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Yamaha YBR125ED 2005 Service Manual

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2005
YBR125ED
3D9-F8197-E0
SERVICE MANUAL

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Table of Contents

Troubleshooting

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  Summary of Contents for Yamaha YBR125ED 2005

  • Page 1 2005 YBR125ED 3D9-F8197-E0 SERVICE MANUAL...
  • Page 2 EAS00000 YBR125ED 2005 SERVICE MANUAL ©2005 by Yamaha Motor Co., Ltd. First edition, January 2005 All rights reserved. Any reproduction or unauthorized use without the written permission of Yamaha Motor Co., Ltd. is expressly prohibited.
  • Page 3 EAS00002 NOTICE This manual was produced by the Yamaha Motor Company, Ltd. primarily for use by Yamaha deal- ers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual. Therefore, anyone who uses this book to perform maintenance and repairs on Yamaha vehicles should have a basic understanding of mechanics and the techniques to repair these types of vehicles.
  • Page 4: How To Use This Manual

    EAS00007 HOW TO USE THIS MANUAL This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive explanations of all installation, removal, disassembly, assembly, repair and check procedures are laid out with the individual steps in sequential order. 1 The manual is divided into chapters.
  • Page 5: General Information

    EAS00009 SYMBOLS The following symbols are not relevant to SPEC every vehicle. Symbols 1 to 8 indicate the INFO subject of each chapter. 1 General information 2 Specifications 3 Periodic checks and adjustments CHAS 4 Chassis 5 Engine 6 Carburetor 7 Electrical system 8 Troubleshooting CARB...
  • Page 6: Table Of Contents

    EAS00011 TABLE OF CONTENTS GENERAL INFORMATION INFO SPECIFICATIONS SPEC PERIODIC CHECKS AND ADJUSTMENTS CHASSIS CHAS ENGINE CARBURETOR CARB – ELECTRICAL SYSTEM ELEC TROUBLESHOOTING TRBL SHTG...
  • Page 7 INFO CHAPTER 1 GENERAL INFORMATION VEHICLE IDENTIFICATION................1-1 VEHICLE IDENTIFICATION NUMBER .............1-1 MODEL LABEL..................1-1 IMPORTANT INFORMATION ................. 1-2 PREPARATION FOR REMOVAL AND DISASSEMBLY......1-2 REPLACEMENT PARTS................1-2 GASKETS, OIL SEALS AND O-RINGS ............ 1-2 LOCK WASHERS/PLATES AND COTTER PINS ........1-3 BEARINGS AND OIL SEALS ..............
  • Page 8: General Information

    VEHICLE IDENTIFICATION INFO EAS00014 GENERAL INFORMATION VEHICLE IDENTIFICATION EAS00017 VEHICLE IDENTIFICATION NUMBER The vehicle identification number 1 is stamped into the right side of the steering head pipe. EAS00018 MODEL LABEL The model label 1 is affixed to the frame. This information will be needed to order spare parts.
  • Page 9: Important Information

    5. Keep all parts away from any source of fire. EAS00021 REPLACEMENT PARTS Use only genuine Yamaha parts for all replacements. Use oil and grease recom- mended by Yamaha for all lubrication jobs. Other brands may be similar in function and appearance, but inferior in quality.
  • Page 10: Lock Washers/Plates And Cotter Pins

    IMPORTANT INFORMATION INFO EAS00023 LOCK WASHERS/PLATES AND COTTER PINS After removal, replace all lock washers/plates 1 and cotter pins. After the bolt or nut has been tightened to specification, bend the lock tabs along a flat of the bolt or nut. EAS00024 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manu-...
  • Page 11: Checking The Connections

    CHECKING THE CONNECTIONS INFO EAS00026 CHECKING THE CONNECTIONS Check the leads, couplers, and connectors for stains, rust, moisture, etc. 1. Disconnect: • lead • coupler • connector 2. Check: • lead • coupler • connector Moisture → Dry with an air blower. Rust/stains →...
  • Page 12: Special Tools

    SPECIAL TOOLS INFO EAS00027 SPECIAL TOOLS The following special tools are necessary for complete and accurate tune-up and assembly. Use only the appropriate special tools as this will help prevent damage caused by the use of inappropri- ate tools or improvised techniques. Special tools, part numbers or both may differ depending on the country.
  • Page 13 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Tappet adjusting tool 90890-01311 YM-08035-A This tool is used to adjust the valve clear- ance. Fuel level gauge 90890-01312 YM-01312-A This gauge is used to measure the fuel level in the float chamber. T-handle 90890-01326 YM-01326...
  • Page 14 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Compression gauge 90890-03081 YU-33223 These tools are used to measure the engine compression. Pocket tester 90890-03112 YU-03112-C This tool is used to check the electrical system. Timing light 90890-03141 YU-03141 This tool is used to check the ignition tim- ing.
  • Page 15 This tool is used for lapping the valves. Ignition checker 90890-06754 YM-34487 This tool is used to check the ignition sys- tem components. Yamaha bond No. 1215 90890-85505 This bond is used to seal two mating sur- faces (e.g., crankcase mating surfaces). 1 - 8...
  • Page 16 SPEC CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS ................ 2-1 ENGINE SPECIFICATIONS ................2-2 CHASSIS SPECIFICATIONS ................2-10 ELECTRICAL SPECIFICATIONS ..............2-14 CONVERSION TABLE .................. 2-16 GENERAL TIGHTENING TORQUE SPECIFICATIONS.......2-16 TIGHTENING TORQUES ................2-17 ENGINE TIGHTENING TORQUES............2-17 CHASSIS TIGHTENING TORQUES............2-19 LUBRICATION POINTS AND LUBRICANT TYPES ........2-21 ENGINE....................
  • Page 17: Specifications

    SPEC GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model YBR125 Model code 3D91 Dimensions Overall length 1,980 mm (78.0 in) Overall width 745 mm (29.3 in) Overall height 1,080 mm (42.5 in) Seat height 780 mm (30.7 in) Wheelbase 1,290 mm (50.8 in) Minimum ground clearance 175 mm (6.89 in) Minimum turning radius...
  • Page 18: Engine Specifications

    SPEC ENGINE SPECIFICATIONS ENGINE SPECIFICATIONS Item Standard Limit Engine Engine type Air-cooled 4-stroke, SOHC ---- Displacement 123.7 cm (7.55 cu.in) ---- Cylinder arrangement Forward-inclined single cylinder ---- Bore × stroke 54.0 × 54.0 mm (2.13 × 2.13 in) ---- Compression ratio 10.0 : 1 ---- Standard compression pressure...
  • Page 19 SPEC ENGINE SPECIFICATIONS Item Standard Limit Camshaft Drive system Chain drive (left) ---- Intake camshaft lobe dimensions Measurement A 25.881 ~ 25.981 mm (1.0189 ~ 1.0229 in) 25.851 mm (1.0178 in) Measurement B 21.194 ~ 21.294 mm (0.8344 ~ 0.8383 in) 21.164 mm (0.8332 in) Exhaust camshaft lobe dimensions Measurement A...
  • Page 20 SPEC ENGINE SPECIFICATIONS Item Standard Limit Valves, valve seats, valve guides Valve clearance (cold) Intake 0.08 ~ 0.12 mm (0.0031 ~ 0.0047 in) ---- Exhaust 0.10 ~ 0.14 mm (0.0039 ~ 0.0055 in) ---- Valve dimensions Head Diameter Face Width Seat Width Margin Thickness Valve head diameter A...
  • Page 21 SPEC ENGINE SPECIFICATIONS Item Standard Limit Valve stem runout ---- 0.010 mm (0.0004 in) Valve seat width (cylinder head side) Intake 0.90 ~ 1.10 mm (0.0354 ~ 0.0433 in) 1.6 mm (0.06 in) Exhaust 0.90 ~ 1.10 mm (0.0354 ~ 0.0433 in) 1.6 mm (0.06 in) Valve springs...
  • Page 22 SPEC ENGINE SPECIFICATIONS Item Standard Limit Cylinder Bore 54.024 ~ 54.056 mm (2.1269 ~ 2.1282 in) 54.156 mm (2.1321 in) Measuring point 40 mm (1.57 in) ---- Piston Piston-to-cylinder clearance 0.019 ~ 0.035 mm (0.0007 ~ 0.0014 in) 0.15 mm (0.0059 in) Diameter D 53.997 ~ 54.029 mm (2.1259 ~ 2.1271 in)
  • Page 23 SPEC ENGINE SPECIFICATIONS Item Standard Limit 2nd ring Ring type Taper ---- Dimensions (B × T) 1.00 × 2.10 mm (0.039 × 0.082 in) ---- End gap (installed) 0.30 ~ 0.45 mm (0.012 ~ 0.018 in) 0.80 mm (0.031 in) Ring side clearance 0.020 ~ 0.060 mm (0.0008 ~ 0.0024 in) 0.120 mm...
  • Page 24 SPEC ENGINE SPECIFICATIONS Item Standard Limit Clutch spring Free length 29.30 mm (1.15 in) 27.84 mm (1.10 in) Spring quantity 4 pcs ---- Long clutch push rod bending ---- 0.500 mm (0.0197 in) Transmission Transmission type Constant mesh 5-speed ---- Primary reduction system Helical gear ----...
  • Page 25 SPEC ENGINE SPECIFICATIONS Item Standard Limit Carburetor Type/quantity VM22SH/1 ---- Manufacturer MIKUNI ---- ID mark 3D91 00 ---- Main jet #97.5 ---- Main air jet ø0.9 ---- Jet needle 5EJ7-2 ---- Needle jet N-7M ---- Pilot air jet 1 Pilot air jet 2 ø1.3 Pilot outlet ø1.0...
  • Page 26: Chassis Specifications

    SPEC CHASSIS SPECIFICATIONS CHASSIS SPECIFICATIONS Item Standard Limit Frame Frame type Diamond ---- Caster angle 26.33° ---- Trail 90.0 mm (3.54 in) ---- Front wheel Wheel type Cast wheel ---- J18 × 1.60 Size ---- Material Aluminum ---- Wheel travel 110.0 mm (4.33 in) ---- Wheel runout...
  • Page 27 SPEC CHASSIS SPECIFICATIONS Item Standard Limit Rear tire Tire type With tube ---- Size 90/90-18 57P ---- Manufacturer/model CHENG SHIN/SAKURA S-180 ---- PIRELLI/CITY DEMON ---- Tire pressure (cold tire) 0 ~ 90 kg (0 ~ 198 lb) 200 kPa (2.00 kgf/cm , 29 psi) ---- 90 kg ~ Maximum load...
  • Page 28 SPEC CHASSIS SPECIFICATIONS Item Standard Limit Steering Steering bearing type Ball and race bearing ---- Lock-to-lock angle (left) 47° ---- Lock-to-lock angle (right) 47° ---- No./size of steel balls Upper 16 pcs 0.250 in ---- Lower 16 pcs 0.250 in ---- Front suspension Suspension type...
  • Page 29 SPEC CHASSIS SPECIFICATIONS Item Standard Limit Swingarm Free play limit (at the end of the swin- ---- 1.0 mm garm)-radial (0.04 in) Free play limit (at the end of the swin- ---- 1.0 mm garm)-axial (0.04 in) Drive chain Type/manufacturer DID428V2/DAIDO ---- Link quantity...
  • Page 30: Electrical Specifications

    SPEC ELECTRICAL SPECIFICATIONS ELECTRICAL SPECIFICATIONS Item Standard Limit System voltage 12 V ---- Ignition system Ignition system type DC. C.D.I. ---- Ignition timing (B.T.D.C.) 7.0° at 1,400 r/min ---- Advanced type Digital ---- DC.C.D.I. 248 ~ 372 Ω at 20 °C (68 °F)/white–red Pickup coil resistance/color ---- C.D.I.
  • Page 31 SPEC ELECTRICAL SPECIFICATIONS Item Standard Limit Indicator lights (voltage/wattage × quantity) 14 V 3 W × 1 Neutral indicator light ---- 14 V 3 W × 2 Turn signal indicator light ---- 14 V 3 W × 1 High beam indicator light ---- Electric starting system System type...
  • Page 32: Conversion Table

    CONVERSION TABLE/ SPEC GENERAL TIGHTENING TORQUE SPECIFICATIONS EAS00028 EAS00030 CONVERSION TABLE GENERAL TIGHTENING TORQUE All specification data in this manual are listed SPECIFICATIONS in SI and METRIC UNITS. This chart specifies tightening torques for stan- Use this table to convert METRIC unit data to dard fasteners with a standard ISO thread IMPERIAL unit data.
  • Page 33: Tightening Torques

    SPEC TIGHTENING TORQUES TIGHTENING TORQUES ENGINE TIGHTENING TORQUES Tightening torque Thread Part to be tightened Part name Q’ty Remarks size Nm m · kg ft · lb Cylinder head Bolt Bolt Oil gallery bolt Bolt Spark plug — 9.4 Sealant Camshaft sprocket cover Bolt Tappet cover (intake and exhaust...
  • Page 34 SPEC TIGHTENING TORQUES Tightening torque Thread Part to be tightened Part name Q’ty Remarks size Nm m · kg ft · lb Clutch pressure plate Screw Clutch boss Short clutch push rod locknut Bearing retainer Bolt Shift pedal Bolt Shift drum segment Screw Stopper lever Bolt...
  • Page 35: Chassis Tightening Torques

    SPEC TIGHTENING TORQUES CHASSIS TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Remarks Nm m · kg ft · lb Engine mounting: Front mounting bolt Lower engine bracket and frame Rear mounting bolt Upper mounting bolt Left upper engine bracket and frame Right upper engine bracket and frame Brake caliper bracket bolt Brake disc and front wheel...
  • Page 36 SPEC TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Remarks Nm m · kg ft · lb Passenger footrest bracket (left and right), center- stand and frame Brake torque rod and swingarm Pivot shaft and pivot shaft nut Rear shock absorber assembly and swingarm Rear shock absorber assembly and frame Fuel tank and frame...
  • Page 37: Lubrication Points And Lubricant Types

