Yamaha RAPTOR 50- Manuals

EBS00007 TABLE OF CONTENTS GENERAL INFORMATION GEN INFO 1 SPECIFICATIONS SPEC 2 PERIODIC CHECKS AND ADJUSTMENTS CHK ADJ 3 ENGINE ENG 4 CARBURETOR CARB 5 DRIVE TRAIN DRIV 6 CHASSIS CHAS 7 ELECTRICAL ELEC 8 TROUBLESHOOTING TRBL SHTG 9 – +

ELECTRICAL SYSTEM ................................................................................. 3-33 CHECKING AND CHARGING THE BATTERY ....................................... 3-33CHECKING THE FUSE ........................................................................... 3-37 CHAPTER 4 ENGINE E...

1 - 1 GEN INFO EBS00009 GENERAL INFORMATION MACHINE IDENTIFICATION EBS00010 VEHICLE IDENTIFICATION NUMBER The vehicle identification number 1 is stamped into the left side of the frame. EBS00011 MODEL LABEL The model label 1 is affixed to the frame. This information will be needed to order sparepart...

1 - 2 GEN INFO IMPORTANT INFORMATION EBS00013 IMPORTANT INFORMATION PREPARATION FOR REMOVAL AND DISASSEMBLY 1. Before removal and disassembly remove all dirt, mud, dust and foreign material. 2. Use only the proper tools and cleaning equipment. Refer to “SPECIAL TOOLS”. 3. When disassembling always k...

1 - 3 GEN INFO IMPORTANT INFORMATION EBS00016 LOCK WASHERS/PLATES AND COTTER PINS After removal, replace all lock washers/plates 1 and cotter pins. After the bolt or nut has been tightened to specification, bend the locktabs along a flat of the bolt or nut. EBS00017 BEARINGS AND OIL SEALS Install be...

1 - 4 GEN INFO IMPORTANT INFORMATION EBS00019 CHECKING THE CONNECTIONS Check the leads, couplers, and connectors forstains, rust, moisture, etc.1. Disconnect: • lead • coupler • connector 2. Check: • lead • coupler • connector Moisture → Dry with an air blower. Rust/stains → Connect and disconnect s...

1 - 5 GEN INFO SPECIAL TOOLS EBS00021 SPECIAL TOOLS The following special tools are necessary for complete and accurate tune-up and assembly. Useonly the appropriate special tools; this will help prevent damage caused by the use of inappropriatetools or improvised techniques. Special tools may diffe...

2 - 1 SPEC EBS01001 SPECIFICATIONS GENERAL SPECIFICATIONS Item Standard Model code 5YF1 Dimensions Overall length 1,537 mm (60.5 in) Overall width 825 mm (32.5 in) Overall height 915 mm (36.0 in) Seat height 618 mm (24.3 in) Wheelbase 1,030 mm (40.6 in) Minimum ground clearance 70 mm (2.76 in) Minim...

2 - 4 SPEC ENGINE SPECIFICATIONS EBS01002 ENGINE SPECIFICATIONS Item Standard Limit Cylinder head Warp limit ---- 0.05 mm (0.002 in) Cylinder Bore size 39.000 ~ 39.005 mm(1.5354 ~ 1.5356 in) 39.105 mm (1.5396 in) Taper limit ---- 0.05 mm (0.002 in) Maximum out-of-round ---- 0.01 mm (0.0004 in) Camsh...

2 - 5 SPEC ENGINE SPECIFICATIONS Rocker arm/rocker arm shaft Rocker arm inside diameter 10.000 ~ 10.015 mm(0.3937 ~ 0.3943 in) ---- Rocker arm shaft outside diameter 9.981 ~ 9.991 mm (0.3930 ~ 0.3933 in) ---- Rocker-arm-to-rocker-arm-shaft clearance 0.009 ~ 0.034 mm (0.0004 ~ 0.0013 in) 0.08 mm (0.0...

2 - 6 SPEC ENGINE SPECIFICATIONS Stem-to-guide clearance IN 0.010 ~ 0.037 mm (0.0004 ~ 0.0015 in) 0.08 mm (0.0031 in) EX 0.025 ~ 0.052 mm (0.0010 ~ 0.0020 in) 0.10 mm (0.0039 in) Stem runout limit ---- 0.02 mm (0.0008 in) Valve seat width IN 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in) 1.6 mm (0.0630 in) EX 0....

