND REAR BRAKE EC533402 Piston seal kit 1. Remove: 9Dust seal 1 9Piston seal 2 NOTE: Remove the piston seals and dust seals by pushing them with a finger. Never attempt to pry out piston seals and dust seals.
  • Page 176 CHAS FRONT BRAKE AND REAR BRAKE EC534214 Caliper 1. Inspect: 9Caliper cylinder inner surface a Wear/Score marks Replace caliper as- sembly. A Front B Rear 2. Inspect: 9Caliper piston 1 Wear/Score marks Replace caliper piston assembly. Replace the piston seals and dust seals 2 2 whenever a caliper is disassembled.
  • Page 177 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9Piston seal 1 9Dust seal 2 Always use new piston seals and dust seals. NOTE: Fit the piston seals and dust seals onto the slot on caliper correctly. A Front B Rear 3.
  • Page 178 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9Copper washer 1 9Union bolt 2 30 Nm (3.0 m•kg, 22 ft•lb) Always use new copper washers. Install the brake hose so that its pipe por- tion a a directs as show and lightly touches the projection b b on the caliper.
  • Page 179 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9Disc cover 1 9Bolt (disc cover) 2 7 Nm (0.7 m•kg, 5.1 ft•lb) 3. Install: 9Copper washer 1 9Brake hose 2 9Union bolt 3 30 Nm (3.0 m•kg, 22 ft•lb) Always use new copper washers. Install the brake hose to the caliper with the paint a a on the pipe facing the caliper and with the pipe contacting the caliper...
  • Page 180 CHAS FRONT BRAKE AND REAR BRAKE EC5A5220 Master cylinder kit 1. Clean: 9Master cylinder 9Master cylinder kit Clean them with brake fluid. 2. Install: 9Master cylinder cup (primary) 1 9Master cylinder cup (secondary) 2 To master cylinder piston 3. NOTE: Apply the brake fluid on the master cylinder cup.
  • Page 181 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: [Front] 9Master cylinder kit 1 9Plain washer 2 9Circlip 3 9Master cylinder boot 4 To master cylinder 5. [Rear] 9Master cylinder kit 1 9Push rod 2 9Circlip 3 9Master cylinder boot 4 To master cylinder 5.
  • Page 182 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9Brake lever 1 9Bolt (brake lever) 2 6 Nm (0.6 m•kg, 4.3 ft•lb) 9Nut (brake lever) 3 6 Nm (0.6 m•kg, 4.3 ft•lb) NOTE: Apply the lithium soap base grease on the brake lever sliding surface, bolt and contacting surface of the master cylinder piston.
  • Page 183 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: 9Pin 1 9Plain washer 2 9Cotter pin 3 NOTE: After installing, check the brake pedal height. Refer to “REAR BRAKE ADJUSTMENT” section in the CHAPTER 3. EC5A5911 Front brake hose 1. Install: 9Brake hose 1 10 Nm (1.0 m•kg, 7.2 ft•lb) To brake hose holder 2.
  • Page 184 CHAS FRONT BRAKE AND REAR BRAKE 4. Install: 9Copper washer 1 9Brake hose 2 9Union bolt 3 30 Nm (3.0 m•kg, 22 ft•lb) Always use new copper washers. Install the brake hose so that its pipe por- tion a a directs as show and lightly touches the projection b b on the master cylinder.
  • Page 185 CHAS FRONT BRAKE AND REAR BRAKE 2. Install: 9Brake hose holder 1 9Screw (brake hose holder) 2 4 Nm (0.4 m•kg, 2.9 ft•lb) 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.
  • Page 186 CHAS FRONT BRAKE AND REAR BRAKE 2. Air bleed: 9Brake system Refer to “BRAKE SYSTEM AIR BLEED- ING” section in the CHAPTER 3. 3. Inspect: 9Brake fluid level Fluid at lower level Fill up. Refer to “BRAKE FLUID LEVEL INSPEC- TION”...

