Yamaha YFM250RX 2008 Service Manual
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Yamaha YFM250RX 2008 Service Manual

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2008
SERVICE MANUAL
YFM250RX
LIT-11616-21-22
4D3-28197-10

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Summary of Contents for Yamaha YFM250RX 2008

  • Page 1 2008 SERVICE MANUAL YFM250RX LIT-11616-21-22 4D3-28197-10...
  • Page 2 EBS00001 YFM250RX SERVICE MANUAL © 2007 by Yamaha Motor Corporation, U.S.A. First Edition, July 2007 All rights reserved. Any reproduction or unauthorized use without the written permission of Yamaha Motor Corporation, U.S.A. is expressly prohibited. Printed in U.S.A LIT-11616-21-22...
  • Page 3 EBS00002 NOTICE This manual was produced by the Yamaha Motor Company primarily for use by Yamaha dealers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one man- ual, so it is assumed that anyone who uses this book to perform maintenance and repairs on Yamaha machine has a basic understanding of the mechanical ideas and the procedures of machine repair.
  • Page 4 EBS00004 HOW TO USE THIS MANUAL MANUAL ORGANIZATION This manual consists of chapters for the main categories of subjects. (See “symbols”) 1st title : This is the title of the chapter with its symbol in the upper right corner of each page. 2nd title : This title indicates the section of the chapter and only appears on the first page of each section.

  • Page 5: Specifications

    EBS00006 SYMBOLS The following symbols are not relevant to every machine. INFO Symbols indicate the subject of each chapter. General information Specifications Periodic checks and adjustments Engine Carburetor Chassis Electrical CHAS Troubleshooting Symbols indicate the following Serviceable with engine mounted Filling fluid Lubricant Special tool...

  • Page 7: Table Of Contents

    EBS00008 TABLE OF CONTENTS GENERAL INFORMATION INFO SPECIFICATIONS SPEC PERIODIC CHECKS AND ADJUSTMENTS ENGINE CARBURETOR CARB CHASSIS CHAS ELECTRICAL ELEC TROUBLESHOOTING TRBL SHTG...
  • Page 8 CHAPTER 1 GENERAL INFORMATION MACHINE IDENTIFICATION ........1-1 VEHICLE IDENTIFICATION NUMBER.
  • Page 9 CHAPTER 3 PERIODIC CHECKS AND ADJUSTMENTS INTRODUCTION ......... . . 3-1 PERIODIC MAINTENANCE CHART FOR THE EMISSION CONTROL SYSTEM .

  • Page 10: Engine

    CHECKING AND LUBRICATING THE CABLES ....3-43 LUBRICATING THE LEVERS AND PEDALS ....3-44 ELECTRICAL SYSTEM .
  • Page 11 CHECKING THE CLUTCH PLATES ......4-44 CHECKING THE CLUTCH SPRINGS ......4-45 CHECKING THE CLUTCH HOUSING .

  • Page 12: Carburetor

    CHAPTER 5 CARBURETOR CARBURETOR ..........5-1 CHECKING THE CARBURETOR .

  • Page 13: Electrical

    ASSEMBLING THE REAR BRAKE CALIPER ....6-36 INSTALLING THE FRONT BRAKE CALIPERS ....6-38 INSTALLING THE REAR BRAKE CALIPER .

  • Page 14: Troubleshooting

    CHECKING THE BULBS AND BULB SOCKETS ....7-5 TYPES OF BULBS ........7-5 CHECKING THE CONDITION OF THE BULBS .
  • Page 15 CLUTCH SLIPPING/DRAGGING ......8-3 CLUTCH SLIPPING ........8-3 CLUTCH DRAGGING .

  • Page 16: Gen Info

    MACHINE IDENTIFICATION INFO EBS00009 GENERAL INFORMATION MACHINE IDENTIFICATION EBS00010 VEHICLE IDENTIFICATION NUMBER The vehicle identification number stamped into the left side of the frame. EBS00011 MODEL LABEL The model label is affixed to the air filter case cover. This information will be needed to order spare parts.

  • Page 17: Important Information

    5. Keep all parts away from any source of fire. EBS00014 REPLACEMENT PARTS 1. 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 18: Bearings And Oil Seals

    IMPORTANT INFORMATION INFO EBS00017 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manu- facturer’s marks or numbers are visible. When installing oil seals, lubricate the oil seal lips with a light coat of lithium-soap-based grease. Oil bearings liberally when installing, if appro- priate.

  • Page 19: Checking The Connections

    IMPORTANT INFORMATION INFO EBS00019 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 20: Special Tools

    SPECIAL TOOLS INFO EBS00021 SPECIAL TOOLS The following special tools are necessary for complete and accurate tune-up and assembly. Use only the appropriate special tools; this will help prevent damage caused by the use of inappropriate tools or improvised techniques. Special tools may differ by shape and part number from country to country.
  • Page 21 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Adapter (M10) Adapter #2 Adapter 90890-01383 YU-90062 This tool is used to install the crankshaft. Spacer 90890-01288 This tool is used to install the crankshaft. Piston pin puller set Piston pin puller YU-01304 90890-01304 YU-01304...
  • Page 22 SPECIAL TOOLS INFO Tool No. Tool name/Function Illustration Compression gauge Engine compression tester 90890-03081 YU-33223 This tool is needed to measure the engine compression. Extension 90890-04082 This tool is needed to measure engine com- pression. Pocket tester Analog pocket tester 90890-03112 YU-03112-C This instrument is needed for checking the...
  • Page 23 This instrument is necessary for checking the ignition system components. Digital tachometer 90890-06760 YU-39951-B This tool is needed for observing engine rpm. Yamaha bond No. 1215 ® (Three Bond No. 1215 90890-85505 This bond is used on crankcase mating sur- faces, etc.

  • Page 24: Spec

    SPEC GENERAL SPECIFICATIONS EBS01001 SPECIFICATIONS GENERAL SPECIFICATIONS Item Standard Model code 4D31 4D35 4D39 Dimensions Overall length 1,625 mm (64.0 in) Overall width 1,070 mm (42.1 in) Overall height 1,040 mm (40.9 in) Seat height 730 mm (28.7 in) Wheelbase 1,110 mm (43.7 in) Minimum ground clearance 100 mm (3.94 in)
  • Page 25 SPEC GENERAL SPECIFICATIONS Item Standard Fuel Type Unleaded gasoline only Fuel tank capacity 9.0 L (1.97 Imp gal, 2.37 US gal) Fuel reserve amount 1.0 L (0.22 Imp gal, 0.26 US gal) Carburetor BSR29 × 1 Type/quantity Manufacturer MIKUNI Spark plug Type/manufacturer DR7EA/NGK Spark plug gap...
  • Page 26 SPEC GENERAL SPECIFICATIONS Item Standard Brake Front brake type Dual disc brake operation Right hand operation Rear brake type Single disc brake operation Right foot operation Suspension Front suspension Double wishbone Rear suspension Swingarm Shock absorber Front shock absorber Coil spring/oil damper Rear shock absorber Coil spring/gas-oil damper Wheel travel...

  • Page 27: Engine Specifications

    SPEC ENGINE SPECIFICATIONS EBS01002 ENGINE SPECIFICATIONS Item Standard Limit Cylinder head Volume 20.50 ~ 21.50 cm (1.25 ~ 1.31 cu.in) • • • Warp limit • • • 0.05 mm (0.0020 in) Cylinder Bore size 74.000 ~ 74.016 mm (2.9134 ~ 2.9140 in) 74.100 mm (2.9173 in) Camshaft Drive method...
  • Page 28 SPEC ENGINE SPECIFICATIONS Item Standard Limit Valve, valve seat, valve guide Valve clearance (cold) 0.05 ~ 0.10 mm (0.0020 ~ 0.0039 in) • • • 0.10 ~ 0.15 mm (0.0039 ~ 0.0059 in) • • • Valve dimensions Head Diameter Face Width Seat Width Margin Thickness...
  • Page 29 SPEC ENGINE SPECIFICATIONS Item Standard Limit Valve spring Inner spring Free length 36.17 mm (1.42 in) 34.36 mm (1.35 in) 36.17 mm (1.42 in) 34.36 mm (1.35 in) Installed length (valve closed) 30.50 mm (1.20 in) • • • 30.50 mm (1.20 in) •...
  • Page 30 SPEC ENGINE SPECIFICATIONS Item Standard Limit Tilt limit • • • 2.5°/1.60 mm (2.5°/0.063 in) • • • 2.5°/1.60 mm (2.5°/0.063 in) Direction of winding (top view) Clockwise • • • Clockwise • • • Piston Piston to cylinder clearance 0.010 ~ 0.025 mm (0.0004 ~ 0.0010 in) 0.15 mm (0.006 in)
  • Page 31 SPEC ENGINE SPECIFICATIONS Item Standard Limit Piston rings Top ring Type Barrel • • • Dimensions (B × T) 0.90 × 2.75 mm (0.035 × 0.108 in) • • • End gap (installed) 0.19 ~ 0.31 mm (0.007 ~ 0.012 in) 0.56 mm (0.022 in) Side clearance...
  • Page 32 SPEC ENGINE SPECIFICATIONS Item Standard Limit Balancer Balancer drive method Gear • • • Clutch Friction plate 1 (inside dia.: 104.5 ~ 105.5 mm) Thickness 2.9 ~ 3.1 mm (0.114 ~ 0.122 in) 2.8 mm (0.110 in) Quantity • • • Friction plate 2 (inside dia.: 104.5 ~ 105.5 mm) Thickness...
  • Page 33 SPEC ENGINE SPECIFICATIONS Item Standard Limit Carburetor I. D. mark 4D31 00 • • • Main jet (M.J) #133.8 • • • Main air jet (M.A.J) #140 • • • Jet needle (J.N) 5DH66-1 • • • Needle jet (N.J) P-0M •...

  • Page 34: Chassis Specifications

    SPEC CHASSIS SPECIFICATIONS EBS01003 CHASSIS SPECIFICATIONS Item Standard Limit Front suspension Shock absorber travel 90.7 mm (3.57 in) • • • Spring free length 248.5 mm (9.78 in) • • • Spring rate 23.0 N/mm (2.34 kg/mm, 131.26 lb/in) • • • Spring stroke 0.0 ~ 90.7 mm (0.0 ~ 3.57 in) •...
  • Page 35 SPEC CHASSIS SPECIFICATIONS Item Standard Limit Front disc brake Type Dual • • • Disc outside diameter × thickness 161.0 × 3.5 mm (6.34 × 0.14 in) 3.0 mm (0.12 in) Brake disk maximum deflection 0.15 mm (0.006 in) Pad thickness inner 4.4 mm (0.17 in) 1.5 mm (0.06 in)

  • Page 36: Electrical Specifications

    • • • Advanced timing (B.T.D.C.) 24.4°/5,000 r/min Advancer type Digital type • • • CDI unit model/manufacturer 4D3/YAMAHA • • • 248 ~ 372 Ω at 20°C (68°F) red–white Pickup coil resistance/color • • • Ignition coil Model/manufacturer 2JN/YAMAHA •...
  • Page 37 SPEC ELECTRICAL SPECIFICATIONS Item Standard Limit Starter relay Model/manufacturer A4616-051/JIDECO • • • Amperage rating 180 A • • • 4.18 ~ 4.62 Ω Coil winding resistance • • • Headlight relay Headlight relay Model/manufacturer G8HN-1C4T-DJ-Y52/OMRON • • • 94.5 Ω ~ 115.5 Ω Coil resistance •...

  • Page 38: Tightening Torques

    SPEC TIGHTENING TORQUES EBS01005 TIGHTENING TORQUES ENGINE TIGHTENING TORQUES Tightening torque Part Thread Part to be tightened Q’ty Remarks name size m•kg ft•lb Cylinder head (upper) Bolt See NOTE *1 Cylinder head Bolt Camshaft lock plate Bolt Cylinder head side cover (1 and 2) Bolt Cylinder head side cover 3 Bolt...
  • Page 39 SPEC TIGHTENING TORQUES Tightening torque Part Thread Part to be tightened Q’ty Remarks name size m•kg ft•lb Clutch boss nut Use a lock washer. Clutch spring Screw Push lever adjusting screw locknut Push lever shaft Bolt Chain case cover Bolt Drive sprocket nut 11.0 Use a lock...

  • Page 40: Chassis Tightening Torques

    SPEC TIGHTENING TORQUES EBS01006 CHASSIS TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Remarks m•kg ft•lb Engine upper stay and frame Engine upper stay and engine Engine lower stay and engine Engine and frame Engine lower stay and frame Swingarm pivot shaft and frame Rear shock absorber and frame Rear shock absorber locknut...
  • Page 41 SPEC TIGHTENING TORQUES Tightening torque Part to be tightened Thread size Remarks m•kg ft•lb Front brake master cylinder and brake lever Throttle assembly and handlebar Front brake master cylinder and brake hose Brake hose joint and frame Bleed screw Front brake pad retaining bolt Front brake caliper and brake hose Rear brake caliper retaining bolt Parking brake case and caliper...

  • Page 42: How To Use The Conversion Table

    HOW TO USE THE CONVERSION TABLE/ SPEC GENERAL TIGHTENING TORQUE SPECIFICATIONS EBS00022 EBS00023 HOW TO USE THE CONVERSION GENERAL TIGHTENING TORQUE TABLE SPECIFICATIONS All specification data in this manual are listed This chart specifies tightening torques for in SI and METRIC UNITS. standard fasteners with a standard ISO thread Use this table to convert METRIC unit data to pitch.