2 - 7 SPEC ENGINE SPECIFICATIONS Piston Piston to cylinder clearance 0.025 ~ 0.045 mm (0.0010 ~ 0.0018 in) 0.15 mm (0.0059 in) Piston size “D” 38.960 ~ 38.975 mm (1.5339 ~ 1.5344 in) ---- Measuring point “H” 5.0 mm (0.20 in) ---- Oversize 2nd 39.5 mm (1.56 in) ---- 4th 40.0 mm (1.57 in) ---- Piston ...

2 - 8 SPEC ENGINE SPECIFICATIONS Oil ring Dimensions (B × T) 2.0 × 2.0 mm (0.0787 × 0.0787 in) ---- End gap (installed) 0.20 ~ 0.70 mm(0.0079 ~ 0.0276 in) ---- Crankshaft Crank width “A” 40.20 ~ 40.25 mm (1.5827 ~ 1.5846 in) ---- Runout limit C1 ---- 0.05 mm (0.0020 in) C2 ---- 0.04 mm (0.0016 in) B...

2 - 9 SPEC ENGINE SPECIFICATIONS Clutch plate 1 Thickness 1.4 mm (0.055 in) ---- Quantity 1 ---- Maximum warpage ---- 0.06 mm (0.002 in) Clutch plate 2 Thickness 1.2 ~ 1.6 mm (0.047 ~ 0.063 in) ---- Quantity 3 ---- Maximum warpage ---- 0.06 mm (0.002 in) Clutch spring Free length 31.9 mm (1.26 in) 3...

2 - 10 SPEC ENGINE SPECIFICATIONS Oil pump Oil pump type Trochoid ---- Inner-rotor-to-outer-rotor-tip clearance 0.05 ~ 0.07 mm (0.002 ~ 0.003 in) 0.15 mm (0.006 in) Outer-rotor-to-oil-pump-housing clearance 0.013 ~ 0.036 mm (0.0005 ~ 0.0014 in) 0.106 mm (0.0042 in) Oil-pump-housing-to-inner-rotor-an...

2 - 11 SPEC CHASSIS SPECIFICATIONS EBS01003 CHASSIS SPECIFICATIONS Item Standard Limit Front suspension Shock absorber travel 60 mm (2.36 in) ---- Optional spring No ---- Rear suspension Shock absorber travel 58 mm (2.28 in) ---- Optional spring No ---- Front wheel Type Panel wheel ---- Rim size 7 ×...

2 - 12 SPEC ELECTRICAL SPECIFICATIONS EBS01004 ELECTRICAL SPECIFICATIONS Item Standard Limit Voltage 12 V ---- Ignition system Ignition timing (B.T.D.C.) 10°/1,700 r/min ---- Advanced timing (B.T.D.C.) 30°/5,000 r/min ---- Advancer type Electrical (analogue) ---- C.D.I. Magneto model/manufacturer F2...

2 - 13 SPEC ELECTRICAL SPECIFICATIONS Electric starter system Type Constant mesh ---- Starter motor Model/manufacturer ADB4A5/DENSO ---- Output 0.2 kW ---- Armature coil resistance 0.029 ~ 0.035 Ω at 20 °C (68 °F) ---- Brush overall length 6.0 mm (0.24 in) 3.5 mm (0.14 in) Spring force 3.24 ~ 4.22 N...

2 - 14 SPEC TIGHTENING TORQUES EBS01005 TIGHTENING TORQUES ENGINE TIGHTENING TORQUES Part to be tightened Part name Thread size Q’ty Tightening torque Remarks Nm m · kg ft · lb Cylinder head (exhaust pipe) Stud bolt M6 2 7 0.7 5.1 Intake and exhaust tappet cover — M45 2 18 1.8 13 Camshaft sprocket c...

2 - 15 SPEC TIGHTENING TORQUES EBS01006 CHASSIS TIGHTENING TORQUES Neutral switch — M10 1 20 2.0 14 Spark arrester tailpipe Screw M6 2 8 0.8 5.8 Purging bolt Bolt M6 1 10 1.0 7.2 Part to be tightened Thread size Tightening torque Remarks Nm m · kg ft · lb Engine and frame M8 33 3.3 24 Rear swingarm ...

2 - 17 SPEC HOW TO USE THE CONVERSION TABLE/ GENERAL TIGHTENING TORQUE SPECIFICATIONS EBS00022 HOW TO USE THE CONVERSION TABLE All specification data in this manual are listedin SI and METRIC UNITS. Use this table to convert METRIC unit data toIMPERIAL unit data. CONVERSION TABLE EBS00023 GENERAL TI...

2 - 18 SPEC LUBRICATION POINTS AND LUBRICANT TYPES EBS00024 LUBRICATION POINTS AND LUBRICANT TYPES ENGINE Lubrication points Lubricant Oil seal lips LS Bearings E O-rings LS Tappet cover thread E Crankshaft pin E Connecting rod (bearing) E Crankshaft, oil seal E Piston, piston ring E Piston pin E Va...