    Long clutch push rod ends and ball Transmission gears (wheel and pinion) Main and drive axle Shift forks and shift fork guide bars Shift drum Yamaha bond Crankcase mating surface No.1215 Yamaha bond A.C. magneto lead grommet (A.C. magneto cover) No.1215...
  • Page 38: Chassis

    EAS00032 CHASSIS Lubrication point Lubricant Front wheel oil seal lip Speedometer gear unit inner surface YAMAHA GREASE Rear wheel oil seal lip and O-ring F 150G Rear wheel drive hub oil seal lip YAMAHA GREASE F 150G Rear brake camshaft...
  • Page 39: Lubrication Diagrams

    SPEC LUBRICATION DIAGRAMS EAS00034 LUBRICATION DIAGRAMS 1 Rocker arm 2 Rocker arm shaft 3 Camshaft 4 Crankshaft 5 Oil pump 6 Oil strainer 2 - 23...
  • Page 40 SPEC LUBRICATION DIAGRAMS 1 Camshaft 2 Rotary filter 3 Crankshaft 4 Main axle 5 Drive axle 2 - 24...
  • Page 41: Cable Routing

    SPEC CABLE ROUTING EAS00035 CABLE ROUTING 1 Front brake light switch lead 0 Front turn signal light lead (right) 2 Front brake hose A Main switch lead 3 Meter assembly lead B Throttle cable 4 Left handlebar switch lead C Clutch switch lead 5 Speedometer cable D Right handlebar switch lead 6 Clutch cable...
  • Page 42 SPEC CABLE ROUTING É Make sure that the headlight assembly lead is Ì Pass the throttle cable, front brake hose, front routed through the protective covering. brake light switch lead, and right handlebar Ê Connect the main switch lead, right handlebar switch lead through the guide.
  • Page 43 SPEC CABLE ROUTING 1 Clutch cable B Starter relay 2 C.D.I. unit C Starter motor lead 3 Fuel hose D Battery breather hose 4 Rectifier/regulator E Negative battery lead 5 Fuel sender F Carburetor overflow hose 6 Fuel sender lead G Ignition coil 7 Air vent hose H Horn...
  • Page 44 SPEC CABLE ROUTING È Fasten the wire harness at the white tape with Í Route the starter motor lead to the inside of the the holder. battery. É Fasten the fuel sender lead with the holder. Î Fasten the A.C. magneto lead and rear brake Ê...
  • Page 45 SPEC CABLE ROUTING Ò Pass the speedometer cable through the guide. Ó Route the starter motor lead in the groove in the lower engine bracket. Ô Pass the carburetor overflow hose through the guide. Õ Route the carburetor overflow hose in front of the battery breather hose, negative battery lead, and starter motor lead.
  • Page 46 SPEC CABLE ROUTING 1 Air vent hose A Clutch cable 2 Air induction system hose (air filter to air cut-off B Horn C Air induction system pipe valve assembly) 3 Carburetor heater lead D Air induction system hose (air cut-off valve 4 Air cut-off valve assembly assembly to cylinder head) 5 C.D.I.
  • Page 47 SPEC CABLE ROUTING È Face the ends of the hose clamp forward. Î Pass the throttle cable through the guide. É Face the ends of the hose clamp downward. Ï Fasten the front brake hose with the holder. Ê Install the air induction system hose (air filter to Ð...
  • Page 48 SPEC CABLE ROUTING 1 C.D.I. unit È Fasten the plastic locking tie next to the rectifier/ 2 Air cut-off valve assembly regulator bracket. 3 Rectifier/regulator É Fasten the carburetor heater lead with the plas- 4 Carburetor heater lead tic locking tie. Face the buckle of the plastic lock- 5 Thermo switch ing tie inward.
  • Page 49 SPEC CABLE ROUTING Ë Make sure that there is no slack in the rear turn Ï Fasten the wire harness, thermo switch lead, and signal light lead between the hole in the rear tail/brake light lead with the holder, making sure fender and the plastic locking tie.
  • Page 50 SPEC CABLE ROUTING Ó Be sure to route the wire harness to the inside of Ø Fasten the wire harness with the plastic locking the frame in the area shown in the illustration. tie. Cut off the excess end of the plastic locking Ô...
  • Page 51 SPEC CABLE ROUTING Þ Black ß Cut off the excess end of the plastic locking tie to 2 mm or less, and then face the end of the tie inward and upward in the range shown in the illustration. À Be sure to fasten the rear turn signal light lead (left) on its protective sleeve with the plastic locking tie.
  • Page 52 CHAPTER 3 PERIODIC CHECKS AND ADJUSTMENTS INTRODUCTION....................3-1 PERIODIC MAINTENANCE AND LUBRICATION CHART ......3-1 SIDE COVERS, SEAT AND FUEL TANK............3-3 BATTERY AND BATTERY BOX..............3-5 ENGINE ......................3-7 ADJUSTING THE VALVE CLEARANCE ..........3-7 CHECKING AND ADJUSTING THE EXHAUST GAS....... 3-9 ADJUSTING THE ENGINE IDLING SPEED ...........3-11 ADJUSTING THE THROTTLE CABLE FREE PLAY ......3-12 CHECKING THE SPARK PLUG .............
  • Page 53 ELECTRICAL SYSTEM................. 3-42 CHECKING AND CHARGING THE BATTERY........3-42 CHECKING THE FUSE................3-46 REPLACING THE HEADLIGHT BULB............3-47 ADJUSTING THE HEADLIGHT BEAM ...........3-48...
  • Page 54: Periodic Checks And Adjustments

    • From 30000 km, repeat the maintenance intervals starting from 6000 km. • Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools, data and technical skills. ODOMETER READING (× 1000 km)
  • Page 55 PERIODIC MAINTENANCE AND LUBRICATION CHART ODOMETER READING (× 1000 km) ANNUAL ITEM CHECK OR MAINTENANCE JOB CHECK √ √ √ √ • Check operation and for excessive play. Swingarm 14 * (See page 4-67.) • Lubricate with lithium-soap-based grease. Every 24000 km Drive chain •...
  • Page 56: Side Covers, Seat And Fuel Tank

    SIDE COVERS, SEAT AND FUEL TANK EAS00042 SIDE COVERS, SEAT AND FUEL TANK 16 Nm (1.6 m kg, 11 ft 30 Nm (3.0 m kg, 22 ft • • • • Order Job/Part Q’ty Remarks Removing the side covers, seat and Remove the parts in the order listed.
  • Page 57 SIDE COVERS, SEAT AND FUEL TANK 16 Nm (1.6 m kg, 11 ft 30 Nm (3.0 m kg, 22 ft • • • • Order Job/Part Q’ty Remarks Fuel hose (fuel cock side) NOTE: Before disconnecting the fuel hose, turn the fuel cock to “OFF”.
  • Page 58: Battery And Battery Box

    BATTERY AND BATTERY BOX BATTERY AND BATTERY BOX 14 14 7 Nm (0.7 m kg, 5.1 ft • • Order Job/Part Q’ty Remarks Removing the battery and battery Remove the parts in the order listed. Left side cover Refer to “SIDE COVERS, SEAT AND FUEL TANK”.
  • Page 59 BATTERY AND BATTERY BOX 14 14 7 Nm (0.7 m kg, 5.1 ft • • Order Job/Part Q’ty Remarks Headlight relay coupler Disconnect. Headlight relay Air vent hose Battery box For installation, reverse the removal pro- cedure. 3 - 6...
  • Page 60: Engine

    ADJUSTING THE VALVE CLEARANCE EAS00049 ENGINE ADJUSTING THE VALVE CLEARANCE The following procedure applies to all of the valves. NOTE: • Valve clearance adjustment should be made on a cold engine, at room temperature. • When the valve clearance is to be measured or adjusted, the piston must be at top dead center (TDC) on the compression stroke.
  • Page 61 ADJUSTING THE VALVE CLEARANCE M MMM M MMM M MMM M MMM M MMM a. Turn the crankshaft counterclockwise. b. When the piston is at TDC on the compres- sion stroke, align the “I” mark a on the A.C. magneto rotor with the stationary b on the A.C.
  • Page 62: Checking And Adjusting The Exhaust Gas

    ADJUSTING THE VALVE CLEARANCE/ CHECKING AND ADJUSTING THE EXHAUST GAS • Hold the adjusting screw to prevent it from moving and tighten the locknut to specifica- tion. Locknut 8 Nm (0.8 m · kg, 5.8 ft · lb) d. Measure the valve clearance again. e.
  • Page 63 CHECKING AND ADJUSTING THE EXHAUST GAS 3. Disconnect: • air induction system hose (air cut-off valve to cylinder head) 1 4. Stop air induction system operation. NOTE: Crimp the hose 1 running from the reed valve to the air cut-off valve to prevent the air cut-off valve from operating.
  • Page 64: Adjusting The Engine Idling Speed

    CHECKING AND ADJUSTING THE EXHAUST GAS/ ADJUSTING THE ENGINE IDLING SPEED 8. Measure: • CO density Out of specification → Adjust. Within specification → Check the air induc- tion system. Refer to “AIR INDUCTION SYSTEM” in chapter 6. CO density (when the air induc- tion system is not operating) 3.0 ~ 5.0% 9.
  • Page 65: Adjusting The Throttle Cable Free Play

    ADJUSTING THE ENGINE IDLING SPEED/ ADJUSTING THE THROTTLE CABLE FREE PLAY 3. Adjust: • engine idling speed M MMM M MMM M MMM M MMM M MMM a. Turn the pilot screw 1 in or out until it is lightly seated with the carburetor angle driver 2.
  • Page 66 ADJUSTING THE THROTTLE CABLE FREE PLAY 2. Adjust: • throttle cable free play M MMM M MMM M MMM M MMM M MMM Carburetor side a. Slide back the rubber cover 1. b. Loosen the locknut 2. c. Turn the adjusting nut 3 in direction a or b until the specified throttle cable free play is obtained.
  • Page 67: Checking The Spark Plug

    CHECKING THE SPARK PLUG EAS00060 CHECKING THE SPARK PLUG 1. Disconnect: • spark plug cap 2. Remove: • spark plug CAUTION: Before removing the spark plug, blow away any dirt accumulated in the spark plug well with compressed air to prevent it from fall- ing into the cylinder.
  • Page 68: Checking The Ignition Timing

    CHECKING THE IGNITION TIMING EAS00064 CHECKING THE IGNITION TIMING NOTE: Prior to checking the ignition timing, check the wiring connections of the entire ignition sys- tem. Make sure all connections are tight and free of corrosion. 1. Remove: • timing mark accessing screw 2.
  • Page 69: Measuring The Compression Pressure

    MEASURING THE COMPRESSION PRESSURE EAS00067 MEASURING THE COMPRESSION PRESSURE NOTE: Insufficient compression pressure will result in a loss of performance. 1. Measure: • valve clearance Out of specification → Adjust. Refer “ADJUSTING VALVE CLEARANCE”. 2. Start the engine, warm it up for several min- utes, and then turn it off.
  • Page 70: Checking The Engine Oil Level

    MEASURING THE COMPRESSION PRESSURE/ CHECKING THE ENGINE OIL LEVEL M MMM M MMM M MMM M MMM M MMM a. Set the main switch to “ON”. b. With the throttle wide open, crank the engine until the reading on the compression gauge stabilizes.
  • Page 71 CHECKING THE ENGINE OIL LEVEL 3. Check: • engine oil level The engine oil level should be between the minimum level mark a and maximum level mark b. Below the minimum level mark → Add the recommended engine oil to the proper level. NOTE: •...
  • Page 72: Changing The Engine Oil

    CHANGING THE ENGINE OIL EAS00076 CHANGING THE ENGINE OIL 1. Start the engine, warm it up for several min- utes, and then turn it off. 2. Place a container under the engine oil drain bolt. 3. Remove: • engine oil filler cap 1 •...
  • Page 73: Adjusting The Clutch Cable Free Play

    CHANGING THE ENGINE OIL/ ADJUSTING THE CLUTCH CABLE FREE PLAY 12.Check: • engine oil pressure M MMM M MMM M MMM M MMM M MMM a. Slightly loosen the oil gallery bolt 1. b. Start the engine and keep it idling until engine oil starts to seep from the oil gallery bolt.
  • Page 74: Cleaning The Air Filter Elements

    ADJUSTING THE CLUTCH CABLE FREE PLAY/ CLEANING THE AIR FILTER ELEMENTS d. Tighten the locknut. e. Slide the rubber cover to its original posi- tion. NOTE: If the specified clutch cable free play cannot be obtained on the handlebar side of the cable, use the adjusting nut on the engine side.
  • Page 75 CLEANING THE AIR FILTER ELEMENTS 2. Remove: • air filter case cover 1 • air filter element 1 • air filter element 2 3. Check: • air filter element 1 1 • air filter element 2 2 Damage → Replace. 4.
  • Page 76: Checking The Carburetor Joint And Intake Manifold

    CLEANING THE AIR FILTER ELEMENTS/ CHECKING THE CARBURETOR JOINT AND INTAKE MANIFOLD 6. Install: • air filter element 2 • air filter element 1 • air filter case cover CAUTION: Never operate the engine without the air fil- ter element installed. Unfiltered air will cause rapid wear of engine parts and may damage the engine.
  • Page 77: Checking The Fuel Hose And Fuel Cock Filter

    CHECKING THE FUEL HOSE AND FUEL COCK FILTER/ CHECKING THE CRANKCASE BREATHER HOSE EAS00097 CHECKING THE FUEL HOSE AND FUEL COCK FILTER 1. Remove: • left air duct Refer to “SIDE COVERS, SEAT AND FUEL TANK”. 2. Check: • fuel hose 1 Cracks/damage →...
  • Page 78: Checking The Exhaust System