  • Page 43: Lubrication Points And Lubricant Types

    SPEC LUBRICATION POINTS AND LUBRICANT TYPES EBS00024 LUBRICATION POINTS AND LUBRICANT TYPES ENGINE Lubrication point Lubricant Oil seal lips O-rings Bearings Cylinder head bolts (bearing surface of bolts) Cylinder head bolts (thread part) Cylinder body surface Crankshaft journals Connecting rod small end and big end Piston pin Piston surface Boss periphery...
  • Page 44 SPEC LUBRICATION POINTS AND LUBRICANT TYPES Lubrication point Lubricant Sealant ® (Three Bond No.1215 Crankcase mating surfaces Yamaha bond No.1215 Sealant ® (Three Bond No.1215 AC magneto lead grommet (AC magneto cover) Yamaha bond No.1215 2-21...

  • Page 45: Oil Flow Diagrams

    SPEC OIL FLOW DIAGRAMS EBS00026 OIL FLOW DIAGRAMS Camshaft Oil filter element Oil pump Oil strainer Oil filter Oil cooler Pin, Cylinder with hole head Oil pump Drive axle Main axle Crank Cam shaft shaft Oil strainer Oil pan 2-22...
  • Page 46 SPEC OIL FLOW DIAGRAMS Camshaft Drive axle Main axle Push lever shaft Oil pump assembly Oil strainer Crankshaft assembly Oil filter element 2-23...
  • Page 47 SPEC OIL FLOW DIAGRAMS Oil cooler Oil hose 1 Oil hose 2 2-24...

  • Page 48: Cable Routing

    SPEC CABLE ROUTING EBS00028 CABLE ROUTING Front brake hose Front brake light switch lead Throttle cable Plastic band Clutch cable Parking brake cable Clutch switch lead Handlebar switch lead 2-25...
  • Page 49 SPEC CABLE ROUTING Clamp the front brake light switch lead at the Clamp the clutch switch lead and handlebar switch bends of handlebar. lead at the bends of handlebar. Route the front brake hose and throttle cable through the guide of the handlebar protector. Route the throttle cable under the front brake hose.
  • Page 50 SPEC CABLE ROUTING Indicator light lead Carburetor warmer lead Neutral switch lead Main switch lead Air vent hose Rear brake reservoir cover Coupler joint Air filter case breather hose Front brake light switch lead Throttle cable Front brake hose 2 Front brake hose 1 Oil cooler hose 1, 2 Clutch cable...
  • Page 51 SPEC CABLE ROUTING To the front panel Route the battery negative lead behind the clutch To the front fender cable holder. To the handlebar Route the air vent hose through the bracket. To the right headlight Make sure that the white paint mark on the air filter Make sure to route the oil cooler hoses 1and 2 case breather hose through the guide wire.
  • Page 52 SPEC CABLE ROUTING Route the parking brake cable and the clutch cable Route the neutral switch lead and rear brake light under the cross pipe and right of the steering col- switch lead as shown in the illustration. umn as shown in the illustration. Route the rear brake light switch lead, neutral switch lead, air vent hose, carburetor overflow hose and parking brake cable through the bracket.
  • Page 53 SPEC CABLE ROUTING Rear brake reservoir Rear brake light switch Clip Rear brake reservoir hose Rear brake master cylinder Parking brake cable Rear brake hose Rear brake caliper 2-30...
  • Page 54 SPEC CABLE ROUTING Make sure that the end of the clip is facing down- Install the rear brake reservoir hose, making sure ward. to face the white paint mark outward. Set the rear brake reservoir hose with the position- Insert the rear brake reservoir hose until it contacts ing yellow paint mark pointing down.
  • Page 55 SPEC CABLE ROUTING Clutch switch lead Neutral switch lead Air filter case breather hose Handlebar switch lead Ignition coil spark plug lead Air filter joint Bolt Ignition coil Air filter case Main harness Drain hose Air vent hose Frame complete Clamp Damper plate Battery negative lead...
  • Page 56 SPEC CABLE ROUTING To the front fender Route the carburetor overflow hose as shown in Route the wire harness above the guide for the the illustration. damper plate. Fasten the clamp with the engine. Fix point for wire harness Route the leads on the upper inside of the cover. Clamp near the hook of the air filter.
  • Page 57 SPEC CABLE ROUTING Indicator light Rear brake reservoir Coupler joint Rear brake light switch lead Main switch lead Air vent hose Front brake light switch lead Battery negative lead Throttle cable Carburetor warmer lead Regulator Starter motor lead Flange bolt Clutch switch lead Headlight lead Handlebar switch lead...
  • Page 58 SPEC CABLE ROUTING Install the indicator light as shown in the illustra- To the handlebar tion. Route the air vent hose through the bracket. Place the coupler joint above the front fender. Route the battery negative lead behind the clutch Route the front brake light switch lead and throttle cable holder.
  • Page 59 SPEC CABLE ROUTING Route the cables and leads through the guide of the front fender. Route the leads behind the clutch and parking brake cable. 2-36...
  • Page 60 SPEC CABLE ROUTING CDI unit Damper Band CDI unit lead Battery Relay lead Starter relay lead Starter relay Taillight lead Battery negative lead AC magneto coupler Starter motor lead Headlight relay Neutral relay 2-37...
  • Page 61 SPEC CABLE ROUTING Route the starter relay lead under the starter After connecting the taillight lead and each electric motor lead. part, the length between the air filter and AC mag- Clamp the taillight lead. neto coupler should be 185 mm (7.28 in) on Do not clamp.

  • Page 62: Chk Adj

    However, keep in mind that if the ATV isn’t used for a long period of time, the month main- tenance intervals should be followed. • Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools, data and technical skills.

  • Page 63: General Maintenance And Lubrication Chart

    GENERAL MAINTENANCE AND LUBRICATION CHART GENERAL MAINTENANCE AND LUBRICATION CHART INITIAL EVERY month Whichever CHECK OR MAINTENANCE comes ITEM 1300 2500 2500 5000 first (mi) (200) (800) (1600) (1600) (3200) hours Every 20 ~ 40 hours (more often in wet or dusty Air filter element •...
  • Page 64 GENERAL MAINTENANCE AND LUBRICATION CHART NOTE: • The air filter needs more frequent service if you are riding in unusually wet or dusty areas. • Hydraulic brake service • Regularly check and, if necessary, correct the brake fluid level. • Every two years replace the internal components of the brake master cylinders and calipers, and change the brake fluid.

  • Page 65: Seat, Fenders And Fuel Tank

    SEAT, FENDERS AND FUEL TANK EBS00033 SEAT, FENDERS AND FUEL TANK SEAT, FRONT FENDER AND HEADLIGHTS 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) Order Job/Part Q’ty...

  • Page 66: Foot Protectors And Engine Skid Plate

    SEAT, FENDERS AND FUEL TANK EBS00034 FOOT PROTECTORS AND ENGINE SKID PLATE 17 Nm (1.7 m•kg, 13 ft•Ib) 17 Nm (1.7 m•kg, 13 ft•Ib) 17 Nm (1.7 m•kg, 13 ft•Ib) 17 Nm (1.7 m•kg, 13 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) Order Job/Part Q’ty...

  • Page 67: Rear Fender And Air Fillter Case

    SEAT, FENDERS AND FUEL TANK REAR FENDER AND AIR FILLTER CASE 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) Order Job/Part Q’ty Remarks Removing the rear fender and air Remove the parts in the order listed.
  • Page 68 SEAT, FENDERS AND FUEL TANK 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) 7 Nm (0.7 m•kg, 5.2 ft•Ib) Order Job/Part Q’ty Remarks Air filter case For installation, reverse the removal procedure.

  • Page 69: Fuel Tank

    SEAT, FENDERS AND FUEL TANK EBS00042 FUEL TANK 7 Nm (0.7 m•kg, 5.2 ft•Ib) Order Job/Part Q’ty Remarks Removing the fuel tank Remove the parts in the order listed. Seat/front fender Refer to “SEAT, FENDERS AND FUEL TANK”. Fuel hose (fuel cock side) NOTE: NOTE: Before disconnecting the fuel hose, turn...

  • Page 70: Engine

    ADJUSTING THE VALVE CLEARANCE EAS00048 ENGINE ADJUSTING THE VALVE CLEARANCE The following procedure applies to all of the valves. NOTE: 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 the Top Dead Center (TDC) on the compression stroke.
  • Page 71 ADJUSTING THE VALVE CLEARANCE a. Turn the crankshaft counterclockwise. b. When the piston is at the Top Dead Center (TDC) on the compression stroke, align the “I” mark on the AC magneto rotor with the stationary pointer on the crankcase cover.

  • Page 72: Adjusting The Engine Idling Speed

    ADJUSTING THE VALVE CLEARANCE/ ADJUSTING THE ENGINE IDLING SPEED d. Measure the valve clearance again. e. If the valve clearance is still out of specifica- tion, repeat all of the valve clearance adjustment steps until the specified clear- ance is obtained. 6.

  • Page 73: Adjusting The Throttle Lever Free Play

    ADJUSTING THE ENGINE IDLING SPEED/ ADJUSTING THE THROTTLE LEVER FREE PLAY 4. Adjust: • engine idling speed a. Turn the throttle stop screw in direction until the specified idling speed is obtained. Idling speed becomes Direction higher. Idling speed becomes Direction lower.

  • Page 74: Adjusting The Speed Limiter

    ADJUSTING THE THROTTLE LEVER FREE PLAY/ ADJUSTING THE SPEED LIMITER 2. Adjust: • throttle lever free play First step: a. Slide back the rubber cover b. Loosen the locknut on the carburetor side. c. Turn the adjusting nut in direction until the correct free play is obtained.
  • Page 75 ADJUSTING THE SPEED LIMITER 1. Measure: • Speed limiter length Out of specification → Adjust. Speed limiter length Less than 12 mm (0.47 in) 2. Adjust: • speed limiter length a. Loosen the locknut b. Turn the adjusting screw in or out until the specified speed limiter length is obtained.

  • Page 76: Checking The Spark Plug

    CHECKING THE SPARK PLUG EBS00057 CHECKING THE SPARK PLUG 1. Disconnect: • spark plug cap 2. Remove: • spark plug 3. Check: • spark plug type Incorrect → Change. Standard spark plug NGK/DR7EA 4. Check: • electrode Wear/damage → Replace. •...

  • Page 77: Checking The Ignition Timing

    CHECKING THE IGNITION TIMING EBS00058 CHECKING THE IGNITION TIMING NOTE: NOTE: Engine idling speed and throttle cable free play should be adjusted properly before checking the ignition timing. 1. Attach: • digital tachometer Digital tachometer 90890-06760, YU-39951-B • timing light (onto the ignition coil spark plug lead) Timing light 90890-03141...

  • Page 78: Measuring The Compression Pressure

    MEASURING THE COMPRESSION PRESSURE MEASURING THE COMPRESSION PRESSURE The following procedure applies to the cylinder. NOTE: NOTE: Insufficient compression pressure will result in a loss of performance. 1. Measure: • Valve clearance Out of specification → Adjust. Refer to “ADJUSTING THE VALVE CLEAR- ANCE”...
  • Page 79 MEASURING THE COMPRESSION PRESSURE 6. Measure: • Compression pressure Out of specification → Refer to steps (c) and (d). Compression pressure (standard) 1,100 kPa/720 r/min (11.2 kgf/cm , 160 psi/720 r/min) Compression pressure (maximum) 1,300 kPa/720 r/min (13.3 kgf/cm , 189 psi /720 r/min) Compression pressure (minimum) 900 kPa/720 r/min (9.2 kgf/cm...

  • Page 80: Checking The Engine Oil Level

    MEASURING THE COMPRESSION PRESSURE/ CHECKING THE ENGINE OIL LEVEL 7. Install: • Spark plug Spark plug 18 Nm (1.8 m•kg, 13 ft•lb) 8. Connect: • Spark plug cap EBS01101 CHECKING THE ENGINE OIL LEVEL 1. Place the machine on a level surface. 2.

  • Page 81: Changing The Engine Oil

    CHECKING THE ENGINE OIL LEVEL/ CHANGING THE ENGINE OIL 4. Start the engine, warm it up for several min- utes, and then turn it off. 5. Check: • engine oil level NOTE: NOTE: Before checking the engine oil level, wait a few minutes until the oil has settled.
  • Page 82 CHANGING THE ENGINE OIL 8. Install: • engine oil drain bolt gasket • engine oil drain bolt Engine oil drain bolt 20 Nm (2.0 m•kg, 15 ft•lb) • oil filter element drain bolt Oil filter element drain bolt 10 Nm (1.0 m•kg, 7.4 ft•lb) 9.

  • Page 83: Adjusting The Clutch Cable

    CHANGING THE ENGINE OIL/ ADJUSTING THE CLUTCH CABLE 14.Check: • engine oil pressure a. Slightly loosen the oil gallery bolt b. Start the engine and keep it idling until engine oil starts to seep from the oil gallery bolt. If no engine oil comes out after one minute, turn the engine off so that it will not seize.