  • Page 187: Front Fork

    CHAS FRONT FORK EC550000 4 Nm (0.4 m•kg, 2.9 ft•lb) 20 Nm (2.0 m•kg, 14 ft•lb) 23 Nm (2.3 m•kg, 17 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) 1 Front fork removal Extent of removal: Extent of removal...

  • Page 188: Front Fork

    CHAS FRONT FORK EC558000 FRONT FORK DISASSEMBLY 29 Nm (2.9 m•kg, 21 ft•lb) 1 Nm (0.1 m•kg, 0.7 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 55 Nm (5.5 m•kg, 40 ft•lb) 1 Oil seal removal 2 Damper rod removal Extent of removal: Extent of removal Order Part name...
  • Page 189 CHAS FRONT FORK EC556000 HANDLING NOTE NOTE: The front fork requires careful attention. So it is recommended that the front fork be maintained at the dealers. To prevent an accidental explosion of air, the following instructions should be ob- served: 9 The front fork with a built-in piston rod has a very sophisticated internal con- struction and is particularly sensitive to...
  • Page 190 CHAS FRONT FORK EC553201 Inner tube 1. Remove: 9Dust seal 1 9Stopper ring 2 Using slotted-head screwdriver. Take care not to scratch the inner tube. 2. Remove: 9Inner tube 1 Oil seal removal steps: 9 Push in slowly a the inner tube just be- fore it bottoms out and then pull it back quickly b.
  • Page 191 CHAS FRONT FORK EC554200 Base valve 1. Inspect: 9Valve assembly 1 Wear/Damage Replace. 9O-ring 2 Damage Replace. EC554400 Fork spring 1. Measure: 9Fork spring free length a Out of specification Replace. Fork spring free length: Standard <Limit> 460 mm 455 mm (18.1 in) (17.9 in) EC554502...
  • Page 192 CHAS FRONT FORK EC554700 Cap bolt 1. Inspect: 9Cap bolt 1 9O-ring 2 9Air bleed screw 3 Wear/Damage Replace. EC555000 ASSEMBLY AND INSTALLATION EC5551A1 Front fork assembly 1. Wash the all parts in a clean solvent. 2. Install: 9Damper rod 1 To inner tube 2.
  • Page 193 CHAS FRONT FORK 5. Install: 9Spring guide 1 9Locknut 2 To damper rod 3. NOTE: 9Install the spring guide with its cut a facing up- ward. 9With its thread b facing upward, fully finger tighten the locknut onto the damper rod. 6.
  • Page 194 CHAS FRONT FORK 9. Install: 9Slide metal 1 9Plain washer 2 To outer tube slot. NOTE: Press the slide metal into the outer tube with fork seal driver 3. Fork seal driver: YM-01442/90890-01442 10. Install: 9Oil seal 1 NOTE: Press the oil seal into the outer tube with fork seal driver 2.
  • Page 195 CHAS FRONT FORK 13. Check: 9Inner tube smooth movement Tightness/Binding/Rough spots Repeat the steps 2 to 12. 14. Compress the front fork fully. 15. Fill: 9Front fork oil Until outer tube top surface with recom- mended fork oil 1. Recommended oil: Suspension oil “01”...
  • Page 196 CHAS FRONT FORK 19. Wait ten minutes until the air bubbles have been removed from the front fork, and the oil has dispense evenly in system before setting recommended oil level. NOTE: Fill with the fork oil up to the top end of the outer tube, or the fork oil will not spread over to every part of the front forks, thus making it impossible to obtain the correct level.
  • Page 197 CHAS FRONT FORK 21. Measure: 9Distance a Out of specification Turn into the locknut. Distance a a : 20 mm (0.79 in) or more Between damper rod 1 1 top and locknut 2 2 top. 22. Loosen: 9Rebound damping adjuster 1 NOTE: 9Loosen the rebound damping adjuster finger tight.
  • Page 198 CHAS FRONT FORK 26. Tighten: 9Cap bolt (locknut) 1 29 Nm (2.9 m•kg, 21 ft•lb) NOTE: 9While compressing the fork spring, set the thin type spanners 2 between the spacer 3 and spring guide 4. 9Hold the locknut 5 and tighten the cap bolt with specified torque.
  • Page 199 CHAS FRONT FORK 4. Tighten: 9Pinch bolt (handle crown) 1 23 Nm (2.3 m•kg, 17 ft•lb) 9Pinch bolt (under bracket) 2 20 Nm (2.0 m•kg, 14 ft•lb) Tighten the under bracket to specified torque. If torqued too much, it may cause the front fork to malfunction.