    CHECKING THE EXHAUST SYSTEM EAS00099 CHECKING THE EXHAUST SYSTEM 1. Check: • muffler assembly 1 Cracks/damage → Replace. • exhaust pipe gasket 2 Exhaust gas leaks → Replace. 2. Check: • tightening torques Exhaust pipe bolts 3 10 Nm (1.0 m · kg, 7.2 ft · lb) Muffler bolt 4 22 Nm (2.2 m ·...
  • Page 79: Chassis

    ADJUSTING THE REAR BRAKE/ CHECKING THE BRAKE FLUID LEVEL CHASSIS EAS00113 ADJUSTING THE REAR BRAKE 1. Check: • brake pedal free play a Out of specification → Adjust. Brake pedal free play (at the end of the brake pedal) 20 ~ 30 mm (0.79 ~ 1.18 in) 2.
  • Page 80: Checking The Front Brake Pads

    CHECKING THE BRAKE FLUID LEVEL/ CHECKING THE FRONT BRAKE PADS 2. Check: • brake fluid level Below the minimum level mark a → Add the recommended brake fluid to the proper level. Recommended brake fluid DOT 3 or 4 WARNING •...
  • Page 81: Checking The Rear Brake Shoes

    CHECKING THE FRONT BRAKE PADS/ CHECKING THE REAR BRAKE SHOES/ ADJUSTING THE REAR BRAKE LIGHT SWITCH 2. Remove: • check plug 1 3. Check: • front brake pad Wear indicators 2 almost touch the brake disc → Replace the brake pads as a set. Refer “REPLACING FRONT...
  • Page 82: Adjusting The Rear Brake Light Switch

    ADJUSTING THE REAR BRAKE LIGHT SWITCH/ CHECKING THE FRONT BRAKE HOSE 3. Adjust: • rear brake light operation timing M MMM M MMM M MMM M MMM M MMM a. Hold the main body 1 of the rear brake light switch so that it does not rotate and turn the adjusting nut 2 in direction a or b until the rear brake light comes on at the proper...
  • Page 83: Bleeding The Hydraulic Brake System

    BLEEDING THE HYDRAULIC BRAKE SYSTEM EAS00133 BLEEDING THE HYDRAULIC BRAKE SYSTEM WARNING Bleed the hydraulic brake system when- ever: • the system is disassembled. • a brake hose is loosened, disconnected or replaced. • the brake fluid level is very low. •...
  • Page 84: Adjusting The Drive Chain Slack

    BLEEDING THE HYDRAULIC BRAKE SYSTEM/ ADJUSTING THE DRIVE CHAIN SLACK g. Loosen the bleed screw. NOTE: Loosening the bleed screw will release the pressure and cause the brake lever to contact the throttle grip. h. Tighten the bleed screw and then release the brake lever.
  • Page 85 ADJUSTING THE DRIVE CHAIN SLACK 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the rear wheel is elevated. 2.
  • Page 86: Lubricating The Drive Chain

    ADJUSTING THE DRIVE CHAIN SLACK/ LUBRICATING THE DRIVE CHAIN h. Tighten the wheel axle nut to specification. Wheel axle nut 91 Nm (9.1 m · kg, 66 ft · lb) i. Tighten the brake torque rod nut to specifi- cation. Brake torque rod nut 19 Nm (1.9 m ·...
  • Page 87: Checking And Adjusting The Steering Head

    CHECKING AND ADJUSTING THE STEERING HEAD EAS00146 CHECKING AND ADJUSTING THE STEERING HEAD 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the front wheel is elevated.
  • Page 88: Checking The Front Fork

    CHECKING AND ADJUSTING THE STEERING HEAD/ CHECKING THE FRONT FORK Lower ring nut (final tightening torque) 22 Nm (2.2 m · kg, 16 ft · lb) d. Check the steering head for looseness or binding by turning the front fork all the way in both directions.
  • Page 89: Adjusting The Rear Shock Absorber Assemblies

    ADJUSTING THE REAR SHOCK ABSORBER ASSEMBLIES EAS00160 ADJUSTING THE REAR SHOCK ABSORBER ASSEMBLIES The following procedure applies to both of the rear shock absorber assemblies. WARNING • Securely support the vehicle so that there is no danger of it falling over. •...
  • Page 90: Checking The Tires

    CHECKING THE TIRES EAS00166 CHECKING THE TIRES The following procedure applies to both of the tires. 1. Check: • tire pressure Out of specification → Regulate. WARNING • The tire pressure should only be checked and regulated when the tire temperature equals the ambient air temperature.
  • Page 91 Tube or tubeless Tubeless wheel tire • After extensive tests, the tires listed below have been approved by Yamaha Motor Co., Ltd. for this model. The front and rear tires should always be by the same manufacturer and of the same design.
  • Page 92 CHECKING THE TIRES Front tire Manufacturer Model Size SAKURA CHENG SHIN 2.75-18 42P S-901 CITY PIRELLI 2.75-18 42P DEMON Rear tire Manufacturer Model Size SAKURA 90/90- CHENG SHIN S-180 18 57P CITY 90/90- PIRELLI DEMON 18 57P WARNING • New tires have a relatively low grip on the road surface until they have been slightly worn.
  • Page 93: Checking The Wheels

    CHECKING THE WHEELS/ CHECKING AND LUBRICATING THE CABLES EAS00168 CHECKING THE WHEELS The following procedure applies to both of the wheels. 1. Check: • wheel Damage/out-of-round → Replace. WARNING Never attempt to make any repairs to the wheel. NOTE: After a tire or wheel has been changed or replaced, always balance the wheel.
  • Page 94: Lubricating The Levers And Pedals

    LUBRICATING THE LEVERS AND PEDALS/ LUBRICATING THE CENTERSTAND EAS00171 LUBRICATING THE LEVERS AND PEDALS Lubricate the pivoting point and metal-to-metal moving parts of the levers and pedals. Recommended lubricant Lithium-soap-based grease EAS00173 LUBRICATING THE CENTERSTAND Lubricate the pivoting point and metal-to-metal moving parts of the centerstand.
  • Page 95: Chk Adj

    CHECKING AND CHARGING THE BATTERY EAS00176 ELECTRICAL SYSTEM CHECKING AND CHARGING THE BATTERY WARNING Batteries generate explosive hydrogen gas and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive measures: • Wear protective eye gear when handling or working near batteries.
  • Page 96 CHECKING AND CHARGING THE BATTERY 3. Remove: • battery band • battery 4. Check: • electrolyte level The electrolyte level should be between the minimum level mark a and the maximum level mark b. Below the minimum level mark → Add dis- tilled water to the proper level.
  • Page 97 CHECKING AND CHARGING THE BATTERY • Do not use a high-rate battery charger. They force a high-amperage current into the battery quickly and can cause battery overheating and battery plate damage. • If it is impossible to regulate the charging current on the battery charger, be careful not to overcharge the battery.
  • Page 98 CHECKING AND CHARGING THE BATTERY 7. Check: • battery breather hose and battery vent Obstruction → Clean. Damage → Replace. 8. Connect: • battery breather hose 9. Install: • battery • battery band CAUTION: • When checking the battery, make sure the battery breather hose is properly installed and routed correctly.
  • Page 99: Checking The Fuse

    CHECKING THE FUSE EAS00181 CHECKING THE FUSE CAUTION: To avoid a short circuit, always set the main switch to “OFF” when checking or replacing a fuse. 1. Remove: • left side cover Refer to “SIDE COVERS, SEAT AND FUEL TANK”. 2.
  • Page 100: Replacing The Headlight Bulb

    CHECKING THE FUSE/ REPLACING THE HEADLIGHT BULB d. If the fuse immediately blows again, check the electrical circuit. Amperage Q’ty rating Fuse 15 A Spare 15 A WARNING Never use a fuse with an amperage rating other than that specified. Improvising or using a fuse with the wrong amperage rat- ing may cause extensive damage to the electrical system, cause the lighting and...
  • Page 101: Adjusting The Headlight Beam

    REPLACING THE HEADLIGHT BULB/ ADJUSTING THE HEADLIGHT BEAM 5. Remove: • headlight bulb 1 WARNING Since the headlight bulb gets extremely hot, keep flammable products and your hands away from the bulb until it has cooled down. 6. Install: • headlight bulb Secure the new headlight bulb with the headlight bulb holder.
  • Page 102: Chas

    CHAS CHAPTER 4 CHASSIS FRONT WHEEL AND BRAKE DISC............... 4-1 FRONT WHEEL ..................4-2 REMOVING THE FRONT WHEEL............4-3 CHECKING THE FRONT WHEEL ............4-3 CHECKING THE BRAKE DISC..............4-5 CHECKING THE SPEEDOMETER GEAR UNIT ........4-6 INSTALLING THE FRONT WHEEL ............4-6 REAR WHEEL, BRAKE SHOE PLATE, AND REAR WHEEL SPROCKET ....................
  • Page 103 CHAS STEERING HEAD..................4-52 HEADLIGHT AND METER ASSEMBLY ..........4-52 LOWER BRACKET ................. 4-54 REMOVING THE LOWER BRACKET.............4-56 CHECKING THE STEERING HEAD ............4-56 INSTALLING THE STEERING HEAD .............4-57 DRIVE CHAIN AND DRIVE SPROCKET ............4-59 REMOVING THE DRIVE CHAIN............. 4-61 CHECKING THE DRIVE CHAIN ............. 4-61 INSTALLING THE DRIVE CHAIN ............
  • Page 104: Front Wheel And Brake Disc

    CHAS FRONT WHEEL AND BRAKE DISC EAS00512 CHASSIS FRONT WHEEL AND BRAKE DISC Order Job/Part Q’ty Remarks Removing the front wheel and brake Remove the parts in the order listed. disc NOTE: Place the vehicle on a suitable stand so that the front wheel is elevated.
  • Page 105: Front Wheel

    CHAS FRONT WHEEL AND BRAKE DISC EAS00518 FRONT WHEEL Order Job/Part Q’ty Remarks Disassembling the front wheel Remove the parts in the order listed. Oil seal Bearing Spacer For assembly, reverse the disassembly procedure. 4 - 2...
  • Page 106: Removing The Front Wheel

    CHAS FRONT WHEEL AND BRAKE DISC EAS00519 REMOVING THE FRONT WHEEL 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the front wheel is elevated.
  • Page 107 CHAS FRONT WHEEL AND BRAKE DISC 3. Measure: • radial wheel runout 1 • lateral wheel runout 2 Over the specified limits → Replace. Radial wheel runout limit 1.0 mm (0.04 in) Lateral wheel runout limit 0.5 mm (0.02 in) 4.
  • Page 108: Checking The Brake Disc

    CHAS FRONT WHEEL AND BRAKE DISC EAS00527 CHECKING THE BRAKE DISC 1. Check: • brake disc Damage/galling → Replace. 2. Measure: • brake disc deflection Out of specification → Correct the brake disc deflection or replace the brake disc. Brake disc deflection limit (maxi- mum) 0.15 mm (0.0059 in) M MMM...
  • Page 109: Checking The Speedometer Gear Unit

    CHAS FRONT WHEEL AND BRAKE DISC 4. Adjust: • brake disc deflection M MMM M MMM M MMM M MMM M MMM a. Remove the brake disc. b. Rotate the brake disc by one bolt hole. c. Install the brake disc. NOTE: •...
  • Page 110 CHAS FRONT WHEEL AND BRAKE DISC 2. Install: • speedometer gear unit NOTE: • Make sure that the speedometer gear unit and the wheel hub are installed with the pro- jection a of the speedometer gear unit inserted in a slot b of the wheel hub. •...
  • Page 111: Rear Wheel, Brake Shoe Plate, And Rear Wheel Sprocket

    REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET EAS00553 REAR WHEEL, BRAKE SHOE PLATE, AND REAR WHEEL SPROCKET REAR WHEEL 19 Nm (1.9 m kg, 13 ft • • 91 Nm (9.1 m kg, 66 ft • • 12 8 Order Job/Part...
  • Page 112 REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET 19 Nm (1.9 m kg, 13 ft • • 91 Nm (9.1 m kg, 66 ft • • 12 8 Order Job/Part Q’ty Remarks Spacer Chain puller Refer to “INSTALLING THE REAR WHEEL AND REAR WHEEL SPROCKET”.
  • Page 113: Brake Shoe Plate And Rear Wheel Sprocket

    REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET EAS00558 BRAKE SHOE PLATE AND REAR WHEEL SPROCKET Apply YAMAHA GREASE F 150G Order Job/Part Q’ty Remarks Removing the brake shoe plate and Remove the parts in the order listed.
  • Page 114 REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET Apply YAMAHA GREASE F 150G Order Job/Part Q’ty Remarks Bearing Rear wheel drive hub Rear wheel drive hub damper O-ring Oil seal Bearing Bearing Spacer For installation, reverse the removal pro- cedure.
  • Page 115: Removing The Rear Wheel

    REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET EAS00563 REMOVING THE REAR WHEEL 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the rear wheel is elevated.
  • Page 116: Checking The Rear Wheel Drive Hub

    REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET EAS00567 CHECKING THE REAR WHEEL DRIVE HUB 1. Check: • rear wheel drive hub Cracks/damage → Replace. • rear wheel drive hub dampers Damage/wear → Replace. EAS00568 CHECKING AND REPLACING THE REAR WHEEL SPROCKET 1.
  • Page 117: Checking The Brake

    REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET EAS00569 CHECKING THE BRAKE The following procedure applies to all of the brake shoes. 1. Check: • brake shoe lining Glazed areas → Repair. Sand the glazed areas with course sandpa- per.
  • Page 118: Assembling The Brake Shoe Plate

    REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET 4. Measure: • brake drum inside diameter a Out of specification → Replace the wheel. Brake drum inside diameter limit (maximum) 131.0 mm (5.16 in) 5. Check: • brake camshaft Damage/wear →...
  • Page 119: Installing The Rear Wheel And Rear Wheel Sprocket