  • Page 84: Cleaning The Air Filter Element

    ADJUSTING THE CLUTCH CABLE/ CLEANING THE AIR FILTER ELEMENT EBS00073 CLEANING THE AIR FILTER ELEMENT NOTE: NOTE: There is a check hose at the bottom of the air filter case. If dust and/or water collects in this hose, clean the air filter element and air fil- ter case.
  • Page 85 CAUTION: Do not twist or wring out the element. This could damage the foam material. c. Apply Yamaha foam air filter oil or other quality foam air filter oil (not spray type). d. Squeeze out the excess oil. NOTE: NOTE: The element should be wet but not dripping.

  • Page 86: Cleaning The Spark Arrester

    CLEANING THE AIR FILTER ELEMENT/ CLEANING THE SPARK ARRESTER CLEANING THE SPARK ARRESTER 1. Clean: • Spark arrester WARNING • Select a well-ventilated area free of com- bustible materials. • Always let the exhaust system cool before performing this operation. •...

  • Page 87: Chassis

    ADJUSTING THE FRONT BRAKE/ADJUSTING THE BRAKE LEVER/ADJUSTING THE REAR BRAKE EBS00080 CHASSIS ADJUSTING THE FRONT BRAKE 1. Measure: • brake lever free play Out of specification → Bleed the front brake system. Refer to “BLEEDING THE HYDRAULIC BRAKE SYSTEM”. Brake lever free play (at the end of the brake lever) 0 mm (0 in) ADJUSTING THE BRAKE LEVER...

  • Page 88: Adjusting The Parking Brake

    ADJUSTING THE REAR BRAKE/ ADJUSTING THE PARKING BRAKE 2. Adjust: • rear brake pedal height a. Loosen the locknut b. Turn the adjusting bolt until the brake pedal height is within the specified limits. c. Tighten the locknut. NOTE: NOTE: When adjusting the brake pedal height make sure the locknut-to-adjusting bolt clearance does not exceed 2.2 ~ 3.2 mm (0.09 ~ 0.13 in).

  • Page 89: Checking The Brake Fluid Level

    ADJUSTING THE PARKING BRAKE/ CHECKING THE BRAKE FLUID LEVEL 2. Adjust: • parking brake cable end length a. Loosen the locknut and adjusting bolt b. Slide back the rubber cover c. Loosen the locknut d. Turn the adjusting nut in direction until the specified brake cable end length is obtained.

  • Page 90: Checking The Front Brake Pads

    CHECKING THE BRAKE FLUID LEVEL/ CHECKING THE FRONT BRAKE PADS 2. Check: • brake fluid level → Add Below the minimum level mark the recommended brake fluid to the proper level. Recommended brake fluid DOT 4 Front brake Rear brake WARNING •...

  • Page 91: Checking The Rear Brake Pads

    CHECKING THE FRONT BRAKE PADS/ CHECKING THE REAR BRAKE PADS 2. Check: • brake pads Wear indicator groove almost disappeared → Replace the brake pads as a set. Refer to “FRONT AND REAR BRAKES” in chapter 6. Brake pad wear limit 1.5 mm (0.06 in) 3.

  • Page 92: Adjusting The Rear Brake Light Switch

    ADJUSTING THE REAR BRAKE LIGHT SWITCH/ CHECKING THE BRAKE HOSES ADJUSTING THE REAR BRAKE LIGHT SWITCH NOTE: NOTE: • The rear brake light switch is operated by movement of the brake pedal. • The rear brake light switch is properly adjusted when the brake light comes on just before the braking effect starts.

  • Page 93: Bleeding The Hydraulic Brake System

    CHECKING THE BRAKE HOSES/ BLEEDING THE HYDRAULIC BRAKE SYSTEM 2. Check: • front brake hoses • front brake pipe • rear brake hose Cracks/wear/damage → Replace. 3. Check: • brake hose clamps Loosen → Tighten. 4. Hold the machine in an upright position and apply the front or rear brake.
  • Page 94 BLEEDING THE HYDRAULIC BRAKE SYSTEM NOTE: NOTE: • Be careful not to spill any brake fluid or allow the brake master cylinder reservoir or brake fluid reservoir to overflow. • When bleeding the hydraulic brake system, make sure there is always enough brake fluid before applying the brake.

  • Page 95: Adjusting The Shift Pedal

    BLEEDING THE HYDRAULIC BRAKE SYSTEM/ ADJUSTING THE SHIFT PEDAL j. Tighten the bleed screw to specification. 5 Nm (0.5 m•kg, 3.7 ft•lb) k. Fill the brake fluid reservoir to the proper level with the recommended brake fluid. Refer to “CHECKING THE BRAKE FLUID LEVEL”.

  • Page 96: Adjusting The Drive Chain Slack

    ADJUSTING THE DRIVE CHAIN SLACK ADJUSTING THE DRIVE CHAIN SLACK NOTE: NOTE: • Measure the drive chain slack halfway between the drive axle and the rear axle. • When checking and adjusting the drive chain slack, there should be no weight on the vehi- cle and all tires must be touching the ground.

  • Page 97: Checking The Steering System

    ADJUSTING THE DRIVE CHAIN SLACK/ CHECKING THE STEERING SYSTEM CAUTION: Excessive chain slack will overload the engine and other vital parts; keep the slack within the specified limits. e. If the chain slack cannot be adjusted, replace the sprockets and drive chain as a set.

  • Page 98: Adjusting The Toe-In

    ADJUSTING THE TOE-IN EBS00108 ADJUSTING THE TOE-IN 1. Place the machine on a level surface. 2. Measure: • toe-in Out of specification → Adjust. Toe-in 9 ~ 19 mm (0.35 ~ 0.75 in) NOTE: NOTE: Before measuring the toe-in, make sure that the tire pressure is correct.

  • Page 99: Checking The Front And Rear Shock Absorbers

    ADJUSTING THE TOE-IN/CHECKING THE FRONT AND REAR SHOCK ABSORBERS a. Mark both tie-rods ends. This reference point will be needed during adjustment. b. Loosen the locknuts (tie-rod end) of both tie-rods. c. The same number of turns should be given to both the right and left tie-rods until the specified toe-in is obtained.

  • Page 100: Adjusting The Front Shock Absorbers

    ADJUSTING THE FRONT SHOCK ABSORBERS EBS00111 ADJUSTING THE FRONT SHOCK ABSORBERS WARNING Always adjust the spring preload of both front shock absorbers to the same setting. Uneven adjustment can result in poor han- dling and loss of stability. 1. Adjust: •...

  • Page 101: Adjusting The Rear Shock Absorber

    ADJUSTING THE REAR SHOCK ABSORBER EBS00111 ADJUSTING THE REAR SHOCK ABSORBER 1. Adjust: • spring preload a. Elevate the rear wheels by placing a suit- able stand under the frame. b. Loosen the locknut c. Turn the adjusting nut in direction Spring preload is Direction increased (suspension is...

  • Page 102: Checking The Tires

    • TIRE CHARACTERISTICS 1) Tire characteristics influence the han- dling of ATVs. The tires listed below have been approved by Yamaha Motor Co., Ltd. for this model. If other tire com- binations are used, they can adversely affect your machine’s handling charac- teristics and are therefore not recom- mended.
  • Page 103 CHECKING THE TIRES 1. Measure: • tire pressure Out of specification → Adjust. NOTE: NOTE: • The low-pressure tire gauge is included as standard equipment. • If dust or the like is stuck to this gauge, it will not provide the correct readings. Therefore, take two measurements of the tire’s pressure and use the second reading.

  • Page 104: Checking The Wheels

    2. Check: • cable operation → Unsmooth operation Lubricate replace. Recommended lubricant Yamaha chain and cable lube or engine oil NOTE: NOTE: Hold the cable end up and apply several drops of lubricant to the cable. 3. Apply: • Lithium-soap-based grease...

  • Page 105: Lubricating The Levers And Pedals

    LUBRICATING THE LEVERS AND PEDALS EBS00118 LUBRICATING THE LEVERS AND PEDALS Lubricate the pivoting point and metal-to-metal moving parts of the levers and pedal. Recommended lubricants Brake lever Silicone grease Clutch lever and brake pedal Lithium-soap-based grease 3-44...

  • Page 106: Electrical System

    CHECKING AND CHARGING THE BATTERY EBS00120 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 107 CHECKING AND CHARGING THE BATTERY NOTE: NOTE: Since MF batteries are sealed, it is not possi- ble to check the charge state of the battery by measuring the specific gravity of the electro- lyte. Therefore, the charge of the battery has to be checked by measuring the voltage at the battery terminals.
  • Page 108 CHECKING AND CHARGING THE BATTERY Example c. Open-circuit voltage = 12.0 V d. Charging time = 6.5 hours e. Charge of the battery = 20 ~ 30% 5. Charge: Charging Ambient temperature 20°C (68°F) • battery (refer to the appropriate charging method illustration) WARNING Do not quick charge a battery.
  • Page 109 CHECKING AND CHARGING THE BATTERY • As shown in the following illustration, the open-circuit voltage of an MF battery sta- bilizes about 30 minutes after charging has been completed. Therefore, wait 30 minutes after charging is completed before measuring the open-circuit voltage. 3-48...
  • Page 110 CHECKING AND CHARGING THE BATTERY Charging method using a variable-current (voltage) charger Charger Ammeter Measure the open-circuit Leave the battery unused for voltage prior to charging. more than 30 minutes before measuring its open-circuit voltage. Connect a charger and ammeter to the battery Set the charging voltage to 16 ~ 17 V.
  • Page 111 CHECKING AND CHARGING THE BATTERY Charging method using a constant voltage charger Measure the open-circuit Leave the battery unused for more voltage prior to charging. than 30 minutes before measuring its open-circuit voltage. Connect a charger and ammeter to the battery and start charging.
  • Page 112 CHECKING AND CHARGING THE BATTERY 6. Install: • battery 7. Connect: • battery leads (to the battery terminals) CAUTION: First, connect the positive battery lead and then the negative battery lead 8. Check: • battery terminals Dirt → Clean with a wire brush. Loose connection →...

  • Page 113: Checking The Fuses

    CHECKING THE FUSES EBS00121 CHECKING THE FUSES The following procedure applies to all of the fuses. CAUTION: To avoid a short circuit, always set the main switch to “OFF” when checking or replac- ing a fuse. 1. Remove: • seat •...

  • Page 114: Adjusting The Headlight Beam

    CHECKING THE FUSES/ ADJUSTING THE HEADLIGHT BEAM Amperage Items Q’ty rating Main 15 A Reserve 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 ignition systems to malfunction and could...

  • Page 115: Replacing A Headlight Bulb

    REPLACING A HEADLIGHT BULB EBS00124 REPLACING A HEADLIGHT BULB 1. Remove: • headlight Refer to “SEAT, FENDERS AND FUEL TANK”. 2. Disconnect: • headlight lead coupler 3. Remove: • headlight bulb holder cover 4. Remove: • bulb holder • bulb NOTE: NOTE: Push the headlight bulb holder inward, turn it...
  • Page 116 REPLACING A HEADLIGHT BULB 6. Install: • bulb holder • headlight bulb holder cover NOTE: NOTE: After installing the bulb holder cover, make sure that the “TOP” mark is in the position shown. 7. Connect: • headlight lead coupler 8. Install: •...

  • Page 117: Eng

    ENGINE REMOVAL ENGINE ENGINE REMOVAL MUFFLER AND EXHAUST PIPE 34 Nm (3.4 m•kg, 25 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) 8 Nm (0.8 m•kg, 5.9 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the muffler and exhaust Remove the parts in the order listed.

  • Page 118: Installing The Exhaust Pipe And Muffler

    ENGINE REMOVAL INSTALLING THE EXHAUST PIPE AND MUFFLER 1. Install: • gasket (to muffler) Installed depth of gasket 3.5 mm (0.14 in) 2. Install: • exhaust pipe protector 3. Tighten: • exhaust pipe protector screws Screw 8 Nm (0.8 m•kg, 5.9 ft•lb) ®...

  • Page 119: Leads, Cables And Hoses

    ENGINE REMOVAL LEADS, CABLES AND HOSES 10 Nm (1.0 m•kg, 7.4 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the leads, cables and Remove the parts in the order listed. hoses Engine oil Drain. Oil cooler hose 1, 2 Refer to “CLUTCH”. Carburetor Refer to “CARBURETOR”...
  • Page 120 ENGINE REMOVAL 10 Nm (1.0 m•kg, 7.4 ft•lb) Order Job/Parts to remove Q’ty Remarks Neutral switch connector Disconnect. For installation, reverse the removal procedure.

  • Page 121: Engine Mounting Bolts

    ENGINE REMOVAL ENGINE MOUNTING BOLTS 33 Nm (3.3 m•kg, 24 ft•lb) 40 Nm (4.0 m•kg, 30 ft•lb) 66 Nm (6.6 m•kg, 49 ft•lb) 33 Nm (3.3 m•kg, 24 ft•lb) 66 Nm (6.6 m•kg, 49 ft•lb) 40 Nm (4.0 m•kg, 30 ft•lb) 33 Nm (3.3 m•kg, 24 ft•lb) Order Job/Parts to remove...

  • Page 122: Installing The Engine

    ENGINE REMOVAL INSTALLING THE ENGINE 1. Install: • Engine mounting bolt (rear lower side) • Engine mounting bolt (rear upper side) • Engine bracket bolts (upper side) • Engine mounting bolt (upper side) • Engine brackets (front side) • Engine mounting bolt (front side) NOTE: NOTE: •...