  • Page 200: Handlebar

    CHAS HANDLEBAR EC5B0000 1 Nm (0.1 m•kg, 0.7 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) 2 Nm (0.2 m•kg, 1.4 ft•lb) 4 Nm (0.4 m•kg, 2.9 ft•lb) 1 Handlebar removal Extent of removal: Extent of removal Order...
  • Page 201 CHAS HANDLEBAR EC5B8000 THROTTLE DISASSEMBLY 4 Nm (0.4 m•kg, 2.9 ft•lb) 1 Throttle disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks THROTTLE DISASSEMBLY Grip cap (lower) Grip cap (upper) Grip assembly Grip (right) Refer to “REMOVAL POINTS”. Tube guide 5-41...
  • Page 202 CHAS HANDLEBAR EC5B3000 REMOVAL POINTS EC5B3100 Master cylinder 1. Remove: 9Master cylinder bracket 1 9Master cylinder 2 9Do not let the master cylinder hang on the brake hose. 9Keep the master cylinder cap side horizontal to prevent air from coming in. EC5B3200 Grip 1.
  • Page 203 CHAS HANDLEBAR 2. Install: 9Grip cap (upper) 1 9Grip cap (lower) 2 9Bolt (grip cap) 3 NOTE: Temporarily tighten the bolts (grip cap). EC5B5210 Handlebar 1. Install: 9Handlebar 1 9Handlebar holder 2 9Bolt (handlebar holder) 3 28 Nm (2.8 m•kg, 20 ft•lb) NOTE: 9 The upper handlebar holder should be installed with the punched mark a forward.
  • Page 204 CHAS HANDLEBAR 4. Install: 9Throttle cable 1 To tube guide 2. NOTE: Apply the lithium soap base grease on the throt- tle cable end and tube guide cable winding por- tion. 5. Install: 9Roller 1 9Collar 2 NOTE: 9Apply the lithium soap base grease on the roller sliding surface.
  • Page 205 CHAS HANDLEBAR 10. Install: 9Bolt (grip cap) 1 4 Nm (0.4 m•kg, 2.9 ft•lb) 9Install the grip cap so that the gaps a a and b b between the bolt (grip cap) and brake lever 2 2 are equal. If you make a mistake in the grip cap installation position, the brake lever may contact the grip cap, resulting in poor brake performance.
  • Page 206 CHAS HANDLEBAR a of the number 14. Clamp the clamp portion plate to the handlebar. 15. Insert the end of the fuel breather hose 1 into the hole of the number plate. 5-46...