    REAR WHEEL SPROCKET 1. Lubricate: • O-ring • oil seals Recommended lubricant YAMAHA GREASE F 150G 2. Install: • rear wheel sprocket 1 • lock washers 2 • rear wheel sprocket bolts 40 Nm (4.0 m · kg, 29 ft · lb)
  • Page 120 REAR WHEEL, BRAKE SHOE PLATE, AND CHAS REAR WHEEL SPROCKET 7. Install: • brake torque rod 19 Nm (1.9 m · kg, 13 ft · lb) 8. Adjust: • brake pedal free play Refer to “ADJUSTING THE REAR BRAKE” in chapter 3. 4 - 17...
  • Page 121: Front Brake

    CHAS FRONT BRAKE EAS00576 FRONT BRAKE FRONT BRAKE PADS 7 Nm (0.7 m kg, 5.1 ft • • 23 Nm (2.3 m kg, 17 ft • • Order Job/Part Q’ty Remarks Removing the front brake pads Remove the parts in the order listed. Brake hose holder Brake caliper bolt Brake caliper...
  • Page 122: Replacing The Front Brake Pads

    CHAS FRONT BRAKE EAS00579 CAUTION: Disc brake components rarely require dis- assembly. Therefore, always follow these preventive measures: • Never disassemble brake components unless absolutely necessary. • If any connection on the hydraulic brake system is disconnected, the entire brake system must be disassembled, drained, cleaned, properly filled, and bled after reassembly.
  • Page 123 CHAS FRONT BRAKE 2. Remove: • brake pads 1 • brake pad shim 2 • brake pad springs 3 3. Measure: • brake pad wear limit a Out of specification → Replace the brake pads as a set. Brake pad wear limit 0.8 mm (0.03 in) 4.
  • Page 124 CHAS FRONT BRAKE 5. Lubricate: • brake caliper dust boot 1 Recommended lubricant Lithium-soap-based grease CAUTION: • Do not allow grease to contact the brake pads. • Remove any excess grease. 6. Install: • brake caliper bolt 23 Nm (2.3 m · kg, 17 ft · lb) •...
  • Page 125: Front Brake Master Cylinder

    CHAS FRONT BRAKE EAS00584 FRONT BRAKE MASTER CYLINDER 10 Nm (1.0 m kg, 7.2 ft • • 10 Nm (1.0 m kg, 7.2 ft • • 26 Nm (2.6 m kg, 19 ft 10 Nm (1.0 m kg, 7.2 ft •...
  • Page 126 CHAS FRONT BRAKE 10 Nm (1.0 m kg, 7.2 ft • • 10 Nm (1.0 m kg, 7.2 ft • • 26 Nm (2.6 m kg, 19 ft 10 Nm (1.0 m kg, 7.2 ft • • • • Order Job/Part Q’ty Remarks...
  • Page 127: Disassembling The Front Brake Master Cylinder

    CHAS FRONT BRAKE EAS00585 Order Job/Part Q’ty Remarks Disassembling the front brake mas- Remove the parts in the order listed. ter cylinder Dust boot Circlip Brake master cylinder kit Brake master cylinder For assembly, reverse the disassembly procedure. 4 - 24...
  • Page 128: Checking The Front Brake Master Cylinder

    CHAS FRONT BRAKE EAS00588 DISASSEMBLING THE FRONT BRAKE MASTER CYLINDER NOTE: Before disassembling the front brake master cylinder, drain the brake fluid from the entire brake system. 1. Disconnect: • front brake light switch 1 NOTE: Push the fastener to remove the front brake light switch from the brake master cylinder.
  • Page 129: Assembling And Installing The Front Brake Master Cylinder

    CHAS FRONT BRAKE 3. Check: • brake master cylinder reservoir cap Cracks/damage → Replace. • brake master cylinder reservoir diaphragm • brake master cylinder reservoir diaphragm holder Damage/wear → Replace. 4. Check: • brake hose Cracks/damage/wear → Replace. EAS00598 ASSEMBLING AND INSTALLING THE FRONT BRAKE MASTER CYLINDER WARNING •...
  • Page 130 CHAS FRONT BRAKE 2. Install: • copper washers • brake hose • union bolt 26 Nm (2.6 m · kg, 19 ft · lb) WARNING Proper brake hose routing is essential to 40˚ ± 5˚ insure safe vehicle operation. Refer to “CABLE ROUTING”...
  • Page 131 CHAS FRONT BRAKE 4. Bleed: • brake system Refer to “BLEEDING THE HYDRAULIC BRAKE SYSTEM” in chapter 3. 5. Check: • brake fluid level Below the minimum level mark a → Add the recommended brake fluid to the proper level. Refer to “CHECKING THE BRAKE FLUID LEVEL”...
  • Page 132: Front Brake Caliper

    CHAS FRONT BRAKE EAS00612 FRONT BRAKE CALIPER 35 Nm (3.5 m kg, 25 ft • • 23 Nm (2.3 m kg, 17 ft • • 25 Nm (2.5 m kg, 18 ft • • Order Job/Part Q’ty Remarks Removing the front brake caliper Remove the parts in the order listed.
  • Page 133: Disassembling The Front Brake Caliper

    CHAS FRONT BRAKE EAS00614 Order Job/Part Q’ty Remarks Disassembling the front brake cali- Remove the parts in the order listed. Brake caliper bolt Brake caliper bracket Bleed screw Brake pad Brake pad shim Brake pad spring Brake caliper piston Refer to “DISASSEMBLING THE Dust boot FRONT BRAKE CALIPER”.
  • Page 134 CHAS FRONT BRAKE EAS00618 DISASSEMBLING THE FRONT BRAKE CALIPER NOTE: Before disassembling the brake caliper, drain the brake fluid from the entire brake system. 1. Loosen: • brake caliper bolt 1 2. Remove: • union bolt 2 • copper washers 3 •...
  • Page 135: Checking The Front Brake Caliper

    CHAS FRONT BRAKE EAS00630 CHECKING THE FRONT BRAKE CALIPER Recommended brake component replacement schedule Brake pads If necessary Piston seals Every two years Brake hose Every four years Every two years and whenever the Brake fluid brake is disassem- bled 1.
  • Page 136: Assembling And Installing The Front Brake Caliper

    CHAS FRONT BRAKE EAS00634 ASSEMBLING AND INSTALLING THE FRONT BRAKE CALIPER WARNING • Before installation, all internal brake com- ponents should be cleaned and lubricated with clean or new brake fluid. • Never use solvents on internal brake components as they will cause the piston seals to swell and distort.
  • Page 137 CHAS FRONT BRAKE 4. Install: • brake pad springs • brake pad shim • brake pads • brake caliper 23 Nm (2.3 m · kg, 17 ft · lb) Refer “REPLACING FRONT BRAKE PADS”. 5. Fill: • brake master cylinder reservoir (with the specified amount of the recom- mended brake fluid) Recommended brake fluid...
  • Page 138 CHAS FRONT BRAKE 7. Check: • brake fluid level Below the minimum level mark a → Add the recommended brake fluid to the proper level. Refer to “CHECKING THE BRAKE FLUID LEVEL” in chapter 3. 8. Check: • brake lever operation Soft or spongy feeling →...
  • Page 139: Front Fork

    CHAS FRONT FORK EAS00646 FRONT FORK 23 Nm (2.3 m kg, 17 ft • • 23 Nm (2.3 m kg, 17 ft • • 30 Nm (3.0 m kg, 22 ft • • 7 Nm (0.7 m kg, 5.1 ft •...
  • Page 140 CHAS FRONT FORK 23 Nm (2.3 m kg, 17 ft • • 23 Nm (2.3 m kg, 17 ft • • 30 Nm (3.0 m kg, 22 ft • • 7 Nm (0.7 m kg, 5.1 ft • • 10 Nm (1.0 m kg, 7.2 ft •...
  • Page 141 CHAS FRONT FORK EAS00648 23 Nm (2.3 m kg, 17 ft • • 23 Nm (2.3 m kg, 17 ft • • Order Job/Part Q’ty Remarks Disassembling the front fork legs Remove the parts in the order listed. The following procedure applies to both of the front fork legs.
  • Page 142 CHAS FRONT FORK EAS00648 23 Nm (2.3 m kg, 17 ft • • 23 Nm (2.3 m kg, 17 ft • • Order Job/Part Q’ty Remarks Damper rod Rebound spring Refer to “DISASSEMBLING THE Inner tube FRONT FORK LEGS” and “ASSEM- Oil flow stopper BLING THE FRONT FORK LEGS”.
  • Page 143: Removing The Front Fork Legs

    CHAS FRONT FORK EAS00651 REMOVING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs. 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the front wheel is elevated.
  • Page 144: Checking The Front Fork Legs

    CHAS FRONT FORK 3. Remove: • dust seal 1 • oil seal clip 2 (with a flat-head screwdriver) CAUTION: Do not scratch the inner tube. 4. Remove: • damper rod bolt 1 • copper washer NOTE: While holding the damper rod with the 14-mm hexagon nut/socket wrench 2 and T-handle 3, loosen the damper rod bolt.
  • Page 145: Assembling The Front Fork Legs

    CHAS FRONT FORK 3. Check: • damper rod 1 Damage/wear → Replace. Obstruction → Blow out all of the oil pas- sages with compressed air. • oil flow stopper 2 Damage → Replace. EAS00659 ASSEMBLING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs.
  • Page 146 CHAS FRONT FORK 3. Tighten: • damper rod bolt 1 23 Nm (2.3 m · kg, 17 ft · lb) ® LOCTITE NOTE: While holding the damper rod with the 14-mm hexagon nut/socket wrench 2 and T-handle 3, tighten the damper rod bolt. T-handle 90890-01326, YM-01326 4.
  • Page 147 Quantity (each front fork leg) 0.154 L (0.136 Imp qt, 0.163 US qt) Recommended oil Yamaha fork and shock oil 10W or equivalent Front fork leg oil level a (from the top of the inner tube, with the inner tube fully compressed and without the fork spring) 166 mm (6.54 in)
  • Page 148: Installing The Front Fork Legs

    CHAS FRONT FORK 8. Install: • fork spring 1 • spring seat 2 • spacer • O-ring • cap bolt NOTE: • Install the spring with the smaller pitch facing • Before installing the cap bolt, lubricate its O- ring with grease. •...
  • Page 149: Handlebar

    CHAS HANDLEBAR EAS00664 HANDLEBAR Order Job/Part Q’ty Remarks Removing the handlebar Remove the parts in the order listed. Rearview mirror (left and right) Plastic band Grip end Right handlebar switch Refer to “INSTALLING Throttle cable Disconnect. THE HANDLEBAR”. Throttle grip Front brake light switch Refer to “REMOVING THE HANDLE- BAR”.
  • Page 150 CHAS HANDLEBAR Order Job/Part Q’ty Remarks Left handlebar switch Refer to “INSTALLING THE HANDLE- BAR”. Handlebar grip Refer to “REMOVING THE HANDLE- BAR”. Clutch lever Clutch lever holder Refer to “INSTALLING THE HANDLE- Handlebar holder BAR”. Handlebar For installation, reverse the removal pro- cedure.
  • Page 151: Removing The Handlebar

    CHAS HANDLEBAR EAS00666 REMOVING THE HANDLEBAR 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. 2. Remove: • front brake light switch • clutch switch NOTE: •...
  • Page 152 CHAS HANDLEBAR 2. Install: • handlebar 1 • handlebar holders 2 23 Nm (2.3 m · kg, 17 ft · lb) CAUTION: • First, tighten the bolts on the front side of the handlebar holder, and then on the rear side.
  • Page 153 CHAS HANDLEBAR 5. Install: • left handlebar switch 1 NOTE: Align the projection a on the left handlebar switch with the hole b in the handlebar. 6. Install: • clutch cable NOTE: Lubricate the end of the clutch cable with a thin coat of lithium-soap-based grease.
  • Page 154 CHAS HANDLEBAR 10.Adjust: • throttle cable free play Refer to “ADJUSTING THE THROTTLE CABLE FREE PLAY” in chapter 3. Throttle cable free play (at the flange of the throttle grip) 3 ~ 7 mm (0.12 ~ 0.28 in) 4 - 51...
  • Page 155: Steering Head

    CHAS STEERING HEAD EAS00675 STEERING HEAD HEADLIGHT AND METER ASSEMBLY Order Job/Part Q’ty Remarks Removing the headlight and meter Remove the parts in the order listed. assembly Front wheel Refer to “FRONT WHEEL AND BRAKE DISC”. Front fork Refer to “FRONT FORK”. Handlebar Refer to “HANDLEBAR”.
  • Page 156 CHAS STEERING HEAD Order Job/Part Q’ty Remarks Bracket Front turn signal light assembly Main switch For installation, reverse the removal pro- cedure. 4 - 53...
  • Page 157: Lower Bracket

    CHAS STEERING HEAD LOWER BRACKET Order Job/Part Q’ty Remarks Removing the lower bracket Remove the parts in the order listed. Meter assembly/main switch Refer to “HEADLIGHT AND METER ASSEMBLY”. Steering stem nut Refer to “INSTALLING THE STEERING Upper bracket HEAD”. Lock washer Upper ring nut Refer to “REMOVING THE LOWER...
  • Page 158 CHAS STEERING HEAD Order Job/Part Q’ty Remarks Lower bearing outer race Refer to “INSTALLING THE STEERING HEAD”. Lower bearing inner race For installation, reverse the removal pro- cedure. 4 - 55...
  • Page 159: Removing The Lower Bracket

    CHAS STEERING HEAD EAS00677 REMOVING THE LOWER BRACKET 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. 2. Remove: • upper ring nut 1 • rubber washer •...
  • Page 160: Installing The Steering Head

    CHAS STEERING HEAD 3. Replace: • bearings • bearing races M MMM M MMM M MMM M MMM M MMM a. Remove the bearing races from the steering head pipe with a long rod 1 and hammer. b. Remove the bearing race from the lower bracket with a floor chisel 2 and hammer.
  • Page 161 CHAS STEERING HEAD 3. Install: • upper bracket • steering stem nut NOTE: Temporarily tighten the steering stem nut. 4. Install: • front fork legs Refer to “INSTALLING THE FRONT FORK LEGS”. NOTE: Temporarily tighten the upper and lower bracket pinch bolts. 5.
  • Page 162: Drive Chain And Drive Sprocket