  • Page 123: Cylinder Head

    CYLINDER HEAD CYLINDER HEAD 10 Nm (1.0 m•kg, 7.4 ft•lb) 60 Nm (6.0 m•kg, 44 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 24 Nm (2.4 m•kg, 18 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) Order...
  • Page 124 CYLINDER HEAD 10 Nm (1.0 m•kg, 7.4 ft•lb) 60 Nm (6.0 m•kg, 44 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 24 Nm (2.4 m•kg, 18 ft•lb) 18 Nm (1.8 m•kg, 13 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) Order Job/Parts to remove...

  • Page 125: Removing The Cylinder Head

    CYLINDER HEAD REMOVING THE CYLINDER HEAD 1. Align: • “I” mark on the Pickup coil rotor (with the stationary pointer on the crank- case cover) a. Turn the Pickup coil rotor counterclockwise. b. When the piston is at TDC on the compres- sion stroke, align the “I”...

  • Page 126: Checking The Cylinder Head

    CYLINDER HEAD 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 127: Checking The Timing Chain Guides

    CYLINDER HEAD CHECKING THE TIMING CHAIN GUIDES The following procedure applies to the cam- shaft sprockets and timing chain guides. 1. Check: • Timing chain Damage/stiffness → Replace the timing chain and camshaft sprocket and crank- shaft sprocket as a set. 2.

  • Page 128: Installing The Cylinder Head

    CYLINDER HEAD b. Remove the screwdriver and slowly release the timing chain tensioner rod. c. Make sure that the timing chain tensioner rod comes out of the timing chain tensioner housing smoothly. If there is rough move- ment, replace the timing chain tensioner. 3.
  • Page 129 CYLINDER HEAD a. Turn the Pickup coil rotor counterclockwise. b. Align the “I” mark on the Pickup coil rotor with the stationary pointer on the crank- case cover. c. Remove the wire from the timing chain. d. Install the timing chain onto the camshaft sprocket, and then install the camshaft sprocket onto the camshaft.
  • Page 130 CYLINDER HEAD 6. Turn: • Crankshaft (several turns counterclockwise) 7. Check: • “I” mark Align the “I” mark on the pickup coil rotor with the stationary pointer on the crank- case cover. • “I” mark Align the “I” mark on the camshaft sprocket with the stationary pointer on the cylin- der head.

  • Page 131: Rocker Arm, Camshaft

    ROCKER ARM, CAMSHAFT ROCKER ARM, CAMSHAFT Order Job/Parts to remove Q’ty Remarks Removing the rocker arms and cam- Remove the parts in the order listed. shaft Cylinder head Refer to “CYLINDER HEAD”. Lock plate Locknut/valve clearance adjusting screw Camshaft Intake rocker arm shaft Intake rocker arm Exhaust rocker arm shaft Exhaust rocker arm...

  • Page 132: Removing The Rocker Arms And Camshaft

    ROCKER ARM, CAMSHAFT REMOVING THE ROCKER ARMS AND CAMSHAFT 1. Loosen: • Locknut • Valve clearance adjusting screw 2. Remove: • Stopper plate 3. Remove: • Camshaft • Bearing NOTE: NOTE: Screw 10 mm (0.396 in) bolt into the threaded end of the camshaft and then pull out the camshaft.

  • Page 133: Checking The Camshaft

    ROCKER ARM, CAMSHAFT CHECKING THE CAMSHAFT 1. Check: • Bearing Damage/wear → Replace. 2. Check: • Camshaft lobes → Blue discoloration/pitting/scratches Replace the camshaft. 3. Measure: • Camshaft lobe dimensions Out of specification → Replace the cam- shaft. Camshaft lobe dimension Intake A 36.890 ~ 36.990 mm (1.4524 ~ 1.4563 in)

  • Page 134: Checking The Rocker Arms And Rocker Arm

    ROCKER ARM, CAMSHAFT CHECKING THE ROCKER ARMS AND ROCKER ARM SHAFTS The following procedure applies to all of the rocker arms and rocker arm shafts. 1. Check: • Rocker arms • Valve clearance adjusting screws Damage/wear → Replace. 2. Check: •...

  • Page 135: Installing The Camshaft And Rocker Arms

    ROCKER ARM, CAMSHAFT INSTALLING THE CAMSHAFT AND ROCKER ARMS 1. Lubricate: • Camshaft Recommended lubricant Camshaft Molybdenum disulfide oil Camshaft bearing Engine oil 2. Lubricate: • Rocker arm • Rocker arm shaft Recommended lubricant Rocker arm Molybdenum disulfide oil Rocker arm shaft Engine oil 3.
  • Page 136 ROCKER ARM, CAMSHAFT 5. Install: • Camshaft NOTE: NOTE: Screw a 10 mm bolt into the threaded end of the camshaft and then install the camshaft. 6. Install: • Lock plate 7. Tighten: • Lock plate bolts Lock plate bolt 8 Nm (0.8 m•kg, 5.9 ft•lb) ®...

  • Page 137: Valves And Valve Springs

    VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS Order Job/Parts to remove Q’ty Remarks Removing the valves and valve Remove the parts in the order listed. springs Cylinder head Refer to “CYLINDER HEAD”. Rocker arm Refer to “ROCKER ARM, CAMSHAFT”. Camshaft Valve cotter Valve spring retainer...

  • Page 138: Removing The Valves

    VALVES AND VALVE SPRINGS REMOVING THE VALVES The following procedure applies to all of the valves and related components. NOTE: 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 139: Checking The Valves And Valve Guides

    VALVES AND VALVE SPRINGS 3. Remove: • Upper spring seat • Inner valve spring • Outer valve spring • Valve • Lower spring seat • Valve stem seal NOTE: NOTE: Identify the position of each part very carefully so that it can be reinstalled in its original place. CHECKING THE VALVES AND VALVE GUIDES The following procedure applies to all of the...
  • Page 140 VALVES AND VALVE SPRINGS 2. Replace: • Valve guide NOTE: NOTE: To ease valve guide removal and installation, and to maintain the correct fit, heat the cylinder head to 100°C (212°F) in an oven. a. Remove the valve guide with the valve guide remover b.

  • Page 141: Checking The Valve Seats

    VALVES AND VALVE SPRINGS 5. Measure: • Valve margin thickness D Out of specification → Replace the valve. Valve margin thickness Valve margin thickness D (intake) 0.80 ~ 1.20 mm (0.0315 ~ 0.0472 in) Valve margin thickness D (exhaust) 0.80 ~ 1.20 mm (0.0315 ~ 0.0472 in) 6.
  • Page 142 VALVES AND VALVE SPRINGS 3. Measure: • Valve seat width Out of specification → Replace the cylinder head. Valve seat width Valve seat width C (intake) 0.90 ~ 1.10 mm (0.0354 ~ 0.0433 in) Valve seat width C (exhaust) 0.90 ~ 1.10 mm (0.0354 ~ 0.0433 in) a.
  • Page 143 VALVES AND VALVE SPRINGS a. Apply a coarse lapping compound to the valve face. CAUTION: Do not let the lapping compound enter the gap between the valve stem and the valve guide. b. Apply molybdenum disulfide oil onto the valve stem. c.

  • Page 144: Checking The Valve Springs

    VALVES AND VALVE SPRINGS CHECKING THE VALVE SPRINGS The following procedure applies to all of the valve springs. 1. Measure: • Valve spring free length Out of specification → Replace the valve spring. Inner spring Free length (intake) 36.17 mm (1.42 in) Free length (exhaust) 36.17 mm (1.42 in) Outer spring...

  • Page 145: Installing The Valves

    VALVES AND VALVE SPRINGS 3. Measure: • Valve spring tilt Out of specification → Replace the valve spring. Inner spring Spring tilt (intake) 2.5°/1.60 mm (2.5°/0.063 in) Spring tilt (exhaust) 2.5°/1.60 mm (2.5°/0.063 in) Outer spring Spring tilt (intake) 2.5°/1.60 mm (2.5°/0.063 in) Spring tilt (exhaust) 2.5°/1.60 mm (2.5°/0.063 in) INSTALLING THE VALVES...
  • Page 146 VALVES AND VALVE SPRINGS 4. Install: • Valve cotters NOTE: NOTE: Install the valve cotters by compressing the valve spring with the valve spring compressor and the valve spring compressor attachment Valve spring compressor 90890-04019, YM-04019 Valve spring compressor attachment 90890-01243 Valve spring compressor adapter (26 mm)

  • Page 147: Cylinder And Piston

    CYLINDER AND PISTON CYLINDER AND PISTON 10 Nm (1.0 m•kg, 7.4 ft•lb) 17 Nm (1.7 m•kg, 13 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the cylinder and piston Remove the parts in the order listed. Cylinder head Refer to “CYLINDER HEAD”. Oil delivery pipe Cylinder Dowel pin...

  • Page 148: Removing The Piston

    CYLINDER AND PISTON REMOVING THE PISTON 1. Remove: • Piston pin clips • Piston pin • Piston NOTE: 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 149 CYLINDER AND PISTON a. Measure cylinder bore “C” with the cylinder bore gauge. NOTE: NOTE: Measure cylinder bore “C” by taking side-to- side and front-to-back measurements of the cylinder. Then, find the average of the mea- surements. Bore “C” 74.000 ~ 74.016 mm (2.9134 ~ 2.9140 in) Wear limit 74.100 mm (2.9173 in)

  • Page 150: Checking The Piston Rings

    CYLINDER AND PISTON Piston-to-cylinder clearance 0.010 ~ 0.025 mm (0.0004 ~ 0.0010 in) Limit 0.15 mm (0.006 in) f. If out of specification, rebore or replace the cylinder, and replace the piston and piston rings as a set. CHECKING THE PISTON RINGS 1.
  • Page 151 CYLINDER AND PISTON 2. Install: • Piston ring (into the cylinder) NOTE: NOTE: Level the piston ring into the cylinder with the piston crown. 40 mm (1.476 in) 3. Measure: • Piston ring end gap Out of specification → Replace the piston ring.

  • Page 152: Checking The Piston Pin

    CYLINDER AND PISTON 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 Out of specification → Replace the piston pin. Piston pin outside diameter 16.991 ~ 17.000 mm (0.6689 ~ 0.6693 in)

  • Page 153: Installing The Piston And Cylinder

    CYLINDER AND PISTON INSTALLING THE PISTON AND CYLINDER 1. Install: • Lower oil ring rail • Oil ring expander • Upper oil ring rail • 2nd ring • Top ring NOTE: NOTE: Be sure to install the piston rings so that the “T”...
  • Page 154 CYLINDER AND PISTON 5. Offset: • Piston ring end gaps Top ring Upper oil ring rail Oil ring expander Lower oil ring rail 2nd ring 20 mm 6. Install: • Cylinder NOTE: NOTE: • While compressing the piston rings with one hand, install the cylinder with the other hand.

  • Page 155: Clutch

    CLUTCH CLUTCH 73 Nm (7.3 m•kg, 54 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the clutch cover Remove the parts in the order listed. Engine oil Drain.
  • Page 156 CLUTCH 8 Nm (0.8 m•kg, 5.9 ft•lb) 75 Nm (7.5 m•kg, 55 ft•lb) 80 Nm (8.0 m•kg, 59 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the clutch Remove the parts in the order listed. Clutch spring Pressure plate Primary drive gear nut Friction plate Clutch plate Clutch boss nut...
  • Page 157 CLUTCH 8 Nm (0.8 m•kg, 5.9 ft•lb) 75 Nm (7.5 m•kg, 55 ft•lb) 80 Nm (8.0 m•kg, 59 ft•lb) Order Job/Parts to remove Q’ty Remarks Push rod 2/Ball For installation, reverse the removal procedure. 4-41...
  • Page 158 CLUTCH Order Job/Parts to remove Q’ty Remarks Removing the push lever shaft Remove the parts in the order listed. Shift pedal Refer to “SHIFT SHAFT”. Left crankcase cover Refer to “PICK UP COIL ROTOR AND STARTER CLUTCH”. Clutch assembly Clutch cable Bolt Push lever shaft Torsion spring...

  • Page 159: Removing The Clutch

    CLUTCH REMOVING THE CLUTCH 1. Remove: • Bolt • Clutch spring NOTE: NOTE: Loosen the bolts in stages and in a crisscross pattern. 2. Straighten the lock washer tab. 3. Loosen: • Primary drive gear nut • Clutch boss nut NOTE: NOTE: •...

  • Page 160: Checking The Friction Plates

    CLUTCH CHECKING THE FRICTION PLATES The following procedure applies to all of the friction plates. 1. Check: • Friction plate Damage/wear → Replace the friction plate. 2. Measure: • Friction plate thickness Out of specification → Replace the friction plate. NOTE: NOTE: Measure the friction plate at four places.

  • Page 161: Checking The Clutch Springs

    CLUTCH CHECKING THE CLUTCH SPRINGS The following procedure applies to all of the clutch springs. 1. Check: • Clutch spring Damage → Replace the clutch spring. 2. Measure: • Clutch spring free length Out of specification → Replace the clutch spring.