  • Page 207: Steering

    CHAS STEERING EC560000 23 Nm (2.3 m•kg, 17 ft•lb) 145 Nm (14.5 m•kg, 105 ft•lb) TIGHTENING STEPS: 9 Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb) 9 Loosen it one turn. 9 Retighten it. 7 Nm (0.7 m•kg, 5.1 ft•lb) 20 Nm (2.0 m•kg, 14 ft•lb) 1 Under bracket removal 2 Bearing removal Extent of removal:...
  • Page 208 CHAS STEERING EC563000 REMOVAL POINTS EC563202 Ring nut 1. Remove: 9Ring nut 1 Use the ring nut wrench 2. Ring nut wrench: YU-33975/90890-01403 Support the steering shaft so that it may not fall down. EC563300 Bearing (lower) 1. Remove: 9Bearing (lower) 1 Use the floor chisel 2.
  • Page 209 CHAS STEERING EC564101 Bearing and ball race 1. Wash the bearings and ball races with a sol- vent. 2. Inspect: 9Bearing 1 9Ball race Pitting/Damage Replace bearings and ball races as a set. Install the bearing in the ball races. Spin the bearings by hand.
  • Page 210 CHAS STEERING 4. Install: 9Plain washer 1 9Ring nut 2 7 Nm (0.7 m•kg, 5.1 ft•lb) Tighten the ring nut using the ring nut wrench 3. Refer to “STEERING HEAD INSPECTION AND ADJUSTMENT” section in the CHAP- TER 3. 5. Check the steering shaft by turning it lock to lock.
  • Page 211 CHAS STEERING 9. After tightening the nut, check the steering for smooth movement. If not, adjust the steering by loosening the ring nut little by little. 10. Adjust: 9Front fork top end Front fork top end (standard) a a : 5 mm (0.20 in) 11.

  • Page 212: Swingarm

    CHAS SWINGARM EC570000 53 Nm (5.3 m•kg, 38 ft•lb) 80 Nm (8.0 m•kg, 58 ft•lb) 7 Nm (0.7 m•kg, 51 ft•lb) 19 Nm (1.9 m•kg, 13 ft•lb) 85 Nm (8.5 m•kg, 61 ft•lb) 1 Swingarm removal Extent of removal: Extent of removal Order Part name Q’ty...
  • Page 213 CHAS SWINGARM EC578000 SWINGARM DISASSEMBLY 80 Nm (8.0 m•kg, 58 ft•lb) 5 Nm (0.5 m•kg, 3.6 ft•lb) 80 Nm (8.0 m•kg, 58 ft•lb) 1 Swingarm disassembly 2 Connecting rod removal and disassembly Extent of removal: 3 Relay arm removal and disassembly Extent of removal Order Part name...
  • Page 214 CHAS SWINGARM EC573000 REMOVAL POINTS EC573200 Bearing 1. Remove: 9Bearing 1 NOTE: Install the bearing by pressing its outer race. EC574010 INSPECTION Wash the bearings, bushes, collars, and covers in a solvent. EC574111 Swingarm 1. Inspect: 9Bearing 1 9Bush 2 Free play exists/Unsmooth revolution/Rust Replace bearing and bush as a set.
  • Page 215 CHAS SWINGARM EC575000 ASSEMBLY AND INSTALLATION EC575202 Bearing and oil seal 1. Install: 9Bearing 1 9Oil seal 2 To swingarm. NOTE: 9Apply the molybdenum disulfide grease on the bearing when installing. 9Install the bearing by pressing it on the side hav- ing the manufacture's marks or numbers.
  • Page 216 CHAS SWINGARM EC5751B1 Swingarm 1. Install: 9Bush 1 9Thrust bearing 2 9Oil seal 3 9Collar 4 To swingarm 5. NOTE: Apply the molybdenum disulfide grease on the bushes, thrust bearings and oil seal lips. 2. Install: 9Collar 1 To relay arm 2. NOTE: Apply the molybdenum disulfide grease on the collars, bearings and oil seal lips.
  • Page 217 CHAS SWINGARM 5. Install: 9Relay arm 1 9Bolt (relay arm) 2 9Plain washer 3 9Nut (relay arm) 4 To swingarm. NOTE: 9Apply the molybdenum disulfide grease on the bolt. 9Do not tighten the nut yet. 6. Install: 9Swingarm 1 9Pivot shaft 2 85 Nm (8.5 m•kg, 61 ft•lb) NOTE: 9Apply the molybdenum disulfide grease on the...
  • Page 218 CHAS SWINGARM 10. Tighten: 9Nut (connecting rod) 1 80 Nm (8.0 m•kg, 58 ft•lb) 11. Tighten: 9Nut (relay arm) 1 80 Nm (8.0 m•kg, 58 ft•lb) 12. Install: 9Cap 1 NOTE: Install the cap with its mark a facing forward. 13.