    CHAS DRIVE CHAIN AND DRIVE SPROCKET EAS00700 DRIVE CHAIN AND DRIVE SPROCKET Order Job/Part Q’ty Remarks Removing the drive chain and drive Remove the parts in the order listed. sprocket Rear wheel Refer to “REAR WHEEL, BRAKE SHOE PLATE, AND REAR WHEEL SPROCKET”.
  • Page 163 CHAS DRIVE CHAIN AND DRIVE SPROCKET Order Job/Part Q’ty Remarks Drive sprocket holder Refer to “REMOVING THE DRIVE CHAIN” and “INSTALLING THE DRIVE Drive sprocket CHAIN”. For installation, reverse the removal pro- cedure. 4 - 60...
  • Page 164: Removing The Drive Chain

    CHAS DRIVE CHAIN AND DRIVE SPROCKET EAS00705 REMOVING THE DRIVE CHAIN 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the rear wheel is elevated.
  • Page 165 CHAS DRIVE CHAIN AND DRIVE SPROCKET 2. Check: • drive chain Stiffness → Clean and lubricate or replace. 3. Clean: • drive chain M MMM M MMM M MMM M MMM M MMM a. Wipe the drive chain with a clean cloth. b.
  • Page 166: Installing The Drive Chain

    CHAS DRIVE CHAIN AND DRIVE SPROCKET 6. Check: • drive sprocket • rear wheel sprocket More than 1/4 tooth a wear → Replace the drive chain, drive sprocket and rear wheel sprocket as a set. Bent teeth → Replace the drive chain, drive sprocket and rear wheel sprocket as a set.
  • Page 167 CHAS DRIVE CHAIN AND DRIVE SPROCKET 5. Tighten: • drive sprocket bolts 10 Nm (1.0 m · kg, 7.2 ft · lb) NOTE: Tighten the drive sprocket bolts while pressing the brake pedal. 6. Install: • drive sprocket cover 7 Nm (0.7 m · kg, 5.1 ft · lb) NOTE: Proper neutral switch lead routing is essential to insure safe vehicle operation.
  • Page 168: Rear Shock Absorber Assemblies And Swingarm

    REAR SHOCK ABSORBER ASSEMBLIES CHAS AND SWINGARM EAS00685 REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM Order Job/Part Q’ty Remarks Removing the rear shock absorber Remove the parts in the order listed. assemblies and swingarm Muffler assembly Refer to “ENGINE” in chapter 5. Rear wheel Refer to “REAR WHEEL, BRAKE SHOE PLATE, AND REAR WHEEL...
  • Page 169 REAR SHOCK ABSORBER ASSEMBLIES CHAS AND SWINGARM Order Job/Part Q’ty Remarks Rear shock absorber assembly Refer to “REMOVING THE REAR Pivot shaft nut SHOCK ABSORBER ASSEMBLIES Pivot shaft AND SWINGARM” and “INSTALLING THE REAR SHOCK ABSORBER Swingarm ASSEMBLIES AND SWINGARM”. Passenger footrest bracket (left and right) Dust cover...
  • Page 170: Removing The Rear Shock Absorber Assemblies And Swingarm

    REAR SHOCK ABSORBER ASSEMBLIES CHAS AND SWINGARM EAS00691/EAS00703 REMOVING THE REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM 1. Stand the vehicle on a level surface. WARNING Securely support the vehicle so that there is no danger of it falling over. NOTE: Place the vehicle on a suitable stand so that the rear wheel is elevated.
  • Page 171: Checking The Rear Shock Absorber Assemblies

    REAR SHOCK ABSORBER ASSEMBLIES CHAS AND SWINGARM 5. Remove: • pivot shaft nut • pivot shaft • swingarm • footrest bracket (left and right) EAS00695 CHECKING THE REAR SHOCK ABSORBER ASSEMBLIES The following procedure applies to both rear shock absorber assemblies. 1.
  • Page 172 REAR SHOCK ABSORBER ASSEMBLIES CHAS AND SWINGARM 3. Wash: • pivot shaft • dust covers • spacers • shim(s) • bearings Recommended cleaning solvent Kerosene 4. Check: • dust covers • spacers • shim(s) • bushings • oil seals Damage/wear → Replace. 5.
  • Page 173: Installing The Rear Shock Absorber Assemblies And Swingarm

    REAR SHOCK ABSORBER ASSEMBLIES CHAS AND SWINGARM NOTE: If adding an even number of shims, add the same number to both the left and right sides of the swingarm. If adding an odd number of shims, the left side of the swingarm should have one more shim than the right side.
  • Page 174: Eng

    CHAPTER 5 ENGINE ENGINE REMOVAL ..................5-1 MUFFLER ASSEMBLY ................5-1 CABLES, LEADS, HOSES AND FOOTREST...........5-2 ENGINE..................... 5-5 INSTALLING THE ENGINE............... 5-6 CYLINDER HEAD.................... 5-7 REMOVING THE CYLINDER HEAD............5-9 CHECKING THE CYLINDER HEAD ............5-10 CHECKING THE TAPPET COVERS AND CAMSHAFT SPROCKET COVER ....................5-11 CHECKING THE TIMING CHAIN TENSIONER........
  • Page 175 CLUTCH ......................5-35 CLUTCH COVER ..................5-35 CLUTCH ....................5-37 CLUTCH PUSH LEVER ................5-39 REMOVING THE CLUTCH ..............5-40 CHECKING THE FRICTION PLATES.............5-40 CHECKING THE CLUTCH PLATES ............5-41 CHECKING THE CLUTCH SPRINGS.............5-41 CHECKING THE CLUTCH HOUSING ............5-42 CHECKING THE CLUTCH BOSS............5-42 CHECKING THE PRESSURE PLATE ............5-42 CHECKING THE CLUTCH PUSH LEVER AND SHORT CLUTCH PUSH ROD.....................
  • Page 176 CRANKSHAFT ....................5-73 CRANKSHAFT AND BALANCER ............5-73 REMOVING THE CRANKSHAFT AND BALANCER ......5-74 CHECKING THE CRANKSHAFT ............5-75 INSTALLING THE CRANKSHAFT AND BALANCER ......5-76 TRANSMISSION.................... 5-77 CHECKING THE SHIFT FORKS............. 5-80 CHECKING THE SHIFT DRUM ..............5-80 CHECKING THE TRANSMISSION ............5-80 CHECKING THE LONG CLUTCH PUSH ROD........
  • Page 177: Engine

    ENGINE REMOVAL EAS00189 ENGINE ENGINE REMOVAL MUFFLER ASSEMBLY 22 Nm (2.2 m kg, 16 ft • • 8 Nm (0.8 m kg, 5.8 ft • • 10 Nm (1.0 m kg, 7.2 ft • • Order Job/Part Q’ty Remarks Removing the muffler assembly Remove the parts in the order listed.
  • Page 178: Cables, Leads, Hoses And Footrest

    ENGINE REMOVAL EAS00188 CABLES, LEADS, HOSES AND FOOTREST Apply sealant 10 Nm (1.0 m kg, 7.2 ft • • Yamaha bond No.1215 90890-85505 38 Nm (3.8 m kg, 27 ft • • 10 Nm (1.0 m kg, 7.2 ft •...
  • Page 179 ENGINE REMOVAL Apply sealant 10 Nm (1.0 m kg, 7.2 ft • • Yamaha bond No.1215 90890-85505 38 Nm (3.8 m kg, 27 ft • • 10 Nm (1.0 m kg, 7.2 ft • • 23 Nm (2.3 m kg, 17 ft •...
  • Page 180 ENGINE REMOVAL Apply sealant 10 Nm (1.0 m kg, 7.2 ft • • Yamaha bond No.1215 90890-85505 38 Nm (3.8 m kg, 27 ft • • 10 Nm (1.0 m kg, 7.2 ft • • 23 Nm (2.3 m kg, 17 ft •...
  • Page 181: Engine

    ENGINE REMOVAL EAS00191 ENGINE 38 Nm (3.8 m kg, 27 ft • • 55 Nm (5.5 m kg, 40 ft • • 38 Nm (3.8 m kg, 27 ft • • Order Job/Part Q’ty Remarks Removing the engine Remove the parts in the order listed. NOTE: Place a suitable stand under the engine.
  • Page 182: Installing The Engine

    ENGINE REMOVAL EAS00192 INSTALLING THE ENGINE 1. Install: • rear mounting bolt/nut 1 • left upper engine bracket 2 • right upper engine bracket 3 • upper engine bracket bolts/nuts 4 • upper mounting bolt/nut 5 • lower engine bracket 6 •...
  • Page 183: Cylinder Head

    CYLINDER HEAD EAS00221 CYLINDER HEAD Apply sealant Yamaha bond No.1215 90890-85505 Order Job/Part Q’ty Remarks Removing the cylinder head Remove the parts in the order listed. Side cover (left and right)/seat/fuel tank Refer to “SIDE COVERS, SEAT AND FUEL TANK” in chapter 3.
  • Page 184 CYLINDER HEAD Apply sealant Yamaha bond No.1215 90890-85505 Order Job/Part Q’ty Remarks Exhaust tappet cover Intake manifold Timing chain tensioner cap bolt Timing chain tensioner Refer to “REMOVING THE CYLINDER Timing chain tensioner gasket HEAD” and “INSTALLING THE CYLIN- DER HEAD”.
  • Page 185: Removing The Cylinder Head

    CYLINDER HEAD EAS00225 REMOVING THE CYLINDER HEAD 1. Align: • “I” mark a on the A.C. magneto rotor (with the stationary pointer b on the A.C. magneto rotor cover) M MMM M MMM M MMM M MMM M MMM a. Turn the crankshaft counterclockwise. b.
  • Page 186: Checking The Cylinder Head

    CYLINDER HEAD EAS00227 CHECKING THE CYLINDER HEAD 1. Eliminate: • combustion chamber carbon deposits (with a rounded scraper) NOTE: Do not use a sharp instrument to avoid damag- ing or scratching: • spark plug bore threads • valve seats 2. Check: •...
  • Page 187: Checking The Tappet Covers And Camshaft Sprocket Cover

    CYLINDER HEAD EAS00212 CHECKING THE TAPPET COVERS AND CAMSHAFT SPROCKET COVER The following procedure applies to both of the tappet covers and O-rings. 1. Check: • tappet covers • camshaft sprocket cover • O-rings Damage/wear → Replace the defective part(s). EAS00210 CHECKING THE TIMING CHAIN TENSIONER...
  • Page 188: Checking The Camshaft Sprocket

    CYLINDER HEAD CHECKING THE CAMSHAFT SPROCKET 1. Check: • camshaft sprocket Wear/damage → Replace the camshaft sprocket and timing chain as a set. a 1/4 of a tooth b Correct 1 Roller 2 Sprocket EAS00231 INSTALLING THE CYLINDER HEAD 1. Install: •...
  • Page 189 CYLINDER HEAD 5. Install: • camshaft sprocket 1 • timing chain 2 M MMM M MMM M MMM M MMM M MMM a. Check and adjust the “I” mark a on the A.C. magneto rotor with the stationary pointer b on the A.C. magneto rotor cover. b.
  • Page 190 CYLINDER HEAD 6. Install: • timing chain tensioner M MMM M MMM M MMM M MMM M MMM a. While lightly pressing the timing chain ten- sioner rod by hand, turn the tensioner rod fully clockwise with a thin screwdriver 1. NOTE: Make sure that the tensioner rod has been fully set clockwise.
  • Page 191 CYLINDER HEAD 9. Tighten: • camshaft sprocket bolt 20 Nm (2.0 m · kg, 14 ft · lb) CAUTION: Be sure to tighten the camshaft sprocket bolt to the specified torque to avoid the possibility of the bolt coming loose and damaging the engine.
  • Page 192: Rocker Arms And Camshaft

    ROCKER ARMS AND CAMSHAFT ROCKER ARMS AND CAMSHAFT Order Job/Part Q’ty Remarks Removing the rocker arms and cam- Remove the parts in the order listed. shaft Cylinder head Refer to “CYLINDER HEAD”. Locknut Loosen. Refer to “REMOVING Adjusting screw Loosen. THE ROCKER ARMS Camshaft retainer AND CAMSHAFT”...
  • Page 193: Removing The Rocker Arms And Camshaft

    ROCKER ARMS AND CAMSHAFT EAS00202 REMOVING THE ROCKER ARMS AND CAMSHAFT 1. Loosen: • locknuts • adjusting screws 2. Remove: • camshaft retainer 1 3. Remove: • intake rocker arm shaft • exhaust rocker arm shaft • intake rocker arm •...
  • Page 194: Checking The Rocker Arms And Rocker Arm Shafts

    ROCKER ARMS AND CAMSHAFT 2. Measure: • camshaft lobe dimensions a and b Out of specification → Replace the cam- shaft. Camshaft lobe dimensions Intake a 25.881 ~ 25.981 mm (1.0189 ~ 1.0229 in) <Limit>: 25.851 mm (1.0178 in) b 21.194 ~ 21.294 mm (0.8344 ~ 0.8383 in) <Limit>: 21.164 mm (0.8332 in) Exhaust...
  • Page 195: Installing The Rocker Arms And Camshaft

    ROCKER ARMS AND CAMSHAFT 3. Measure: • rocker arm inside diameter Out of specification → Replace. Rocker arm inside diameter 10.000 ~ 10.015 mm (0.3937 ~ 0.3943 in) <Limit>: 10.030 mm (0.3949 in) 4. Measure: • rocker arm shaft outside diameter Out of specification →...
  • Page 196 ROCKER ARMS AND CAMSHAFT 2. Install: • camshaft 3. Lubricate: • rocker arms • rocker arm shafts Recommended lubricant Rocker arm Molybdenum-disulfide grease Rocker arm shafts Engine oil 4. Install: • exhaust rocker arm 1 • exhaust rocker arm shaft 2 •...
  • Page 197: Valves And Valve Springs