  • Page 162: Checking The Clutch Push Rods

    CLUTCH CHECKING THE CLUTCH PUSH RODS 1. Check: • Push lever shaft • Push rod 2 • Ball → Cracks/damage/wear Replace defective part(s). CHECKING THE PRIMARY DRIVE GEAR 1. Check: • Primary drive gear Damage/wear → Replace the primary drive and primary driven gears as a set.
  • Page 163 CLUTCH 3. Tighten: • Clutch boss nut • Primary drive gear nut Clutch boss nut 75 Nm (7.5 m•kg, 55 ft•lb) Primary drive gear nut 80 Nm (8.0 m•kg, 59 ft•lb) NOTE: NOTE: • While holding the clutch boss with the univer- sal clutch holder , tighten the clutch boss nut.
  • Page 164 CLUTCH 7. Install: • Bearing • Oil seal • Circlip • Torsion spring • Push lever shaft • Bolt • Clutch cable NOTE: NOTE: After installing the clutch cable, bend the push lever shaft tab along a flat side of the nut. 8.
  • Page 165 CLUTCH 11.Adjust: • Push lever position a. Loosen the locknut b. Turn the adjusting screw in or out until the marks are aligned. c. Hold the adjusting screw to prevent it from moving and then tighten the locknut to specification. 8 Nm (0.8 m•kg, 5.9 ft•lb) CAUTION: Do not overtighten the locknut since this...

  • Page 166: Oil Pump And Blancer Weight Gear

    OIL PUMP AND BLANCER WEIGHT GEAR OIL PUMP AND BLANCER WEIGHT GEAR 6 Nm (0.6 m•kg, 4.4 ft•lb) 55 Nm (5.5 m•kg, 41 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the oil pump and bal- Remove the parts in the order listed. ancer weight gear Right crankcase cover Refer to “CLUTCH”.
  • Page 167 OIL PUMP AND BLANCER WEIGHT GEAR 6 Nm (0.6 m•kg, 4.4 ft•lb) 55 Nm (5.5 m•kg, 41 ft•lb) Order Job/Parts to remove Q’ty Remarks Balancer drive gear Oil strainer Spacer For installation, reverse the removal procedure. 4-51...
  • Page 168 OIL PUMP AND BLANCER WEIGHT GEAR 7 Nm (0.7 m•kg, 5.0 ft•lb) Order Job/Parts to remove Q’ty Remarks Disassembling the oil pump Remove the parts in the order listed. Oil pump housing Dowel pin Outer rotor Inner rotor Dowel pin Shaft Oil pump cover For assembly, reverse the disassembly...

  • Page 169: Removing The Balancer Weight Gear And Oil Pump

    OIL PUMP AND BLANCER WEIGHT GEAR REMOVING THE BALANCER WEIGHT GEAR AND OIL PUMP 1. Straighten the lock washer tab. 2. Remove: • Balancer weight gear nut • Lock washer • Balancer weight gear NOTE: NOTE: Place the aluminum plate between balancer drive gear and balancer weight gear...

  • Page 170: Checking The Balancer Weight Gear

    OIL PUMP AND BLANCER WEIGHT GEAR Inner-rotor-to-outer-rotor-tip clearance 0.150 mm (0.0059 in) Limit 0.23 mm (0.0091 in) Outer-rotor-to-oil-pump-housing clearance 0.100 ~ 0.151 mm (0.0039 ~ 0.0059 in) Limit 0.22 mm (0.0087 in) Oil-pump-housing-to-inner-and- outer-rotor clearance 0.04 ~ 0.09 mm (0.0016 ~ 0.0035 in) Limit 0.16 mm (0.0063 in) 3.

  • Page 171: Assenbling The Balancer Drive Gear

    OIL PUMP AND BLANCER WEIGHT GEAR ASSENBLING THE BALANCER DRIVE GEAR 1. Assemble: • Dowel pin • Compression spring NOTE: NOTE: Install the dowel pins and compression springs alternately as shown as. 2. Assemble: • Buffer boss INSTALLING THE OIL PUMP 1.

  • Page 172: Installing The Balancer Weight Gear

    OIL PUMP AND BLANCER WEIGHT GEAR INSTALLING THE BALANCER WEIGHT GEAR 1. Install: • Balancer weight gear • Lock washer • Balancer weight gear nut 2. Tighten: • Balancer weight gear nut Balancer weight gear nut 55 Nm (5.5 m•kg, 41 ft•lb) NOTE: NOTE: •...

  • Page 173: Shift Shaft

    SHIFT SHAFT SHIFT SHAFT 10 Nm (1.0 m•kg, 7.4 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) Order Job/Parts to remove Q’ty Remarks Removing the shift shaft and Remove the parts in the order listed. stopper lever Right crankcase cover Refer to “CLUTCH”. Clutch Shift pedal Shift shaft assembly...

  • Page 174: Checking The Shift Shaft

    SHIFT SHAFT CHECKING THE SHIFT SHAFT 1. Check: • Shift shaft • Shift lever Bends/damage/wear → Replace. • Shift lever spring Damage/wear → Replace. CHECKING THE STOPPER LEVER 1. Check: • Stopper lever Bends/damage → Replace. Roller turns roughly → Replace the stopper lever.
  • Page 175 SHIFT SHAFT 4. Check: • When the gear position is in Neutral, check the length ( ) between the tip of the shift lever and dowel pin are equal. → Replace the shift shaft. If not 5. Install: • Shift pedal 6.

  • Page 176: Pickup Coil Rotor And Starter Clutch

    PICKUP COIL ROTOR AND STARTER CLUTCH PICKUP COIL ROTOR AND STARTER CLUTCH 7 Nm (0.7 m•kg, 5.2 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 60 Nm (6.0 m•kg, 44 ft•lb) Order Job/Parts to remove...
  • Page 177 PICKUP COIL ROTOR AND STARTER CLUTCH 7 Nm (0.7 m•kg, 5.2 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 30 Nm (3.0 m•kg, 22 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 60 Nm (6.0 m•kg, 44 ft•lb) Order Job/Parts to remove Q’ty...

  • Page 178: Removing The Pickupcoil Rotor

    PICKUP COIL ROTOR AND STARTER CLUTCH REMOVING THE PICKUPCOIL ROTOR 1. Remove: • Pickup coil rotor bolt • Washer NOTE: NOTE: • Loosen the pickup coil rotor bolt while holding the rotor with a sheave holder • Do not allow the sheave holder to touch the projection on the rotor Sheave holder 90890-01701...

  • Page 179: Checking The Starter Clutch

    PICKUP COIL ROTOR AND STARTER CLUTCH CHECKING THE STARTER CLUTCH 1. Check: • Starter clutch rollers Damage/wear → Replace the starter clutch. 2. Check: • Starter idle gear • Starter wheel gear • Starter clutch gear Burrs/chips/roughness/wear → Replace the defective part(s). 3.

  • Page 180: Installing The Pickup Coil Rotor

    PICKUP COIL ROTOR AND STARTER CLUTCH INSTALLING THE PICKUP COIL ROTOR 1. Install: • Washer • Bearing • Starter wheel gear • Starter idle gear 2 2. Install: • Woodruff key • Pickup coil rotor • Washer • Pickup coil rotor bolt NOTE: NOTE: •...
  • Page 181 PICKUP COIL ROTOR AND STARTER CLUTCH 4. Install: • Stater coil • Pickup coil 5. Tighten: • Stater coil bolts • Pickup coil bolts • Left crankcase cover bolt Stater coil bolt 10 Nm (1.0 m•kg, 7.4 ft•lb) ® LOCTITE Pickup coil bolt 10 Nm (1.0 m•kg, 7.4 ft•lb) ®...

  • Page 182: Crankcase

    CRANKCASE CRANKCASE 8 Nm (0.8 m•kg, 5.9 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) Order Job/Parts to remove Q’ty Remarks Separating the crankcase Remove the parts in the order listed. Engine Refer to “ENGINE REMOVAL”. Cylinder head Refer to “CYLINDER HEAD”.
  • Page 183 CRANKCASE 8 Nm (0.8 m•kg, 5.9 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) 20 Nm (2.0 m•kg, 14.8 ft•lb) Order Job/Parts to remove Q’ty Remarks Spacer For installation, reverse the removal procedure. 4-67...
  • Page 184 CRANKCASE Order Job/Parts to remove Q’ty Remarks Removing the bearing Remove the parts in the order listed. Crankshaft assembly Refer to “CRANKSHAFT ASSEMBLY”. Main axle assembly/drive axle assem- Refer to “TRANSMISSION”. Oil seal Bearing For installation, reverse the removal procedure. 4-68...

  • Page 185: Disassembling The Crankcase

    CRANKCASE DISASSEMBLING THE CRANKCASE 1. Remove: • Timing chain guide (intake side) • Timing chain • Crankshaft sprocket 2. Remove: • Neutral switch • Crankcase bolts M6 × 70 mm • Copper washers • Crankcase bolts M6 × 60 mm •...

  • Page 186: Checking The Crankcase

    1. Apply: • Yamaha bond No.1215 (Three Bond ® No.1215 (onto the crankcase mating surfaces) Yamaha bond No.1215 ® (Three Bond No.1215 90890-85505 NOTE: NOTE: Do not allow any sealant to come into contact with the oil gallery. 2. Install: •...
  • Page 187 CRANKCASE 4. Install: • Crankcase bolts M6 × 70 mm • Copper washers to • Crankcase bolts M6 × 60 mm • Crankcase bolts M6 × 55 mm • Crankcase bolts M6 × 45 mm 5. Tighten: • Crankcase bolts Crankcase bolt 10 Nm (1.0 m•kg, 7.4 ft•lb) NOTE:...

  • Page 188: Crankshaft Assembly

    CRANKSHAFT ASSEMBLY CRANKSHAFT ASSEMBLY Order Job/Parts to remove Q’ty Remarks Removing the crankshaft assembly Remove the parts in the order listed. Crankcase Refer to “CRANKCASE”. Balancer weight Crankshaft assembly Dowel pin Plunger seal Bearing For installation, reverse the removal procedure. 4-72...

  • Page 189: Removing The Crankshaft Assembly

    CRANKSHAFT ASSEMBLY REMOVING THE CRANKSHAFT ASSEMBLY 1. Remove: • Balancer weight • Crankshaft assembly NOTE: NOTE: • Remove the crankshaft assembly with the crankcase separating tool • Make sure the crankcase separating tool is centered over the crankshaft assembly. Crankcase separating tool 90890-01135 Crankcase separator YU-01135-B...

  • Page 190: Checking The Timing Chain, Crankshaft Sprocket And Timing Chain Guide

    CRANKSHAFT ASSEMBLY 2. Measure: • Big end side clearance Out of specification → Replace the big end bearing, crankshaft pin, or connecting rod. Big end side clearance D 0.350 ~ 0.650 mm (0.0138 ~ 0.0256 in) 3. Measure: • Crankshaft width Out of specification →...

  • Page 191: Installing The Plunger Seal

    CRANKSHAFT ASSEMBLY 3. Check: • Timing chain guide (intake side) Damage/wear → Replace the timing chain guide (intake side) INSTALLING THE PLUNGER SEAL 1. Install: • Compression spring • Plunger seal • Dowel pin Check the plunger seal smooth operation pushing the plunger seal by your finger.
  • Page 192 CRANKSHAFT ASSEMBLY CAUTION: To avoid scratching the crankshaft and to ease the installation procedure, lubricate the oil seal lips with lithium-soap-based grease and each bearing with engine oil. NOTE: NOTE: Hold the connecting rod at top dead center (TDC) with one hand while turning the nut of the crankshaft installer bolt with the other.

  • Page 193: Transmission

    TRANSMISSION TRANSMISSION Order Job/Parts to remove Q’ty Remarks Removing the transmission, shift Remove the parts in the order listed. drum assembly, and shift forks Crankcase Separate. Refer to “CRANKCASE”. Shift fork guide bar Shift drum assembly Shift fork-3 (R) Shift fork-2 (C) Shift fork-1 (L) Main axle assembly Drive axle assembly...
  • Page 194 TRANSMISSION Order Job/Parts to remove Q’ty Remarks Disassembling the transmission Remove the parts in the order listed. 2nd pinion gear 5th pinion gear 3rd pinion gear Circlip/washer 4th pinion gear Main axle Plain washer 1st wheel gear 4th wheel gear Circlip/washer 3rd wheel gear/collar Claw washer 1...
  • Page 195 TRANSMISSION Order Job/Parts to remove Q’ty Remarks Drive axle For installation, reverse the removal procedure. 4-79...

  • Page 196: Removing The Transmission

    TRANSMISSION REMOVING THE TRANSMISSION 1. Remove: • Shift fork guide bar • Shift drum assembly • Shift fork 3 (R) • Shift fork 2 (C) • Shift fork 1 (L) 2. Remove: • Transmission CHECKING THE SHIFT FORKS The following procedure applies to all of the shift forks.

  • Page 197: Checking The Shift Drum Assembly

    TRANSMISSION CHECKING THE SHIFT DRUM ASSEMBLY 1. Check: • Shift drum groove Damage/scratches/wear → Replace the shift drum assembly. • Shift drum segment Damage/wear → Replace the shift drum assembly. • Shift drum bearing Damage/pitting → Replace the shift drum assembly.
  • Page 198 TRANSMISSION 4. Check: • Transmission gear engagement (each pinion gear to its respective wheel gear) Incorrect → Reassemble the transmission axle assemblies. NOTE: NOTE: When reassembling the main axle, press the 2nd pinion gear onto it as shown. 102.2 ~ 102.4 mm (4.02 ~ 4.03 in) 5.