  • Page 219: Rear Shock Absorber

    CHAS REAR SHOCK ABSORBER EC580000 56 Nm (5.6 m•kg, 40 ft•lb) 53 Nm (5.3 m•kg, 38 ft•lb) 29 Nm (2.9 m•kg, 21 ft•lb) 1 Rear shock absorber removal 2 Rear shock absorber disassembly Extent of removal: Extent of removal Order Part name Q’ty Remarks...
  • Page 220 1. Wear eye protection to prevent eye damage from escaping gas and/or metal chips. To dispose of a damaged or worn-out shock absorber, take the unit to your Yamaha dealer for this disposal procedure. 5-60...
  • Page 221 CHAS REAR SHOCK ABSORBER EC583000 REMOVAL POINTS EC583320 Bearing 1. Remove: 9Stopper ring (upper bearing) 1 NOTE: Press in the bearing while pressing its outer race and remove the stopper ring. 2. Remove: 9Upper bearing 1 NOTE: Remove the bearing by pressing its outer race. 3.
  • Page 222 CHAS REAR SHOCK ABSORBER EC585000 ASSEMBLY AND INSTALLATION EC585320 Bearing 1. Install: Upper Bearing 1 NOTE: Install the bearing parallel until the stopper ring groove appears by pressing its outer race. Do not apply the grease on the bearing outer race because it will wear the rear shock absorber surface on which the bear- ing is press fitted.
  • Page 223 CHAS REAR SHOCK ABSORBER 3. Adjust: 9Spring length (installed) a Spring length (installed) a a : Standard Extent of length adjustment 248 mm (9.76 in) 242~260 mm (9.53~10.24 in) *262 mm (10.31 in) *257~275 mm (10.12~10.83 in) *For EUROPE NOTE: The length of the spring (installed) changes 1.5 mm (0.06 in) per turn of the adjuster.
  • Page 224 CHAS REAR SHOCK ABSORBER 3. Install: 9Rear shock absorber 4. Install: 9Bolt (rear shock absorber-frame) 1 9Nut (rear shock absorber-frame) 2 56 Nm (5.6 m•kg, 40 ft•lb) NOTE: Apply the molybdenum disulfide grease on the bolt. 5. Install: 9Plain washer 1 9Bolt (rear shock absorber-relay arm) 2 53 Nm (5.3 m•kg, 38 ft•lb) NOTE:...

  • Page 225: Electrical Components And Wiring Diagram

    ELEC ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC600000 ELECTRICAL EC610000 ELECTRICAL COMPONENTS AND WIRING DIAGRAM EC611000 ELECTRICAL COMPONENTS 1 “ENGINE STOP” button COLOR CODE 2 Ignition coil B....Black 3 CDI unit O ....Orange 4 CDI magneto B/R ....Brack/Red 5 Spark plug B/W ....Black/White G/L ....Green/Blue G/W....Green/White...