    VALVES AND VALVE SPRINGS EAS00236 VALVES AND VALVE SPRINGS Order Job/Part Q’ty Remarks Removing the valves and valve Remove the parts in the order listed. springs Cylinder head Refer to “CYLINDER HEAD”. Rocker arms/rocker arm shafts/cam- Refer to “ROCKER ARMS AND CAM- shaft SHAFT”.
  • Page 198: Removing The Valves

    VALVES AND VALVE SPRINGS EAS00237 REMOVING THE VALVES The following procedure applies to all of the valves and related components. NOTE: Before removing the internal parts of the cylin- der head (e.g., valves, valve springs, valve seats), make sure the valves properly seal. 1.
  • Page 199: Checking The Valves And Valve Guides

    VALVES AND VALVE SPRINGS EAS00239 CHECKING THE VALVES AND VALVE GUIDES The following procedure applies to all of the valves and valve guides. 1. Measure: • valve-stem-to-valve-guide clearance Valve-stem-to-valve-guide clearance = Valve guide inside diameter a – Valve stem diameter b Out of specification →...
  • Page 200 VALVES AND VALVE SPRINGS c. After installing the valve guide, bore the valve guide with the valve guide reamer 3 to obtain the proper valve-stem-to-valve- guide clearance. NOTE: After replacing the valve guide, reface the valve seat. Valve guide remover (ø5) 90890-04097, YM-04097 Valve guide installer (ø5) 90890-04098, YM-04098...
  • Page 201: Checking The Valve Seats

    VALVES AND VALVE SPRINGS 6. Measure: • valve stem runout Out of specification → Replace the valve. NOTE: • When installing a new valve, always replace the valve guide. • If the valve is removed or replaced, always replace the valve stem seal. Valve stem runout 0.010 mm (0.0004 in) EAS00240...
  • Page 202 VALVES AND VALVE SPRINGS 4. Lap: • valve face • valve seat NOTE: After replacing the cylinder head or replacing the valve and valve guide, the valve seat and valve face should be lapped. M MMM M MMM M MMM M MMM M MMM a.
  • Page 203: Checking The Valve Springs

    VALVES AND VALVE SPRINGS EAS00241 CHECKING THE VALVE SPRINGS The following procedure applies to all of the valve springs. 1. Measure: • valve spring free length a Out of specification → Replace the valve spring. Valve spring free length 47.06 mm (1.85 in) <Limit>: 44.71 mm (1.76 in) 2.
  • Page 204 VALVES AND VALVE SPRINGS 2. Lubricate: • valve stem 1 • valve stem seal 2 (with the recommended lubricant) Recommended lubricant Engine oil 3. Install: • valve 1 • valve spring seat 2 (into the cylinder head) • valve stem seal 3 •...
  • Page 205: Cylinder And Piston

    CYLINDER AND PISTON EAS00251 CYLINDER AND PISTON Order Job/Part Q’ty Remarks Removing the cylinder and piston Remove the parts in the order listed. Cylinder head Refer to “CYLINDER HEAD”. Timing chain guide (exhaust) Cylinder O-ring Refer to “INSTALLING THE PISTON Cylinder gasket AND CYLINDER”.
  • Page 206: Removing The Cylinder And Piston

    CYLINDER AND PISTON EAS00253 REMOVING THE CYLINDER AND PISTON 1. Remove: • piston pin clips 1 • piston pin 2 • piston 3 CAUTION: Do not use a hammer to drive the piston pin out. NOTE: • Before removing the piston pin clip, cover the crankcase opening with a clean rag to pre- vent the piston pin clip from falling into the crankcase.
  • Page 207 CYLINDER AND PISTON 2. Measure: • piston-to-cylinder clearance M MMM M MMM M MMM M MMM M MMM a. Measure cylinder bore “C” with the cylinder bore gauge 1. a 40 mm (1.57 in) from the top of the cylinder NOTE: Measure cylinder bore “C”...
  • Page 208: Checking The Piston Rings

    CYLINDER AND PISTON EAS00263 CHECKING THE PISTON RINGS 1. Measure: • piston ring side clearance Out of specification → Replace the piston and piston rings as a set. NOTE: Before measuring the piston ring side clear- ance, eliminate any carbon deposits from the piston ring grooves and piston rings.
  • Page 209: Checking The Piston Pin

    CYLINDER AND PISTON EAS00265 CHECKING THE PISTON PIN 1. Check: • piston pin Blue discoloration/grooves → Replace the piston pin and then check the lubrication system. 2. Measure: • piston pin outside diameter a Out of specification → Replace the piston pin.
  • Page 210 CYLINDER AND PISTON 2. Install: • piston 1 • piston pin 2 • piston pin clips 3 NOTE: • Apply engine oil onto the piston pin. • Make sure the arrow mark a on the piston points towards the exhaust side of the cylin- der.
  • Page 211: Clutch

    CLUTCH EAS00273 CLUTCH CLUTCH COVER 50 Nm (5.0 m kg, 36 ft • • 10 Nm (1.0 m kg, 7.2 ft • • Order Job/Part Q’ty Remarks Removing the clutch cover Remove the parts in the order listed. Engine oil Drain.
  • Page 212: Clutch

    CLUTCH 50 Nm (5.0 m kg, 36 ft • • 10 Nm (1.0 m kg, 7.2 ft • • Order Job/Part Q’ty Remarks Kickstarter lever Clutch cover Refer to “REMOVING THE CLUTCH” and “INSTALLING THE CLUTCH”. Clutch cover gasket Dowel pin Clutch cable Disconnect.
  • Page 213 CLUTCH EAS00274 CLUTCH 60 Nm (6.0 m kg, 43 ft • • 6 Nm (0.6 m kg, 4.3 ft • • 8 Nm (0.8 m kg, 5.8 ft • • 70 Nm (7.0 m kg, 50 ft • • Order Job/Part Q’ty Remarks...
  • Page 214 CLUTCH 60 Nm (6.0 m kg, 43 ft • • 6 Nm (0.6 m kg, 4.3 ft • • 8 Nm (0.8 m kg, 5.8 ft • • 70 Nm (7.0 m kg, 50 ft • • Order Job/Part Q’ty Remarks Primary drive gear nut Washer...
  • Page 215: Clutch Push Lever

    CLUTCH CLUTCH PUSH LEVER Order Job/Part Q’ty Remarks Removing the clutch push lever Remove the parts in the order listed. Clutch push lever Refer to “INSTALLING THE CLUTCH”. Clutch push lever spring Circlip Oil seal For installation, reverse the removal pro- cedure.
  • Page 216: Removing The Clutch

    CLUTCH EAS00277 REMOVING THE CLUTCH 1. Remove: • clutch cover NOTE: Loosen each bolt 1/4 of a turn at a time, in stages and in a crisscross pattern. After all of the bolts are fully loosened, remove them. 2. Loosen: •...
  • Page 217: Checking The Clutch Plates

    CLUTCH 2. Measure: • friction plate thickness Out of specification → Replace the friction plates as a set. NOTE: Measure the friction plate at four places. Friction plate thickness 3.00 mm (0.118 in) <Limit>: 2.80 mm (0.110 in) EAS00281 CHECKING THE CLUTCH PLATES The following procedure applies to all of the clutch plates.
  • Page 218: Checking The Clutch Housing

    CLUTCH 2. Measure: • clutch spring free length a Out of specification → Replace the clutch springs as a set. Clutch spring free length 29.30 mm (1.15 in) <Limit>: 27.84 mm (1.10 in) EAS00284 CHECKING THE CLUTCH HOUSING 1. Check: •...
  • Page 219: Checking The Primary Drive Gear And Primary Driven Gear

    CLUTCH EAS00292 CHECKING THE PRIMARY DRIVE GEAR AND PRIMARY DRIVEN GEAR 1. Check: • primary drive gear 1 • primary driven gear 2 (on the clutch housing) Damage/wear → Replace the primary drive gear and clutch housing as a set. →...
  • Page 220 CLUTCH 3. Install: • clutch boss • lock washer • clutch boss nut 1 NOTE: Lubricate the crankshaft end threads with engine oil. 4. Tighten: • clutch boss nut 60 Nm (6.0 m · kg, 43 ft · lb) NOTE: While holding the clutch boss 2 with the uni- versal clutch holder 3, tighten the clutch boss nut.
  • Page 221 CLUTCH 8. Install: • friction plates • clutch plates NOTE: First, install a friction plate and then alternate between a clutch plate and a friction plate. 9. Install: • pressure plate 1 • clutch springs 2 • clutch spring bolts 3 6 Nm (0.6 m ·...
  • Page 222 CLUTCH 12.Install: • kickstarter lever 1 50 Nm (5.0 m · kg, 36 ft · lb) NOTE: Install the kickstarter lever as close as possible to the clutch cover, making sure that the lever does not contact the area a of the clutch cover.
  • Page 223: Shift Shaft And Stopper Lever

    SHIFT SHAFT AND STOPPER LEVER EAS00327 SHIFT SHAFT AND STOPPER LEVER 10 Nm (1.0 m kg, 7.2 ft • • 12 Nm (1.2 m kg, 8.7 ft • • 10 Nm (1.0 m kg, 7.2 ft • • Order Job/Part Q’ty Remarks Removing the shift shaft and stop-...
  • Page 224: Checking The Shift Shaft

    SHIFT SHAFT AND STOPPER LEVER EAS00328 CHECKING THE SHIFT SHAFT 1. Check: • shift shaft • shift lever Bends/damage/wear → Replace. • shift lever spring Damage/wear → Replace. EAS00330 CHECKING THE STOPPER LEVER 1. Check: • stopper lever Bends/damage → Replace. Roller turns roughly →...
  • Page 225 SHIFT SHAFT AND STOPPER LEVER 2. Install: • shift shaft spring • circlip • shift shaft 1 NOTE: • Lubricate the oil seal lips with lithium-soap- based grease. • Hook the end of the shift shaft spring onto the shift shaft spring stopper 2. 3.
  • Page 226: Kickstarter

    KICKSTARTER EAS00338 KICKSTARTER Order Job/Part Q’ty Remarks Removing the kickstarter Remove the parts in the order listed. Clutch housing Refer to “CLUTCH”. Kickstarter assembly Refer to “INSTALLING THE KICK- STARTER”. Circlip Washer Kickstarter idle gear Washer Circlip For installation, reverse the removal pro- cedure.
  • Page 227 KICKSTARTER Order Job/Part Q’ty Remarks Disassembling the kickstarter Remove the parts in the order listed. Spacer Kickstarter spring Washer Kickstarter gear Kickstarter gear clip Kickstarter shaft For assembly, reverse the disassembly procedure. 5 - 51...
  • Page 228: Checking The Kickstarter

    KICKSTARTER EAS00339 CHECKING THE KICKSTARTER 1. Check: • kickstarter idle gear • kickstarter gear Damage/wear → Replace. 2. Check: • kickstarter spring Damage/wear → Replace. 3. Measure: • kickstarter gear clip force (with the spring gauge) Out of specification → Replace the kick- starter gear clip.
  • Page 229: Starter Clutch And A.c. Magneto Rotor

    STARTER CLUTCH AND A.C. MAGNETO ROTOR EAS00343 STARTER CLUTCH AND A.C. MAGNETO ROTOR Apply sealant Yamaha bond No.1215 90890-85505 Order Job/Part Q’ty Remarks Removing the starter clutch and Remove the parts in the order listed. A.C. magneto rotor Engine oil Refer to “CHANGING THE ENGINE OIL”...
  • Page 230 STARTER CLUTCH AND A.C. MAGNETO ROTOR Apply sealant Yamaha bond No.1215 90890-85505 Order Job/Part Q’ty Remarks A.C. magneto rotor cover gasket Dowel pin Pickup coil Refer to “INSTALLING THE A.C. MAG- Stator coil lead holder NETO ROTOR”. Stator coil A.C. magneto rotor Refer to “REMOVING THE A.C.
  • Page 231 STARTER CLUTCH AND A.C. MAGNETO ROTOR Apply sealant Yamaha bond No.1215 90890-85505 Order Job/Part Q’ty Remarks Starter clutch idle gear holder Starter clutch idle gear Starter clutch idle gear shaft For installation, reverse the removal pro- cedure. 5 - 55...
  • Page 232: Removing The A.c. Magneto Rotor

    STARTER CLUTCH AND A.C. MAGNETO ROTOR EAS00347 REMOVING THE A.C. MAGNETO ROTOR 1. Remove: • A.C. magneto cover NOTE: Loosen each bolt 1/4 of a turn at a time, in stages and in a crisscross pattern. After all of the bolts are fully loosened, remove them. 2.
  • Page 233: Removing The Starter Clutch

    STARTER CLUTCH AND A.C. MAGNETO ROTOR REMOVING THE STARTER CLUTCH 1. Remove: • starter clutch NOTE: • While holding the A.C. magneto rotor with the sheave holder, remove the starter clutch bolts 1. • Do not allow the sheave holder to touch the projection on the A.C.
  • Page 234: Installing The Starter Clutch

    STARTER CLUTCH AND A.C. MAGNETO ROTOR 4. Check: • starter clutch operation È M MMM M MMM M MMM M MMM M MMM a. Install the starter clutch gear 1 onto the starter clutch 2 and hold the starter clutch. b.
  • Page 235: Installing The A.c. Magneto Rotor

    3, tighten the A.C. mag- neto rotor bolt. • Do not allow the sheave holder to touch the projection on the A.C. magneto rotor. Sheave holder 90890-01701, YS-01880-A 3. Apply: • sealant 1 (into the slits) Yamaha bond No. 1215 90890-85505 5 - 59...
  • Page 236 STARTER CLUTCH AND A.C. MAGNETO ROTOR 4. Install: • stator coil 10 Nm (1.0 m · kg, 7.2 ft · lb) • stator coil lead holder 7 Nm (0.7 m · kg, 5.1 ft · lb) • pickup coil 10 Nm (1.0 m · kg, 7.2 ft · lb) 5.
  • Page 237: Oil Pump