  • Page 199: Carb

    CARB CARBURETOR EBS00141 CARBURETOR CARBURETOR 2 Nm (0.2 m•kg, 1.5 ft•lb) 3.5 Nm (0.4 m•kg, 2.6 ft•lb) 3.5 Nm (0.4 m•kg, 2.6 ft•lb) Order Job/Part Q’ty Remarks Remove the parts in the order listed. Removing a carburetor Seat/front fender/rear fender/air filter Refer to “SEAT, FENDERS AND FUEL case TANK”...
  • Page 200 CARB CARBURETOR EBS00144 Order Job/Part Q’ty Remarks Remove the parts in the order listed. Disassembling the carburetor Drain hose Throttle stop screw Cover Diaphragm spring Piston valve Jet needle Cover Spring Coasting enricher diaphragm Coasting enricher jet (P. A. J. 2) Starter plunger Carburetor warmer positive lead Carburetor warmer...
  • Page 201 CARB CARBURETOR Order Job/Part Q’ty Remarks Float Needle valve seat set Main jet Needle jet holder Needle jet Pilot jet Starter jet For assembly, reverse the disassembly procedure.

  • Page 202: Checking The Carburetor

    CARB CARBURETOR EBS00148 CHECKING THE CARBURETOR 1. Check: • carburetor body • float chamber Cracks/damage → Replace. • fuel passage Contamination → Clean as indicated. • fuel chamber body Contamination → Clean. a. Wash the carburetor in a petroleum based solvent.
  • Page 203 CARB CARBURETOR 5. Check: • piston valve movement Sticks → Replace. Insert the piston valve into the carburetor body, and check for free movement. 6. Check: • throttle valve movement Sticks → Replace. 7. Check: • cover • diaphragm spring Cracks/damage →...

  • Page 204: Assembling The Carburetor

    CARB CARBURETOR 11.Check: • starter plunger • starter plunger spring Bends/cracks/damage → Replace. EBS00150 ASSEMBLING THE CARBURETOR CAUTION: Before reassembling, wash all of the parts in a clean petroleum based solvent. 1. Measure: • float height Out of specification → Adjust. Float height (F.H) 13.0 mm (0.51 in) a.

  • Page 205: Installing The Carburetor Joint

    CARB CARBURETOR INSTALLING THE CARBURETOR JOINT 1. Install: • clamp NOTE: NOTE: Align the projection on the carburetor joint with the slot in the clamp. 2. Install: • carburetor joint NOTE: NOTE: Align the projection on the cylinder head with the slot in the carburetor joint.

  • Page 206: Chas

    CHAS FRONT AND REAR WHEELS EBS00378 CHASSIS FRONT AND REAR WHEELS FRONT WHEELS 28 Nm (2.8 m•kg, 21 ft•lb) 70 Nm (7.0 m•kg, 52 ft•lb) 28 Nm (2.8 m•kg, 21 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) Order Job/Part Q’ty Remarks Removing the front wheels Remove the parts in the order listed.
  • Page 207 CHAS FRONT AND REAR WHEELS 28 Nm (2.8 m•kg, 21 ft•lb) 70 Nm (7.0 m•kg, 52 ft•lb) 28 Nm (2.8 m•kg, 21 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) Order Job/Part Q’ty Remarks Brake caliper assembly NOTE: NOTE: Do not squeeze the brake lever when the brake caliper is off of the brake discs as the brake pads will be forced shut.

  • Page 208: Rear Wheels

    CHAS FRONT AND REAR WHEELS REAR WHEELS 120 Nm (12.0 m•kg, 89 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) Order Job/Part Q’ty Remarks Removing the rear wheels Remove the parts in the order listed. Place the machine on a level surface. WARNING Securely support the machine so there is no danger of it falling over.

  • Page 209: Checking The Wheels

    CHAS FRONT AND REAR WHEELS EBS00383 CHECKING THE WHEELS 1. Check: • wheels 2. Measure: • wheel runout Over the specified limit → Replace the wheel or check the wheel bearing play Wheel runout limit Radial : 2.0 mm (0.08 in) Lateral : 2.0 mm (0.08 in) 3.

  • Page 210: Checking The Brake Discs

    CHAS FRONT AND REAR WHEELS 2. Check: • wheel bearings Wheel hub play/wheel turns roughly → Replace. a. Clean wheel hub exterior. b. Drive bearing out by pushing spacer aside and tapping around perimeter of bearing inner race. Use soft metal drift punch and hammer.

  • Page 211: Installing The Front Wheel Hub Bearings

    CHAS FRONT AND REAR WHEELS INSTALLING THE FRONT WHEEL HUB BEARINGS 1. Install: • bearings NOTE: NOTE: Face the oil seal side of the bearing inward. INSTALLING THE FRONT BRAKE DISCS 1. Install: • brake discs NOTE: NOTE: Install the brake disc with its spot-faced side facing the bolt heads.

  • Page 212: Installing The Wheel Hubs

    CHAS FRONT AND REAR WHEELS EBS00390 INSTALLING THE WHEEL HUBS 1. Install: • front axle nuts Front axle nut 70 Nm (7.0 m•kg, 52 ft•lb) • rear axle nuts Rear axle nut 120 Nm (12.0 m•kg, 89 ft•lb) • cotter pins NOTE: NOTE: •...

  • Page 213: Rear Axle And Rear Axle Hub

    CHAS REAR AXLE AND REAR AXLE HUB EBS00382 REAR AXLE AND REAR AXLE HUB 34 Nm (3.4 m•kg, 25 ft•lb) 7 Nm (0.7 m•kg, 5.2 ft•lb) 28 Nm (2.8 m•kg, 21 ft•lb) 55 Nm (5.5 m•kg, 41 ft•lb) 140 Nm (14.0 m•kg, 103 ft•lb) Order Job/Part Q’ty...
  • Page 214 CHAS REAR AXLE AND REAR AXLE HUB 34 Nm (3.4 m•kg, 25 ft•lb) 7 Nm (0.7 m•kg, 5.2 ft•lb) 28 Nm (2.8 m•kg, 21 ft•lb) 55 Nm (5.5 m•kg, 41 ft•lb) 140 Nm (14.0 m•kg, 103 ft•lb) Order Job/Part Q’ty Remarks Brake disc/brake disc bracket Rear axle...

  • Page 215: Removing The Rear Axle

    CHAS REAR AXLE AND REAR AXLE HUB EBS00393 REMOVING THE REAR AXLE 1. Place the machine on a level surface. 2. Loosen: • bolts 3. Remove: • nut NOTE: NOTE: • Apply the brake pedal so that the rear axle does not turn, when loosening the nut.

  • Page 216: Checking The Rear Axle

    CHAS REAR AXLE AND REAR AXLE HUB EBS00395 CHECKING THE REAR AXLE 1. Check: • rear axle runout Out of specification → Replace. WARNING Do not attempt to straighten a bent axle. Rear axle runout limit 1.5 mm (0.06 in) CHECKING THE DRIVEN SPROCKET 1.
  • Page 217 CHAS REAR AXLE AND REAR AXLE HUB 2. Tighten: • nut a. Tighten the nut with PTT wrench 46 or rear axle nut wrench to specification while holding the rear axle. 140 Nm (14.0 m•kg, 103 ft•lb) PTT wrench 46 90890-06588 Axle nut wrench (46 mm) YM-37134...

  • Page 218: Front And Rear Brakes

    CHAS FRONT AND REAR BRAKES EBS00400 FRONT AND REAR BRAKES FRONT BRAKE PADS 2.5 Nm (0.25 m•kg, 1.8 ft•lb) 17 Nm (1.7 m•kg, 13 ft•lb) 28 Nm (2.8 m•kg, 21 ft•lb) Order Job/Part Q’ty Remarks Removing the front brake pads Remove the parts in the order listed.

  • Page 219: Rear Brake Pads

    CHAS FRONT AND REAR BRAKES EBS00401 REAR BRAKE PADS 17 Nm (1.7 m•kg, 13 ft•lb) 34 Nm (3.4 m•kg, 25 ft•lb) Order Job/Part Q’ty Remarks Removing the rear brake pads Remove the parts in the order listed. Brake pad retaining bolt Lock washer Refer to “REPLACING THE REAR Brake pad...

  • Page 220: Replacing The Front Brake Pads

    CHAS FRONT AND REAR BRAKES EBS00402 CAUTION: Disc brake components rarely require dis- assembly. DO NOT: • disassemble components unless abso- lutely necessary; • use solvents on internal brake compo- nents; • use spent brake fluid for cleaning; (use only clean brake fluid) •...
  • Page 221 CHAS FRONT AND REAR BRAKES 2. Install: • brake pads • brake pad spring NOTE: NOTE: Always install new brake pads and brake pad spring as a set. a. Connect a suitable hose tightly to the brake caliper bleed screw .

  • Page 222: Replacing The Rear Brake Pads

    CHAS FRONT AND REAR BRAKES EBS00405 REPLACING THE REAR BRAKE PADS NOTE: NOTE: It is not necessary to disassemble the brake caliper and brake hose to replace the brake pads. 1. Remove: • brake pads wear limit NOTE: NOTE: Replace the brake pads as a set if either is found to be worn to the wear limit.
  • Page 223 CHAS FRONT AND REAR BRAKES 5. Check: • brake lever or brake pedal operation Soft or spongy feeling → Bleed the brake system. Refer to “BLEEDING THE HYDRAULIC BRAKE SYSTEM” in chapter 3. 6-18...

  • Page 224: Front Brake Master Cylinder

    CHAS FRONT AND REAR BRAKES EBS00407 FRONT BRAKE MASTER CYLINDER 7 Nm (0.7 m•kg, 5.2 ft•lb) 6 Nm (0.6 m•kg, 4.4 ft•lb) 27 Nm (2.7 m•kg, 20 ft•lb) Order Job/Part Q’ty Remarks Removing the front brake master Remove the parts in the order listed. cylinder Brake fluid Drain.
  • Page 225 CHAS FRONT AND REAR BRAKES EBS00409 Order Job/Part Q’ty Remarks Disassembling the front brake Remove the parts in the order listed. master cylinder Dust boot Refer to “ASSEMBLING THE FRONT Circlip BRAKE MASTER CYLINDER”. Brake master cylinder kit For assembly, reverse the disassembly procedure.

  • Page 226: Rear Brake Master Cylinder

    CHAS FRONT AND REAR BRAKES EBS00410 REAR BRAKE MASTER CYLINDER 7 Nm (0.7 m•kg, 5.2 ft•lb) 31 Nm (3.1 m•kg, 23 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) 73 Nm (7.3 m•kg, 54 ft•lb) Order Job/Part Q’ty Remarks Removing the rear brake master Remove the parts in the order listed.
  • Page 227 CHAS FRONT AND REAR BRAKES 7 Nm (0.7 m•kg, 5.2 ft•lb) 31 Nm (3.1 m•kg, 23 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) 73 Nm (7.3 m•kg, 54 ft•lb) Order Job/Part Q’ty Remarks Union bolt Refer to “INSTALLING Copper washer THE REAR BRAKE Brake hose Disconnect.
  • Page 228 CHAS FRONT AND REAR BRAKES EBS00411 17 Nm (1.7 m•kg, 13 ft•lb) Order Job/Part Q’ty Remarks Disassembling the rear brake Remove the parts in the order listed. master cylinder Hose joint Brake master cylinder kit Refer to “ASSEMBLING THE REAR Brake master cylinder BRAKE MASTER CYLINDER”.

  • Page 229: Checking The Master Cylinders

    CHAS FRONT AND REAR BRAKES EBS00413 CHECKING THE MASTER CYLINDERS 1. Check: • brake master cylinder Wear/scratches → Replace the brake mas- ter cylinder assembly. • brake master cylinder body Cracks/damage → Replace. • brake fluid delivery passage (brake master cylinder body) Blockage →...

  • Page 230: Assembling The Front Brake Master Cylinder

    CHAS FRONT AND REAR BRAKES EBS00415 ASSEMBLING THE FRONT BRAKE MASTER CYLINDER WARNING • All internal brake components should be cleaned and lubricated with new brake fluid only before installation. Recommended brake fluid DOT 4 • Whenever a master cylinder is disassem- bled, replace the piston seals and dust seals.

  • Page 231: Installing The Front Brake Master Cylinder

    CHAS FRONT AND REAR BRAKES 2. Tighten: • nut 17 Nm (1.7 m•kg, 13 ft•lb) EBS00418 INSTALLING THE FRONT BRAKE MASTER CYLINDER 1. Install: • brake master cylinder Brake master cylinder holder bolt 7 Nm (0.7 m•kg, 5.1 ft•lb) NOTE: NOTE: •...
  • Page 232 CHAS FRONT AND REAR BRAKES 3. Fill: • brake fluid reservoir Recommended brake fluid DOT 4 CAUTION: Brake fluid may damage painted surfaces or plastic parts. Always clean up spilled brake fluid immediately. WARNING • Use only the designated quality brake fluid: other brake fluids may deteriorate the rubber seals, causing leakage and poor brake performance.

  • Page 233: Installing The Rear Brake Master Cylinder

    CHAS FRONT AND REAR BRAKES EBS00419 INSTALLING THE REAR BRAKE MASTER CYLINDER 1. Install: • copper washers • brake hose • union bolt Union bolt 31 Nm (3.1 m•kg, 23 ft•lb) CAUTION: When installing the brake hose onto the brake master cylinder, make sure the brake pipe touches the projection shown.
  • Page 234 CHAS FRONT AND REAR BRAKES WARNING • Use only the designated quality brake fluid: other brake fluids may deteriorate the rubber seals, causing leakage and poor brake performance. • Refill with the same type of brake fluid: mixing brake fluids may result in a harm- ful chemical reaction and lead to poor brake performance.