  • Page 226: Ignition System

    ELEC IGNITION SYSTEM EC620000 IGNITION SYSTEM EC621002 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 *Clean or replace Spark gap test spark plug.
  • Page 227 ELEC IGNITION SYSTEM EC622001 å SPARK GAP TEST 1. Disconnect the spark plug cap from spark plug. 2. Connect the dynamic spark tester 1 (igni- tion checker 2 ) as shown. 9Spark plug cap 3 9Spark plug 4 A For USA and CDN B Except for USA and CDN ∫...
  • Page 228 ELEC IGNITION SYSTEM EC626002 IGNITION COIL INSPECTION 1. Inspect: 9Primary coil resistance Out of specification Replace. Tester (+) lead Orange lead 1 Tester (–) lead Black lead 2 Primary coil Tester selector resistance position 0.14~0.20Ω at Ω × 1 20°C (68°F) 2.
  • Page 229 ELEC IGNITION SYSTEM EC627011 CDI MAGNETO INSPECTION 1. Inspect: 9Pick-up coil resistance Out of specification Replace. Tester (+) lead White/ Red lead 1 Tester (–) lead White/ Blue lead 2 Pick–up coil Tester selector resistance position 248~372Ω at Ω × 100 20°C (68°F) 2.
  • Page 230 SETTING EC700000 TUNING EC710000 ENGINE EC711001 Carburetor setting 9The role of fuel is to cool the engine, and in the case of a 2-stroke engine, to lubricate the engine addition power generation. Accordingly, if a mixture of air and fuel is too lean, abnormal combustion will occur, and engine seizure may result.
  • Page 231 SETTING That is: 9Higher temperature expands the air with its resultant reduced density. 9Higher humidity reduces the amount of oxygen in the air by so much of the water vapor in the same air. 9Lower atmospheric pressure (at a high altitude) reduces the density of the air.
  • Page 232 SETTING EC714060 Effect of setting parts in relation to throttle valve opening Throttle valve opening Setting part Full-closed 1/4 3/4 Full-open Pilot air screw Pilot jet Diameter of straight portion Clip position Throttle valve Main jet 1 Throttle valve opening 2 Full-open 3 Full-closed EC715002...
  • Page 233 SETTING EC716001 Pilot air screw adjustment The richness of 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 mix- ture at low speeds, and turning out it will lean out the mixture.
  • Page 234 SETTING EC718010 Jet needle groove position adjustment Should the engine be hard to run smoothly at intermediate speeds, the jet needle 1 must be adjusted. If the mixture is too rich or too lean at intermediate speed operation, irregular engine operation and poor acceleration will result.
  • Page 235 SETTING EC719071 Jet needle adjustment (For USA, CDN, ZA, AUS and NZ) On the carburetors used in the YZ125, the main nozzle is a non disassembly type, so it can not replaced. Therefore, carburetor setting requires the change of the jet needle. 6BGK9-74 6BGK9-75 1.
  • Page 236 SETTING EC719071 Jet needle adjustment (For EUROPE) On the carburetors used in the YZ125, the main nozzle is a non disassembly type, so it can not replaced. Therefore, carburetor setting requires the change of the jet needle. 6BHY1-74 6BHY1-75 1. The jet needle setting parts, having the same 6BHY1-76 taper angle, are available in different straight portion diameters and in different taper start-...
  • Page 237 SETTING EC71B040 Relationship with throttle opening The flow of the fuel through the carburetor main system is controlled by the main jet and then, it is further regulated by the area between the main nozzle and the jet needle. On the relationship between the fuel flow and the throttle opening, the fuel flow relates to the straight portion of the jet needle at full closed~1/8 throttle, to the 1st...
  • Page 238 SETTING EC71Q000 Carburetor setting parts Part name Size Part number Main jet Lean #420 137-14143-84 #430 137-14143-86 #440 137-14143-88 *(STD) #450 137-14143-90 (STD) #460 137-14143-92 #470 137-14143-94 #480 137-14143-96 Rich #490 137-14143-98 Pilot jet 2 2 Lean 4KM-14142-20 #22.5 4KM-14142-22 (STD) 4KM-14142-25 #27.5...
  • Page 239 SETTING EC71C020 Road condition and examples of carburetor setting Conditions 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) Parts (Winter) (Spring, Autumn) (Summer) (Winter) (Spring, Autumn) (Summer) #470 #460 #450 #490...