    OIL PUMP EAS00360 OIL PUMP 7 Nm (0.7 m kg, 5.1 ft • • Order Job/Part Q’ty Remarks Removing the oil pump Remove the parts in the order listed. Clutch housing/primary drive gear Refer to “CLUTCH”. Rotary filter Refer to “INSTALLING THE ROTARY FILTER”.
  • Page 238 OIL PUMP 5 Nm (0.5 m kg, 3.6 ft • • Order Job/Part Q’ty Remarks Disassembling the oil pump Remove the parts in the order listed. Circlip Washer Spring washer Oil pump driven gear Dowel pin Washer Refer to “ASSEMBLING THE OIL Oil pump housing cover PUMP”.
  • Page 239: Checking The Oil Pump

    OIL PUMP EAS00364 CHECKING THE OIL PUMP 1. Check: • oil pump drive gear • oil pump driven gear • oil pump housing • oil pump housing cover Cracks/damage/wear → Replace the defec- tive part(s). 2. Measure: • inner-rotor-to-outer-rotor-tip clearance a •...
  • Page 240: Checking The Rotary Filter

    OIL PUMP EAS00371 CHECKING THE ROTARY FILTER 1. Check: • rotary filter Cracks/damage/wear → Replace. Contaminants → Clean with engine oil. EAS00375 ASSEMBLING THE OIL PUMP 1. Lubricate: • inner rotor • outer rotor • oil pump shaft (with the recommended lubricant) Recommended lubricant Engine oil 2.
  • Page 241: Installing The Oil Pump

    OIL PUMP EAS00376 INSTALLING THE OIL PUMP 1. Install: • oil pump gasket 1 • oil pump 7 Nm (0.7 m · kg, 5.1 ft · lb) CAUTION: After tightening the bolts, make sure the oil pump turns smoothly. NOTE: Install the oil pump gasket as shown in the illustration.
  • Page 242: Crankcase

    10 Nm (1.0 m kg, 7.2 ft • • 10 Nm (1.0 m kg, 7.2 ft • • ∗ Apply sealant Yamaha bond No.1215 ∗ 90890-85505 4 Nm (0.4 m kg, 2.9 ft 10 Nm (1.0 m kg, 7.2 ft • • •...
  • Page 243 10 Nm (1.0 m kg, 7.2 ft • • 10 Nm (1.0 m kg, 7.2 ft • • ∗ Apply sealant Yamaha bond No.1215 ∗ 90890-85505 4 Nm (0.4 m kg, 2.9 ft 10 Nm (1.0 m kg, 7.2 ft • • •...
  • Page 244: Crankcase Bearings

    CRANKCASE CRANKCASE BEARINGS 7 Nm (0.7 m kg, 5.1 ft • • Order Job/Part Q’ty Remarks Removing the crankcase bearings Remove the parts in the order listed. Crankshaft/balancer shaft Refer to “CRANKSHAFT”. Transmission Refer to “TRANSMISSION”. Oil seal Bearing retainer Bearing For installation, reverse the removal pro- cedure.
  • Page 245: Separating The Crankcase

    CRANKCASE SEPARATING THE CRANKCASE 1. Separate: • right crankcase 1 • left crankcase 2 M MMM M MMM M MMM M MMM M MMM a. Remove the crankcase bolts. NOTE: • Loosen each bolt 1/4 of a turn at a time and after all the bolts are loosened, remove them.
  • Page 246: Checking The Timing Chain And Timing Chain Guide

    CRANKCASE EAS00207 CHECKING THE TIMING CHAIN AND TIMING CHAIN GUIDE 1. Check: • timing chain Damage/stiffness → Replace the timing chain and camshaft sprocket as a set. 2. Check: • timing chain guide (intake side) Damage/wear → Replace. EAS00401 CHECKING THE BEARINGS AND OIL SEALS 1.
  • Page 247 CRANKCASE 4. Apply: • sealant 1 (to the mating surfaces of both crankcase halves) Yamaha bond No. 1215 90890-85505 NOTE: Do not allow any sealant to come into contact with the oil gallery. 5. Fit the right crankcase onto the left crank- case.
  • Page 248 CRANKCASE 8. Apply: • 4-stroke engine oil (to the crankshaft pin, bearing, and oil deliv- ery hole) 9. Check: • crankshaft and transmission operation Unsmooth operation → Repair. 5 - 72...
  • Page 249: Crankshaft

    CRANKSHAFT EAS00381 CRANKSHAFT CRANKSHAFT AND BALANCER Order Job/Part Q’ty Remarks Removing the crankshaft and bal- Remove the parts in the order listed. ancer Crankcase Separate. Refer to “CRANKCASE”. Balancer Refer to “REMOVING THE CRANK- SHAFT AND BALANCER” and Crankshaft “INSTALLING THE CRANKSHAFT AND BALANCER”.
  • Page 250: Removing The Crankshaft And Balancer

    CRANKSHAFT EAS00388 REMOVING THE CRANKSHAFT AND BALANCER 1. Remove: • balancer 1 NOTE: Align the punch mark a on the balancer driven gear with the punch mark b on the balancer drive gear, and then remove the balancer shaft. 2. Remove: •...
  • Page 251: Checking The Crankshaft

    CRANKSHAFT EAS00394 CHECKING THE CRANKSHAFT 1. Measure: • crankshaft runout C Out of specification → Replace the crank- shaft, bearing or both. NOTE: Turn the crankshaft slowly. Maximum crankshaft runout 0.030 mm (0.0012 in) 2. Measure: • big end side clearance D Out of specification →...
  • Page 252: Installing The Crankshaft And Balancer

    CRANKSHAFT EAS00408 INSTALLING THE CRANKSHAFT AND BALANCER 1. Install: • crankshaft 1 NOTE: Install the crankshaft with the crankshaft installer pot, crankshaft installer bolt, adapter (M12) and spacer. Crankshaft installer pot 2 90890-01274, YU-90058, YU-90059 Crankshaft installer bolt 3 90890-01275, YU-90060 Adapter (M12) 4 90890-01278, YU-90063 Spacer (crankshaft installer) 5...
  • Page 253: Transmission

    TRANSMISSION EAS00419 TRANSMISSION Order Job/Part Q’ty Remarks Removing the transmission, shift Remove the parts in the order listed. drum, and shift forks Crankcase Separate. Refer to “CRANKCASE”. Long shift fork guide bar Short shift fork guide bar Shift fork “R” Shift fork “L”...
  • Page 254 TRANSMISSION Order Job/Part Q’ty Remarks Disassembling the main axle Remove the parts in the order listed. 5th pinion gear Refer to “ASSEMBLING THE MAIN AXLE AND DRIVE AXLE”. 2nd pinion gear 3rd pinion gear Circlip Refer to “ASSEMBLING THE MAIN AXLE AND DRIVE AXLE”.
  • Page 255 TRANSMISSION Order Job/Part Q’ty Remarks Disassembling the drive axle Remove the parts in the order listed. 5th wheel gear 2nd wheel gear Circlip Refer to “ASSEMBLING THE MAIN AXLE AND DRIVE AXLE”. Washer 1st wheel gear 4th wheel gear Circlip Refer to “ASSEMBLING THE MAIN AXLE AND DRIVE AXLE”.
  • Page 256: Checking The Shift Forks

    TRANSMISSION EAS00421 CHECKING THE SHIFT FORKS The following procedure applies to all of the shift forks. 1. Check: • shift fork cam follower 1 • shift fork pawl 2 Bends/damage/scoring/wear → Replace the shift fork. 2. Check: • shift fork guide bar Roll the shift fork guide bar on a flat surface.
  • Page 257: Checking The Long Clutch Push Rod

    TRANSMISSION 2. Measure: • drive axle runout (with a centering device and dial gauge 1) Out of specification → Replace the drive axle. Drive axle runout limit 0.03 mm (0.0012 in) 3. Check: • transmission gears Blue discoloration/pitting/wear → Replace the defective gear(s).
  • Page 258: Assembling The Main Axle And Drive Axle

    TRANSMISSION EBS00355 ASSEMBLING THE MAIN AXLE AND DRIVE AXLE 1. Install: • washer 1 • circlip 2 NOTE: • Be sure the circlip sharp-edged corner a is positioned opposite side to the toothed washer and gear. • Be sure the circlip end b is positioned at axle spline groove c.
  • Page 259 TRANSMISSION 2. Check: • transmission Rough movement → Repair. NOTE: • Apply engine oil to each gear, shaft, and bearing thoroughly. • Before assembling the crankcase, make sure that the transmission is in neutral and that the gears turn freely. 5 - 83...
  • Page 260: Carb

    CARB CHAPTER 6 CARBURETOR CARBURETOR....................6-1 CHECKING THE CARBURETOR ............. 6-4 ASSEMBLING THE CARBURETOR............6-5 INSTALLING THE CARBURETOR ............6-7 MEASURING AND ADJUSTING THE FUEL LEVEL ........6-7 CHECKING THE FUEL COCK..............6-8 AIR INDUCTION SYSTEM ................6-9 AIR INJECTION..................6-9 AIR CUT-OFF VALVE ................6-9 AIR INDUCTION SYSTEM DIAGRAMS..........
  • Page 261: Carburetor

    CARB EAS00480 CARBURETOR CARBURETOR 6 - 1...
  • Page 262: Checking The Carburetor

    CARB CARBURETOR EAS00485 CHECKING THE CARBURETOR 1. Check: • carburetor body • float chamber • jet housing Cracks/damage → Replace. 2. Check: • fuel passages Obstruction → Clean. M MMM M MMM M MMM M MMM M MMM a. Wash the carburetor in a petroleum-based solvent.
  • Page 263: Assembling The Carburetor

    CARB CARBURETOR 10.Check: • coasting enricher diaphragm • spring • coasting enricher diaphragm cover Tears/damage → Replace. 11.Check: • jet needle kit 1 • pilot screw 2 • pilot jet 3 • main jet 4 • needle jet holder 5 •...
  • Page 264 CARB CARBURETOR 1. Install: • pilot screw 1 Pilot screw setting 1-1/2 turns out 2. Install: • needle valve seat 1 • needle valve seat holder 2 NOTE: Install the needle valve seat holder with its bent ends a facing downwards as shown. 3.
  • Page 265: Installing The Carburetor

    CARB CARBURETOR EAS00492 INSTALLING THE CARBURETOR 1. Adjust: • engine idling speed Engine idling speed 1,400 ~ 1,500 r/min Refer “ADJUSTING ENGINE IDLING SPEED” in chapter 3. 2. Adjust: • throttle cable free play Throttle cable free play (at the flange of the throttle grip) 3 ~ 7 mm (0.12 ~ 0.28 in) Refer to “ADJUSTING THE THROTTLE...
  • Page 266: Checking The Fuel Cock

    CARB CARBURETOR 2. Adjust: • fuel level M MMM M MMM M MMM M MMM M MMM a. Remove the carburetor. b. Check the needle valve seat and needle valve. c. If either is worn, replace them as a set. d.
  • Page 267: Air Induction System

    CARB AIR INDUCTION SYSTEM EAS00507 AIR INDUCTION SYSTEM AIR INJECTION The air induction system burns unburned exhaust gases by injecting fresh air (second- ary air) into the exhaust port, reducing the emission of hydrocarbons. When there is negative pressure at the exhaust port, the reed valve opens, allowing secondary air to flow into the exhaust port.
  • Page 268: Air Induction System Diagrams

    CARB AIR INDUCTION SYSTEM EAS00509 AIR INDUCTION SYSTEM DIAGRAMS 1 Air filter case 2 Air cut-off valve assembly 3 Intake manifold 6 - 10...
  • Page 269: Air Cut-Off Valve Assembly

    CARB AIR INDUCTION SYSTEM AIR CUT-OFF VALVE ASSEMBLY 6 - 11...
  • Page 270: Checking The Air Induction System

    CARB AIR INDUCTION SYSTEM EAS00510 CHECKING THE AIR INDUCTION SYSTEM 1. Check: • hoses Loose connection → Connect properly. Cracks/damage → Replace. • pipes Cracks/damage → Replace. 2. Check: • air cut-off valve Cracks/damage → Replace. 6 - 12...
  • Page 271: Elec

    – ELEC CHAPTER 7 ELECTRICAL SYSTEM ELECTRICAL COMPONENTS................ 7-1 CHECKING SWITCH CONTINUITY..............7-2 CHECKING THE SWITCHES................7-3 CHECKING THE BULBS AND BULB SOCKETS .......... 7-4 TYPES OF BULBS ..................7-4 CHECKING THE CONDITION OF THE BULBS ........7-5 CHECKING THE CONDITION OF THE BULB SOCKETS .......7-6 IGNITION SYSTEM ..................
  • Page 272: Electrical System

    – ELEC ELECTRICAL COMPONENTS EAS00729 ELECTRICAL SYSTEM ELECTRICAL COMPONENTS 1 Main switch 8 Starter relay E Diode 2 C.D.I. unit 9 Fuse F Ignition coil 3 Fuel sender 0 Rear brake light switch G Spark plug cap 4 Rectifier/regulator A Positive battery lead H Horn 5 Thermo switch B Battery...
  • Page 273: Checking Switch Continuity

    – ELEC CHECKING SWITCH CONTINUITY EAS00730 CHECKING SWITCH CONTINUITY Check each switch for continuity with the pocket tester. If the continuity reading is incor- rect, check the wiring connections and if nec- essary, replace the switch. CAUTION: Never insert the tester probes into the cou- pler terminal slots a.
  • Page 274: Checking The Bulbs And Bulb Sockets