  • Page 235: Front Brake Calipers

    CHAS FRONT AND REAR BRAKES EBS00421 FRONT BRAKE CALIPERS 17 Nm (1.7 m•kg, 13 ft•lb) 2.5 Nm (0.25 m•kg, 1.8 ft•lb) 28 Nm (2.8 m•kg, 21 ft•lb) 27 Nm (2.7 m•kg, 20 ft•lb) Order Job/Part Q’ty Remarks Removing the front brake calipers Remove the parts in the order listed.
  • Page 236 CHAS FRONT AND REAR BRAKES EBS00423 5 Nm (0.5 m•kg, 3.7 ft•lb) 17 Nm (1.7 m•kg, 13 ft•lb) 2.5 Nm (0.25 m•kg, 1.8 ft•lb) Order Job/Part Q’ty Remarks Disassembling the front brake Remove the parts in the order listed. calipers The following procedure applies to both of the front brake calipers.

  • Page 237: Rear Brake Caliper

    CHAS FRONT AND REAR BRAKES EBS00424 REAR BRAKE CALIPER 31 Nm (3.1 m•kg, 23 ft•lb) 34 Nm (3.4 m•kg, 25 ft•lb) Order Job/Part Q’ty Remarks Removing the rear brake caliper Remove the parts in the order listed. Brake fluid Drain. Refer to “BLEEDING THE HYDRAULIC BRAKE SYSTEM”...
  • Page 238 CHAS FRONT AND REAR BRAKES EBS00425 17 Nm (1.7 m•kg, 13 ft•lb) 5 Nm (0.5 m•kg, 3.7 ft•lb) 17 Nm (1.7 m•kg, 13 ft•lb) 15 Nm (1.5 m•kg, 11 ft•lb) Order Job/Part Q’ty Remarks Disassembling the rear brake caliper Remove the parts in the order listed. Adjusting bolt Locknut Parking brake arm...

  • Page 239: Removing The Parking Brake Cable

    CHAS FRONT AND REAR BRAKES REMOVING THE PARKING BRAKE CABLE 1. Loosen: • nut • adjusting bolt 2. Disconnect: • parking brake cable (from parking brake lever) 3. Disconnect: • parking brake cable (from rear brake) EBS00427 DISASSEMBLING THE FRONT AND REAR BRAKE CALIPERS 1.

  • Page 240: Checking The Front And Rear Brake Calipers

    CHAS FRONT AND REAR BRAKES EBS00429 CHECKING THE FRONT AND REAR BRAKE CALIPERS Recommended brake component replacement schedule Brake pads As required Piston seals, dust Every two years seals Brake hoses Every four years Replace when Brake fluid brakes are disassembled.

  • Page 241: Assembling The Front Brake Calipers

    CHAS FRONT AND REAR BRAKES EBS00431 ASSEMBLING THE FRONT BRAKE CALIPERS The following procedure applies to both of the front brake calipers. WARNING • All internal brake components should be cleaned and lubricated with new brake fluid only before installation. Recommended brake fluid DOT 4 •...
  • Page 242 CHAS FRONT AND REAR BRAKES 2. Install: • brake caliper piston 3. Install: • lock washer • brake pad retaining bolts Brake pad retaining bolt 17 Nm (1.7 m•kg, 13 ft•lb) 4. Bend the lock washer tabs along a flat side of the bolts.

  • Page 243: Installing The Front Brake Calipers

    CHAS FRONT AND REAR BRAKES EBS00434 INSTALLING THE FRONT BRAKE CALIPERS The following procedure applies to both of the front brake calipers. 1. Install: • brake caliper assembly • brake caliper mounting bolts Brake caliper mounting bolt 28 Nm (2.8 m•kg, 21 ft•lb) •...
  • Page 244 CHAS FRONT AND REAR BRAKES WARNING • Use only the designated quality brake fluid: other brake fluids may deteriorate the rubber seals, causing leakage and poor brake performance. • Refill with the same type of brake fluid: mixing brake fluids may result in a harm- ful chemical reaction and lead to poor brake performance.

  • Page 245: Installing The Rear Brake Caliper

    CHAS FRONT AND REAR BRAKES EBS00436 INSTALLING THE REAR BRAKE CALIPER 1. Install: • brake caliper assembly • brake caliper mounting bolts Brake caliper mounting bolt 34 Nm (3.4 m•kg, 25 ft•lb) • brake hose • copper washers • union bolt Union bolt 31 Nm (3.1 m•kg, 23 ft•lb) CAUTION:...
  • Page 246 CHAS FRONT AND REAR BRAKES WARNING • Use only the designated quality brake fluid: other brake fluids may deteriorate the rubber seals, causing leakage and poor brake performance. • Refill with the same type of brake fluid: mixing brake fluids may result in a harm- ful chemical reaction and lead to poor brake performance.

  • Page 247: Steering System

    CHAS STEERING SYSTEM EBS00444 STEERING SYSTEM HANDLEBAR 7 Nm (0.7 m•kg, 5.2 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) 4 Nm (0.4 m•kg, 3.0 ft•lb) 4 Nm (0.4 m•kg, 3.0 ft•lb) 7 Nm (0.7 m•kg, 5.2 ft•lb) Order Job/Part Q’ty Remarks Removing the handlebar Remove the parts in the order listed.
  • Page 248 CHAS STEERING SYSTEM 7 Nm (0.7 m•kg, 5.2 ft•lb) 20 Nm (2.0 m•kg, 15 ft•lb) 4 Nm (0.4 m•kg, 3.0 ft•lb) 4 Nm (0.4 m•kg, 3.0 ft•lb) 7 Nm (0.7 m•kg, 5.2 ft•lb) Order Job/Part Q’ty Remarks Handlebar grip Refer to “REMOVING THE HANDLEBAR GRIPS”...

  • Page 249: Removing The Clutch Switch

    CHAS STEERING SYSTEM EBS00446 REMOVING THE CLUTCH SWITCH 1. Remove: • clutch switch NOTE: NOTE: Push the fastener when removing the clutch switch out of the clutch lever holder. EBS00447 REMOVING THE HANDLEBAR GRIPS 1. Remove: • handlebar grips NOTE: NOTE: Blow compressed air between the handlebar and handlebar grip, and gradually push the...

  • Page 250: Installing The Handlebar

    CHAS STEERING SYSTEM EBS00449 INSTALLING THE HANDLEBAR 1. Install: • handlebar • handlebar holders Handleber holder 20 Nm (2.0 m•kg, 15 ft•lb) NOTE: NOTE: • Install the handlebar horizontally shown in the illustration. • The upper handlebar holder should be installed with the punched mark forward CAUTION:...

  • Page 251: Installing The Clutch Lever

    CHAS STEERING SYSTEM EBS00452 INSTALLING THE CLUTCH LEVER 1. Install: • handlebar switch • clutch lever • clutch lever bracket NOTE: NOTE: • Install the clutch lever bracket as shown. • Install the clutch lever at 10 degrees angle as shown. 53 ~ 54 mm (2.09 ~ 2.13 in) EBS00453 INSTALLING THE BRAKE MASTER...

  • Page 252: Steering Stem

    CHAS STEERING SYSTEM EBS00454 STEERING STEM 23 Nm (2.3 m•kg, 17 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) 35 Nm (3.5 m•kg, 26 ft•lb) Order Job/Part Q’ty Remarks Removing the steering stem Remove the parts in the order listed. Front fender Refer to “SEAT, FENDERS AND FUEL TANK”...

  • Page 253: Checking The Steering Stem

    CHAS STEERING SYSTEM EBS00456 CHECKING THE STEERING STEM 1. Check: • steering stem Bends/damage → Replace. WARNING Do not attempt to straighten a bent stem; this may dangerously weaken the stem. 2. Check: • oil seals • steering stem bushings Wear/damage →...

  • Page 254: Tie-Rods And Steering Knuckles

    CHAS STEERING SYSTEM EBS00460 TIE-RODS AND STEERING KNUCKLES 31 Nm (3.1 m•kg, 23 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) 48 Nm (4.8 m•kg, 35 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) Order Job/Part...

  • Page 255: Removing The Steering Knuckles

    CHAS STEERING SYSTEM EBS00461 REMOVING THE STEERING KNUCKLES 1. Remove: • steering knuckles NOTE: NOTE: Use a general puller to separate the ball joint and steering knuckle. EBS00462 CHECKING THE TIE-RODS 1. Check: • tie-rod free play and movement Free play → Replace the tie-rod end. Turns roughly →...

  • Page 256: Front Arms And Front Shock Absorber Assemblies

    FRONT ARMS AND FRONT SHOCK ABSORBER CHAS ASSEMBLIES EBS00468 FRONT ARMS AND FRONT SHOCK ABSORBER ASSEMBLIES 31 Nm (3.1 m•kg, 23 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) 48 Nm (4.8 m•kg, 35 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) 48 Nm (4.8 m•kg, 35 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb)
  • Page 257 FRONT ARMS AND FRONT SHOCK ABSORBER CHAS ASSEMBLIES 31 Nm (3.1 m•kg, 23 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) 48 Nm (4.8 m•kg, 35 ft•lb) 45 Nm (4.5 m•kg, 33 ft•lb) 48 Nm (4.8 m•kg, 35 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) 25 Nm (2.5 m•kg, 18 ft•lb) Order Job/Part...

  • Page 258: Removing The Front Arms

    FRONT ARMS AND FRONT SHOCK ABSORBER CHAS ASSEMBLIES EBS00469 REMOVING THE FRONT ARMS 1. Check: • front arm free play a. Check the front arm side play by moving it from side to side. If side play is noticeable, check the bush- ings.

  • Page 259: Checking The Ball Joints

    FRONT ARMS AND FRONT SHOCK ABSORBER CHAS ASSEMBLIES EBS00472 CHECKING THE BALL JOINTS The following procedure applies to both of the front arm ball joints. 1. Check: • ball joint Damage/pitting → Replace the front arm. Free play → Replace the front arm. Turns roughly →...

  • Page 260: Rear Shock Absorber, Swingarm And Drive Chain

    REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN REAR SHOCK ABSORBER, SWINGARM AND DRIVE CHAIN 55 Nm (5.5 m•kg, 41 ft•lb) 23 Nm (2.3 m•kg, 17 ft•lb) 100 Nm (10.0 m•kg, 74 ft•lb) 110 Nm (11.0 m•kg, 81 ft•lb) 55 Nm (5.5 m•kg, 41 ft•lb) Order Job/Part Q’ty...
  • Page 261 REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN 55 Nm (5.5 m•kg, 41 ft•lb) 23 Nm (2.3 m•kg, 17 ft•lb) 100 Nm (10.0 m•kg, 74 ft•lb) 110 Nm (11.0 m•kg, 81 ft•lb) 55 Nm (5.5 m•kg, 41 ft•lb) Order Job/Part Q’ty Remarks Drive chain guide 2...

  • Page 262: Handling The Rear Shock Absorber

    REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN HANDLING THE REAR SHOCK ABSORBER WARNING This rear shock absorber contains highly compressed nitrogen gas. Before handling the rear shock absorber read and make sure you understand the following informa- tion. The manufacturer cannot be held responsible for property damage or per- sonal injury that may result from improper handling of the rear shock absorber.

  • Page 263: Removing The Rear Shock Absorber

    REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN EBS00487 REMOVING THE REAR SHOCK ABSORBER 1. Remove: • rear shock absorber lower bolt • rear shock absorber upper bolt NOTE: NOTE: While removing the rear shock absorber lower bolt, hold the swingarm so that it does not drop down.

  • Page 264: Checking The Swingarm

    REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN Swingarm free play limit (at the end of the swingarm) 1.0 mm (0.04 in) b. Check the swingarm side play by mov- ing it from side to side. If side play is noticeable, check the spacer, bearings and frame pivot.

  • Page 265: Checking The Drive Chain

    REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN 4. Check: • oil seals Damage/wear → Replace. • bearings Damage/pitting → Replace. EBS00496 CHECKING THE DRIVE CHAIN 1. Measure: • 15-link section of the drive chain Out of specification → Replace the drive chain.
  • Page 266 REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN 3. Clean: • drive chain a. Wipe the drive chain with a clean cloth. b. Put the drive chain in kerosene and remove any remaining dirt. c. Remove the drive chain from the kerosene and completely dry it.

  • Page 267: Installing The Swingarm

    REAR SHOCK ABSORBER, SWINGARM AND CHAS DRIVE CHAIN 6. Check: • drive sprocket • driven sprocket wear → Replace More than 1/4 tooth the drive chain sprockets as a set. Bent teeth → Replace the drive chain sprockets as a set. Correct Drive chain roller Drive chain sprocket...

  • Page 268: Elec

    ELEC ELECTRICAL COMPONENTS EBS00500 ELECTRICAL ELECTRICAL COMPONENTS Main switch Tail/brake light Pickup coil/stator Rectifier/regulator Front brake light switch Headlight relay assembly Neutral indicator light Clutch switch Starting circuit cut-off Neutral switch Handlebar switch relay Rear brake light switch CDI unit Thermo switch Ignition coil Starter relay...