  • Page 240 SETTING Symptom Setting Checking 0~1/4 throttle Use jet needle having a smaller Number of turns-back *Hard breathing diameter. Correct properly Speed down Overflow from carburetor 0~1/4 throttle Use jet needle having a larger Poor acceleration diameter. White smoke Unstable at low speeds Lower jet needle clip position.
  • Page 241 SETTING EC71M001 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 242 SETTING EC720000 CHASSIS EC71P002 Selection of the secondary reduction ratio (Sprocket) Secondary Number of driven sprocket teeth reduction = —————————————— Number of drive sprocket teeth ratio Standard secondary 48/13 (3.692) reduction ratio <Requirement for selection of secondary gear reduction ratio> 9It is generally said that the secondary gear ratio should be reduced for a longer straight portion of a speed course and should be increased for...
  • Page 243 SETTING EC72N000 Drive and driven sprockets setting parts Part name Size Part number Drive sprocket 1 1 9383A-12017 (STD) 9383A-13031 9383A-14054 Driven sprocket 2 2 5ET-25447-00 (STD) 5ET-25448-00 5ET-25449-00 5ET-25450-00 5ET-25451-00 5ET-25452-00 EC721002 Tire pressure Tire pressure should be adjust to suit the road surface condition of the circuit.
  • Page 244 SETTING EC722011 Front fork setting The front fork setting should be made depending on the rider’s feeling of an actual run and the cir- cuit conditions. The front fork setting includes the following three factors: 1. Setting of air spring characteristics 9Change the fork oil level.
  • Page 245 SETTING EC727021 Spring preload adjustment The spring preload is adjusted by installing the adjustment washer 1 between the fork spring 2 and damper rod 3. Do not install three or more adjustment washers for each front fork. Always adjust each front fork to the same setting.
  • Page 246 SETTING 2. Use of stiff spring Generally a stiff spring gives a stiff riding feeling. Rebound damping tends to become weaker, resulting in lack of a sense of con- tact with the road surface or in a vibrating handlebar. To set a stiff spring: 9Change the rebound damping.
  • Page 247 SETTING EC72P010 Front fork setting parts 9Adjustment washer 1 TYPE (thickness) PART NUMBER T=2.3 mm (0.09 in) 4SS-23364-L0 9Front fork spring 2 [Equal pitch spring ] I.D. SPRING SPRING TYPE MARK RATE PART NUMBER (slits) 0.380 4SS-23141-10 SOFT 0.390 4SS-23141-20 I-II 0.400 4SS-23141-30...
  • Page 248 SETTING EC72B000 Rear suspension setting The rear suspension setting should be made depending on the rider’s feeling of an actual run and the circuit conditions. The rear suspension setting includes the follow- ing two factors: 1. Setting of spring preload 9Change the set length of the spring.
  • Page 249 SETTING NOTE: 9 If the machine is new and after it is broken in, the same set length of the spring may change because of the initial fatigue, etc. of the spring. Therefore, be sure to make re-evaluation. 9 If the standard figure cannot be achieved by adjusting the spring adjuster and changing the spring set length, replace the spring with an optional one and make re-adjustment.
  • Page 250 SETTING When using a rear cushion other than cur- rently installed, use the one whose overall a a does not exceed the standard as length it may result in faulty performance. Never use one whose overall length is greater than standard. Length a a of standard shock: 485.5 mm (19.11 in) å...
  • Page 251 SETTING EC72Q011 Rear shock absorber setting parts 9Rear shock spring 1 [Equal pitch spring ] I.D. SPRING SPRING SPRING TYPE COLOR FREE RATE PART NUMBER /POINT LENGTH SOFT 5DH-22212-70 Brown/1 5DH-22212-10 Green/1 5DH-22212-20 Red/1 5DH-22212-30 Black/1 STIFF 5DH-22212-40 Blue/1 5DH-22212-50 Yellow/1 5DH-22212-60 Pink/1...

  • Page 252: Suspension Setting

    SETTING EC72H010 Suspension setting 9Front fork NOTE: 9If 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. 9Before any change, set the rear shock absorber sunken length to the standard figure 90~100 mm (3.5~3.9 in).
  • Page 253 SETTING 9Rear shock absorber NOTE: 9If 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. 9Adjust the rebound damping in 2-click increments or decrements. 9Adjust the low compression damping in 1-click increments or decrements.
  • Page 254 YAMAHA MOTOR CO., LTD. 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN JAPAN 2000.6 | 2.9 ´ 1 PRINTED ON RECYCLED PAPER i E j...

Table of Contents