    – ELEC CHECKING THE BULBS AND BULB SOCKETS EAS00732 CHECKING THE BULBS AND BULB SOCKETS Check each bulb and bulb socket for damage or wear, proper connections, and also for con- tinuity between the terminals. Damage/wear → Repair or replace the bulb, bulb socket or both.
  • Page 275: Checking The Condition Of The Bulbs

    – ELEC CHECKING THE BULBS AND BULB SOCKETS CHECKING THE CONDITION OF THE BULBS The following procedure applies to all of the bulbs. 1. Remove: • bulb WARNING Since the headlight bulb gets extremely hot, keep flammable products and your hands away from the bulb until it has cooled down.
  • Page 276: Checking The Condition Of The Bulb Sockets

    – ELEC CHECKING THE BULBS AND BULB SOCKETS CHECKING THE CONDITION OF THE BULB SOCKETS The following procedure applies to all of the bulb sockets. 1. Check: • bulb socket (for continuity) (with the pocket tester) No continuity → Replace. Pocket tester 90890-03112, YU-03112-C NOTE:...
  • Page 277: Ignition System

    – ELEC IGNITION SYSTEM EAS00734 IGNITION SYSTEM CIRCUIT DIAGRAM 7 - 7 L R Dg DgDgDg...
  • Page 278 – ELEC IGNITION SYSTEM EAS00746 EAS00748 6. Ignition coil resistance 7. Pickup coil resistance • Disconnect the ignition coil connector from • Disconnect the pickup coil coupler from the ignition coil terminal. the wire harness. • Connect the pocket tester (Ω × 1) to the •...
  • Page 279 – ELEC IGNITION SYSTEM EAS00754 9. Wiring • Check the entire ignition system’s wiring. Refer to “CIRCUIT DIAGRAM”. • Is the ignition system’s wiring properly connected and without defects? Replace the C.D.I. Properly connect or unit. repair ignition system’s wiring. 7 - 11...
  • Page 280: Electric Starting System

    – ELEC ELECTRIC STARTING SYSTEM EAS00755 ELECTRIC STARTING SYSTEM CIRCUIT DIAGRAM 7 - 12...
  • Page 281 – ELEC ELECTRIC STARTING SYSTEM EAS00761 EAS00760 4. Starter relay 5. Diode • Remove the starter relay. • Remove the diode from the coupler. • Connect the pocket tester (Ω × 1) and bat- • Connect the pocket tester (Ω × 1) to the tery (12 V) to the starter relay terminals as diode terminals as shown.
  • Page 282 – ELEC ELECTRIC STARTING SYSTEM EAS00749 EAS00764 6. Main switch 9. Start switch • Check the main switch for continuity. • Check the start switch for continuity. Refer to “CHECKING THE SWITCHES”. Refer to “CHECKING THE SWITCHES”. • Is the main switch OK? •...
  • Page 283: Starter Motor

    – ELEC STARTER MOTOR EAS00767 STARTER MOTOR Order Job/Part Q’ty Remarks Removing the starter motor Remove the parts in the order listed. Starter motor Starter motor lead Disconnect. NOTE: Pull out the starter motor before discon- necting the starter motor lead. For installation, reverse the removal pro- cedure.
  • Page 284 – ELEC STARTER MOTOR Order Job/Part Q’ty Remarks Disassembling the starter motor Remove the parts in the order listed. Front bracket O-ring Lock washer Shim Circlip Refer to “ASSEMBLING THE STARTER Oil seal MOTOR”. Bearing Rear bracket Brush set Armature assembly Starter motor yoke For assembly, reverse the disassembly procedure.
  • Page 285: Checking The Starter Motor

    – ELEC STARTER MOTOR EAS00770 CHECKING THE STARTER MOTOR 1. Check: • commutator Dirt → Clean with 600 grit sandpaper. 2. Measure: • commutator diameter a Out of specification → Replace the starter motor. Commutator wear limit 21.0 mm (0.83 in) 3.
  • Page 286: Charging System

    – ELEC CHARGING SYSTEM EAS00774 EAS00738 TROUBLESHOOTING 1. Fuse The battery is not being charged. • Check the fuse for continuity. Refer to “CHECKING THE FUSE” in chap- Check: ter 3. 1. fuse • Is the fuse OK? 2. battery 3.
  • Page 287 – ELEC CHARGING SYSTEM EAS00775 EAS00776 3. Charging voltage 4. Charging coil resistance • Connect the pocket tester (DC 20 V) to the • Disconnect the A.C.magneto coupler from battery as shown. the wire harness. • Connect the pocket tester (Ω × 1) to the Positive tester probe →...
  • Page 288: Circuit Diagram

    – ELEC LIGHTING SYSTEM EAS00780 LIGHTING SYSTEM CIRCUIT DIAGRAM 7 - 24...
  • Page 289 – ELEC LIGHTING SYSTEM EAS00784 6. Headlight relay 4. Dimmer switch • Remove the headlight relay. • Connect the pocket tester (Ω × 1) and bat- • Check the dimmer switch for continuity. Refer to “CHECKING THE SWITCHES”. tery (12 V) to the headlight relay terminals •...
  • Page 290: Checking The Lighting System

    – ELEC LIGHTING SYSTEM EAS00787 EAS00788 CHECKING THE LIGHTING SYSTEM 7. Wiring 1. The headlight and the high beam indicator • Check the entire lighting system’s wiring. light fail to come on. Refer to “CIRCUIT DIAGRAM”. 1. Headlight bulb and socket •...
  • Page 291 – ELEC LIGHTING SYSTEM 3. Voltage • Set the main switch to “ON”. • Start the engine. • Connect the pocket tester (DC 20 V) to the • Set the dimmer switch to “ ” or “ ”. headlight coupler (wire harness side), •...
  • Page 292 – ELEC LIGHTING SYSTEM EAS00789 EAS00790 2. The meter light fails to come on. 3. The tail/brake light fails to come on. 1. Meter light bulb and socket 1. Tail/brake light bulb and socket • Check the meter light bulb and socket for •...
  • Page 293 – ELEC LIGHTING SYSTEM EAS00791 4. The auxiliary light fails to come on. 1. Auxiliary light bulb and socket • Check the auxiliary light bulb and socket for continuity. Refer to “CHECKING THE BULBS AND BULB SOCKETS”. • Are the auxiliary light bulb and socket OK? Replace the auxiliary light bulb, socket or both.
  • Page 294: Signaling System

    – ELEC SIGNALING SYSTEM EAS00793 SIGNALING SYSTEM CIRCUIT DIAGRAM 7 - 32...
  • Page 295 – ELEC SIGNALING SYSTEM EAS00799 3. Voltage 3. The turn signal light, turn signal indicator light or both fail to blink. • Connect the pocket tester (DC 20 V) to the tail/brake light coupler (wire harness side) 1. Turn signal light bulb and socket as shown.
  • Page 296 – ELEC SIGNALING SYSTEM 4. Voltage 5. Voltage • Connect the pocket tester (DC 20 V) to the • Connect the pocket tester (DC 20 V) to the turn signal relay coupler as shown. turn signal relay coupler as shown. Positive tester probe →...
  • Page 297 – ELEC SIGNALING SYSTEM 6. Voltage • Set the main switch to “ON”. • Set the turn signal switch to “ ” or “ ”. • Connect the pocket tester (DC 20 V) to the • Measure the voltage (DC 12 V) of the turn signal light connector or turn signal chocolate 1 or dark green 2 at the turn indicator light connector (wire harness...
  • Page 298 – ELEC SIGNALING SYSTEM EAS00800 3. Voltage 4. The neutral indicator light fails to come on. • Connect the pocket tester (DC 20 V) to the 1. Neutral indicator light bulb and socket meter assembly coupler (wire harness • Check the neutral indicator light bulb and side) as shown.
  • Page 299 – ELEC SIGNALING SYSTEM EAS00804 2. Voltage 5. The fuel level gauge fails to operate. • Connect the pocket tester (DC 20 V) to the 1. Fuel sender meter assembly coupler (wire harness • Remove the fuel sender from the fuel tank. side) as shown.
  • Page 300 – ELEC SIGNALING SYSTEM 3. Fuel level gauge • Set the main switch to “ON”. • Move the float up È or down É. • Check that the fuel level gauge needle moves to “F” or “E”. È É NOTE: Before reading the fuel level gauge, leave the float in one position (either up or down) for at least three minutes.
  • Page 301: Carburetor Heating System

    – ELEC CARBURETOR HEATING SYSTEM EAS00820 CARBURETOR HEATING SYSTEM CIRCUIT DIAGRAM 7 - 42...
  • Page 302 – ELEC CARBURETOR HEATING SYSTEM EAS00821 EAS00739 TROUBLESHOOTING 2. Battery The carburetor heating system fails to • Check the condition of the battery. operate. Refer to “CHECKING AND CHARGING THE BATTERY” in chapter 3. Check: 1. fuse Minimum open-circuit voltage 2.
  • Page 303 – ELEC CARBURETOR HEATING SYSTEM EAS00823 4. Thermo switch • Remove the thermo switch from the wire harness. • Connect the pocket tester (Ω × 1) to the thermo switch 1 as shown. • Immerse the thermo switch in a container filled with water 2.
  • Page 304 – ELEC CARBURETOR HEATING SYSTEM EAS00824 EAS00826 5. Carburetor heater 6. Wiring • Remove the carburetor heater from the • Check the entire carburetor heating sys- carburetor. tem’s wiring. • Connect the pocket tester to the carbure- Refer to “CIRCUIT DIAGRAM”. tor heater as shown.
  • Page 305: Trbl Shtg

    TRBL SHTG CHAPTER 8 TROUBLESHOOTING STARTING FAILURES..................8-1 ENGINE..................... 8-1 FUEL SYSTEM..................8-1 ELECTRICAL SYSTEMS ................8-2 INCORRECT ENGINE IDLING SPEED............8-2 ENGINE..................... 8-2 FUEL SYSTEM..................8-2 ELECTRICAL SYSTEMS ................8-2 POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE .........8-3 ENGINE..................... 8-3 FUEL SYSTEM..................8-3 FAULTY GEAR SHIFTING................8-3 SHIFTING IS DIFFICULT ................8-3 SHIFT PEDAL DOES NOT MOVE ............
  • Page 306 TRBL SHTG FAULTY LIGHTING OR SIGNALING SYSTEM..........8-6 HEADLIGHT DOES NOT COME ON ............8-6 HEADLIGHT BULB BURNT OUT.............. 8-6 TAIL/BRAKE LIGHT DOES NOT COME ON ..........8-6 TAIL/BRAKE LIGHT BULB BURNT OUT..........8-6 TURN SIGNAL DOES NOT COME ON ............ 8-6 TURN SIGNALS FLASH SLOWLY ............8-6 TURN SIGNALS REMAIN LIT..............8-6 TURN SIGNALS FLASH QUICKLY............
  • Page 307: Troubleshooting

    TRBL STARTING FAILURES SHTG EAS00844 TROUBLESHOOTING NOTE: The following guide for troubleshooting does not cover all the possible causes of trouble. It should be helpful, however, as a guide to basic troubleshooting. Refer to the relative procedure in this man- ual for checks, adjustments, and replacement of parts.
  • Page 308: Electrical Systems

    STARTING FAILURES/ TRBL INCORRECT ENGINE IDLING SPEED SHTG ELECTRICAL SYSTEMS Battery Ignition system • Discharged battery • Faulty C.D.I unit • Faulty battery • Faulty pickup coil Fuse • Broken A.C. magneto rotor woodruff key • Blown, damaged or incorrect fuse Switches and wiring •...
  • Page 309: Poor Medium-And-High-Speed Performance

    POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE/ TRBL FAULTY GEAR SHIFTING/FAULTY CLUTCH SHTG EAS00849 POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE Refer to “STARTING FAILURES”. ENGINE FUEL SYSTEM Air filter Carburetor • Clogged air filter element • Faulty diaphragm Air intake system • Incorrect fuel level • Bent, clogged or disconnected carburetor •...
  • Page 310: Overheating

    OVERHEATING/POOR BRAKING PERFORMANCE/ TRBL FAULTY FRONT FORK LEGS SHTG EAS00854 OVERHEATING ENGINE CHASSIS Cylinder head and piston Brake(s) • Heavy carbon buildup • Dragging brake Engine oil ELECTRICAL SYSTEMS • Incorrect oil level Spark plug • Incorrect oil viscosity • Incorrect spark plug gap •...
  • Page 311: Unstable Handling

    TRBL UNSTABLE HANDLING SHTG EAS00862 UNSTABLE HANDLING Handlebar Rear shock absorber assembly(ies) • Bent or improperly installed handlebar • Faulty rear shock absorber spring Steering head components • Leaking oil • Improperly installed upper bracket Tire(s) • Improperly installed lower bracket •...
  • Page 312: Faulty Lighting Or Signaling System

    TRBL FAULTY LIGHTING OR SIGNALING SYSTEM SHTG EAS00866 FAULTY LIGHTING OR SIGNALING SYSTEM HEADLIGHT DOES NOT COME ON TURN SIGNAL DOES NOT COME ON • Wrong headlight bulb • Faulty turn signal switch • Too many electrical accessories • Faulty turn signal relay •...
  • Page 313 YBR125ED 2005 WIRING DIAGRAM 1 A.C. magneto COLOR CODE 2 Neutral switch B .... Black 3 Rectifier/regulator Br... Brown 4 Battery Ch..Chocolate 5 Fuse Dg..Dark green 6 Starter relay G ... Green 7 Starter motor L .... Blue 8 Main switch Sb ..
  • Page 314 YAMAHA MOTOR CO., LTD.
  • Page 316 YBR125ED 2005 YBR125ED 2005 SCHEMA ELETTRICO DIAGRAMA ELÉCTRICO DE LA YBR125ED 2005 SCHÉMA DE CÂBLAGE SCHALTPLAN YBR125ED 2005 YBR125ED 2005 WIRING DIAGRAM LOCK (BLACK) (RED) (RED) ( RED ) (BLACK) (BLACK) (BLUE) (BLUE) (BLACK) (BLACK) _ a b (GREEN)