  • Page 269: Checking Switch Continuity

    ELEC CHECKING SWITCH CONTINUITY EBS01028 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 .

  • Page 270: Checking The Switches

    ELEC CHECKING THE SWITCHES EBS01029 CHECKING THE SWITCHES Check each switch for damage or wear, proper connections, and also for continuity between the ter- minals. Refer to “CHECKING SWITCH CONTINUITY”. Damage/wear → Repair or replace. Improperly connected → Properly connect. Incorrect continuity reading →...
  • Page 271 ELEC CHECKING THE SWITCHES Light switch Engine stop switch Start switch Main switch Front brake light switch Clutch switch Fuse Neutral switch Rear brake light switch...

  • Page 272: Checking The Bulbs And Bulb Sockets

    ELEC CHECKING THE BULBS AND BULB SOCKETS EBS01030 CHECKING THE BULBS AND BULB SOCKETS Check each bulb and bulb socket for damage or wear, proper connections, and also for conti- nuity between the terminals. Damage/wear → Repair or replace the bulb, bulb socket or both.
  • Page 273 ELEC CHECKING THE BULBS AND BULB SOCKETS WARNING Since the headlight bulb gets extremely hot, keep flammable products and your hands away from the bulb until it has cooled down. CAUTION: • Be sure to hold the socket firmly when removing the bulb.

  • Page 274: 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 Analog pocket tester YU-03112-C...

  • Page 275: Ignition System

    ELEC IGNITION SYSTEM EBS00503 IGNITION SYSTEM CIRCUIT DIAGRAM Pickup coil CDI unit Stator coil Ignition coil Main switch Spark plug Battery positive lead Engine stop switch Battery Ground Fuse...

  • Page 276: Troubleshooting

    ELEC IGNITION SYSTEM EBS01045 EBS01044 TROUBLESHOOTING 2. Battery • Check the condition of the battery. The ignition system fails to operate (no Refer to “CHECKING AND CHARGING spark or intermittent spark). THE BATTERY” in chapter 3. Check: Minimum open-circuit voltage 1.
  • Page 277 ELEC IGNITION SYSTEM EBS01034 EAS00745 4. Ignition spark gap 5. Spark plug cap resistance The following procedure applies to all of the The following procedure applies to all of the spark plugs. spark plug caps. • Disconnect the spark plug cap from the •...
  • Page 278 ELEC IGNITION SYSTEM EBS01038 EBS01041 6. Ignition coil resistance 7. Main switch • Disconnect the ignition coil coupler from the • Check the main switch for continuity. ignition coil. Refer to “CHECKING THE SWITCHES”. • Connect the pocket tester (Ω × 1) to the •...
  • Page 279 ELEC IGNITION SYSTEM EBS01047 10. Wiring • Check the entire ignition system’s wiring. Refer to “CIRCUIT DIAGRAM”. • Is the ignition system’s wiring properly con- nected and without defects? Replace Properly connect or unit. repair the ignition system’s wiring. 7-12...

  • Page 280: Electric Starting System

    ELEC ELECTRIC STARTING SYSTEM EBS00506 ELECTRIC STARTING SYSTEM CIRCUIT DIAGRAM Main switch Starting circuit cut-off relay Battery positive lead Clutch switch Battery Neutral switch Fuse Engine stop switch Starter relay Start switch Starter motor Ground 7-13...

  • Page 281: Starting Circuit Cut-Off System Operation

    ELEC ELECTRIC STARTING SYSTEM EBS00508 STARTING CIRCUIT CUT-OFF SYSTEM OPERATION The starting circuit on this model consists of the starter motor, starter relay, clutch switch, and neutral switch. If the main switch is on and the engine stop switch is in the RUN position, the starter motor can be operated only if: The transmission is in neutral (the neutral switch is closed)

  • Page 282: Troubleshooting

    ELEC ELECTRIC STARTING SYSTEM EBS01050 EBS01044 TROUBLESHOOTING 2. Battery • Check the condition of the battery. The starter motor fails to turn. Refer to “CHECKING AND CHARGING THE BATTERY” in chapter 3. Check: 1. fuse Minimum open-circuit voltage 2. battery 12.8 V or more at 20°C (68°F) 3.
  • Page 283 ELEC ELECTRIC STARTING SYSTEM EBS01052 EBS01053 4. Starting circuit cut-off relay 5. Starting circuit cut-off relay (diode) • Remove the starting circuit cut-off relay • Remove the starting circuit cut-off relay from the wire harness. from the wire harness. • Connect the pocket tester (Ω × 1) and bat- •...
  • Page 284 ELEC ELECTRIC STARTING SYSTEM EBS01054 EBS01042 6. Starter relay 8. Engine stop switch • Disconnect the starter relay coupler from • Check the engine stop switch for continuity. the wire harness. Refer to “CHECKING THE SWITCHES”. • Connect the pocket tester (Ω × 1) and bat- •...
  • Page 285 ELEC ELECTRIC STARTING SYSTEM EBS01059 12. Wiring • Check the entire starting system’s wiring. Refer to “CIRCUIT DIAGRAM”. • Is the starting system’s wiring properly con- nected and without defects? The starting system Properly connect or circuit is OK. repair the starting system’s wiring.

  • Page 286: Starter Motor

    ELEC STARTER MOTOR EBS01061 STARTER MOTOR 10 Nm (1.0 m•kg, 7.4 ft•lb) 7 Nm (0.7 m•kg, 5.2 ft•lb) 10 Nm (1.0 m•kg, 7.4 ft•lb) Order Job/Part Q’ty Remarks Removing the starter motor Remove the parts in the order listed. Exhaust pipe Refer to “ENGINE REMOVAL”...
  • Page 287 ELEC STARTER MOTOR EBS01062 Order Job/Part Q’ty Remarks Disassembling the starter motor Remove the parts in the order listed. Front bracket Tang washer Plate washer Circlip Refer to “ASSEMBLING THE STARTER MOTOR”. Rear bracket/Brush Armature assembly Starter motor yoke Brush/spring For assembly, reverse the disassembly procedure.

  • Page 288: Checking The Starter Motor

    ELEC STARTER MOTOR EBS01064 CHECKING THE STARTER MOTOR 1. Check: • commutator Dirt → Clean with 600-grit sandpaper. 2. Measure: • commutator diameter Out of specification → Replace the starter motor. Commutator wear limit 21 mm (0.83 in) 3. Measure: •...
  • Page 289 ELEC STARTER MOTOR b. If any resistance is out of specification, replace the starter motor. 5. Measure: • brush length Out of specification → Replace the brushes as a set. Brush length wear limit 3.5 mm (0.14 in) 6. Measure: •...

  • Page 290: Assembling The Starter Motor

    ELEC STARTER MOTOR EBS00515 ASSEMBLING THE STARTER MOTOR 1. Install: • brush spring • brush 2. Install: • armature coil 3. Install • O-rings to starter motor yoke 4. Install • Starter motor yoke NOTE: NOTE: Align the match marks on the starter motor york with the match marks...

  • Page 291: Charging System

    ELEC CHARGING SYSTEM EBS00516 CHARGING SYSTEM CIRCUIT DIAGRAM Stator coil Rectifier/regulator Battery positive lead Battery Fuse Ground 7-24...

  • Page 292: Troubleshooting

    ELEC CHARGING SYSTEM EBS01065 EBS01044 TROUBLESHOOTING 2. Battery • Check the condition of the battery. The battery is not being charged. Refer to “CHECKING AND CHARGING THE BATTERY” in chapter 3. Check: 1. fuse Minimum open-circuit voltage 2. battery 12.8 V or more at 20°C (68°F) 3.
  • Page 293 ELEC CHARGING SYSTEM EBS01066 EBS01100 3. Charging voltage 4. Stator coil resistance • Connect the engine tachometer to on to the • Disconnect the AC magneto coupler from ignition coil. the wire harness. • Connect the pocket tester (Ω × 1) to the •...

  • Page 294: Lighting System

    ELEC LIGHTING SYSTEM EBS00518 LIGHTING SYSTEM CIRCUIT DIAGRAM Stator coil Tail/brake light Rectifier/regulator Light switch Main switch Headlight relay Battery positive lead Headlight Battery Ground Fuse 7-27...

  • Page 295: Troubleshooting

    ELEC LIGHTING SYSTEM EBS01067 EAS00776 TROUBLESHOOTING 2. Stator coil resistance • Disconnect the AC magneto coupler from Any of the following fail to light: head- the wire harness. light, tail/brake light. • Connect the pocket tester (Ω × 1) to the charging coils.

  • Page 296: Checking The Lighting System

    ELEC LIGHTING SYSTEM EBS01069 2. Voltage 3. Wiring • Connect the pocket tester (AC 20 V) to the • Check the entire lighting system’s wiring. headlight couplers as shown. Refer to “CIRCUIT DIAGRAM”. • Is the lighting system’s wiring properly con- When the light switch is set to “LO”...
  • Page 297 ELEC LIGHTING SYSTEM 2. The tail/brake light fails to come on. 3. Voltage 1. Tail/brake light bulb and bulb socket • Connect the pocket tester (AC 20 V) to the (4D31) tail/brake light coupler as shown. • Check the tail/brake light bulb and socket Tail/brake light coupler (wire harness side) for continuity.

  • Page 298: Signal System

    ELEC SIGNAL SYSTEM EBS00521 SIGNAL SYSTEM CIRCUIT DIAGRAM Main switch Rear brake light switch Battery positive lead Front brake light switch Battery Tail/brake light Fuse Ground Neutral indicator light Neutral switch 7-31...

  • Page 299: Troubleshooting

    ELEC SIGNAL SYSTEM EBS01073 EBS01044 TROUBLESHOOTING 2. Battery • Check the condition of the battery. Any of the following fail to light: brake Refer to “CHECKING AND CHARGING light or an indicator light. THE BATTERY” in chapter 3. Check: Minimum open-circuit voltage 1.

  • Page 300: Checking The Signaling System

    ELEC SIGNAL SYSTEM EBS01075 3. Brake light switches CHECKING THE SIGNALING SYSTEM EBS01076 • Check the brake light switches for continuity. 1. The tail/brake light fails to come on. Refer to “CHECKING THE SWITCHES”. • Is the brake light switch OK? 1.
  • Page 301 ELEC SIGNAL SYSTEM EBS01077 3. Voltage 2. The neutral indicator light fails to come on. • Connect the pocket tester (DC 20 V) to the 1. Neutral indicator light bulb and socket indicator light coupler (wire harness side) • Check the neutral indicator light bulb and as shown.
  • Page 302 ELEC SIGNAL SYSTEM EBS01083 2. Carburetor warmer 3. The carburetor heater fails to come on. • Remove the carburetor heating element 1. Thermo switch from the carburetor. • Disconnect the thermo switch from the wire- • Connect the pocket tester (Ω × 1) to the car- harness.

  • Page 303: Starting Failure/Hard Starting

    TRBL STARTING FAILURE/HARD STARTING SHTG EBS00537 TROUBLESHOOTING NOTE: The following troubleshooting does not cover all the possible causes of trouble. It should be helpful, however, as a guide to troubleshooting. Refer to the relative procedure in this manual for check, adjustment and replacement of parts.

  • Page 304: Trbl Shtg

    STARTING FAILURE/HARD STARTING/POOR IDLE SPEED TRBL PERFORMANCE/POOR MEDIUM AND HIGH-SPEED PERFORMANCE SHTG COMPRESSION SYSTEM Cylinder and cylinder head Piston and piston rings • Loose spark plug • Improperly installed piston ring • Loose cylinder head or cylinder • Worn, fatigued or broken piston ring •...

  • Page 305: Faulty Gear Shifting

    FAULTY GEAR SHIFTING/ TRBL CLUTCH SLIPPING/DRAGGING SHTG EBS00541 FAULTY GEAR SHIFTING HARD SHIFTING Refer to “CLUTCH DRAGGING”. SHIFT PEDAL DOES NOT MOVE Shift shaft Transmission • Bent shift shaft • Seized transmission gear Shift drum and shift forks • Jammed impurities •...

  • Page 306: Overheating

    FAULTY BRAKE OVERHEATING/ TRBL SHOCK ABSORBER MALFUNCTION SHTG EBS00547 OVERHEATING OVERHEATING Ignition system Engine oil • Improper spark plug gap • Improper oil level • Improper spark plug heat range • Improper oil viscosity • Faulty CDI unit • Inferior oil quality Fuel system Brake •...

  • Page 307: Unstable Handling

    UNSTABLE HANDLING/ TRBL LIGHTING SYSTEM SHTG EBS00552 UNSTABLE HANDLING UNSTABLE HANDLING Handlebar Wheels • Improperly installed or bent • Deformed wheel Steering • Loose bearing • Incorrect toe-in • Bent or loose wheel axle • Bent steering stem • Excessive wheel runout •...
  • Page 310 YAMAHA MOTOR CO., LTD. 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN U.S.A.
  • Page 311 YFM250RX WIRING DIAGRAM Pickup coil Stator coil Rectifier/regulator Main switch Battery positive lead Battery Fuse Starter relay Starter motor CDI unit Ignition coil Spark plug Starting circuit cut-off relay Clutch switch Thermo switch Carburetor warmer Neutral indicator light Neutral switch Rear brake light switch Front brake light switch Tail/brake light...

This manual is also suitable for:

2008 raptor 250

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