2 - 19 SPEC LUBRICATION POINTS AND LUBRICANT TYPES Final gear case and rear axle housing mating surface Sealant (Quick Gasket ® ) Yamaha Bond No.1215 Lubrication points Lubricant

2 - 20 SPEC OIL FLOW DIAGRAMS EBS00026 OIL FLOW DIAGRAMS 1 Camshaft 2 Crankshaft 3 Main axle 4 Drive axle

2 - 22 SPEC CABLE ROUTING EBS00028 CABLE ROUTING 1 Rear brake cable 2 Throttle cable 3 Fuel tank breather hose 4 Carburetor air vent hose 5 Final gear case breather hose 6 Crankcase breather hose 7 Starter relay 8 Starting circuit cut-off relay 9 Positive battery lead 0 Wire harness A Negative batte...

3 - 1 CHK ADJ EBS00029 PERIODIC CHECKS AND ADJUSTMENTS INTRODUCTION This chapter includes all information necessary to perform recommended checks and adjustments.These preventive maintenance procedures, if followed, will ensure more reliable machine operationand a longer service life. The need for c...

3 - 2 CHK ADJ SEAT, FENDERS AND FUEL TANK EBS00033 SEAT, FENDERS AND FUEL TANK SEAT AND FRONT PANEL 1 3 4 5 2 Order Job/Part Q’ty Remarks Removing the seat and front panel Remove the parts in the order listed. 1 Seat 1 NOTE: _ Pull back the seat lock lever, than pull upon the rear of the seat. 2 Fro...

3 - 3 CHK ADJ SEAT, FENDERS AND FUEL TANK EBS00037 FRONT FENDER T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) 4 1 2 3 T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) Order Job/Part Q’ty Remarks Removing the front fender Remove the parts in the order listed. Seat and front panel Refer to “SEAT AND FRONT PANEL”. 1 Fu...

3 - 4 CHK ADJ SEAT, FENDERS AND FUEL TANK EBS00039 REAR FENDER AND FOOTREST BOARDS 1 6 5 2 4 3 8 T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) 7 7 Order Job/Part Q’ty Remarks Removing the re...

3 - 6 CHK ADJ SEAT, FENDERS AND FUEL TANK EBS00042 FUEL TANK 2 1 Order Job/Part Q’ty Remarks Removing the fuel tank Remove the parts in the order listed. Seat and front panel Refer to “SEAT AND FRONT PANEL”. Front fender Refer to “FRONT FENDER”. 1 Fuel hose 1 Disconnect. NOTE: _ Before disconnecting...

3 - 7 CHK ADJ EBS00046 ENGINE ADJUSTING THE TIMING CHAIN TENSIONER 1. Remove: • C.D.I. magneto cover• camshaft sprocket cover Refer to “CYLINDER HEAD” in chapter 4. 2. Remove: • cap nut 1 3. Loosen: • locknut 2 • adjuster 3 4. Adjust: • timing chain tensioner ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ...

3 - 8 CHK ADJ 5. Install: • camshaft sprocket cover• C.D.I. magneto cover Refer to “CYLINDER HEAD” in chapter 4. ADJUSTING THE VALVE CLEARANCE NOTE: _ • The valve clearance must be adjusted when the engine is cool to the touch. • Adjust the valve clearance when the piston is at the Top Dead Center (...

3 - 10 CHK ADJ ADJUSTING THE VALVE CLEARANCE/ ADJUSTING THE ENGINE IDLING SPEED 4. Install: • camshaft sprocket cover• exhaust tappet cover• intake tappet cover• C.D.I. magneto cover Refer to “CYLINDER HEAD” in chapter 4. EBS00051 ADJUSTING THE ENGINE IDLING SPEED 1. Start the engine and let it warm...

3 - 11 CHK ADJ ADJUSTING THE ENGINE IDLING SPEED/ ADJUSTING THE THROTTLE LEVER FREE PLAY 6. Adjust: • throttle lever free play Refer to “ADJUSTING THE THROTTLELEVER FREE PLAY”. Throttle lever free play 1.5 ~ 5.0 mm (0.06 ~ 0.20 in) EBS00052 ADJUSTING THE THROTTLE LEVER FREE PLAY NOTE: _ Engine idlin...

3 - 12 CHK ADJ ADJUSTING THE SPEED LIMITER EBS00053 ADJUSTING THE SPEED LIMITER The speed limiter keeps the carburetor throttlefrom becoming fully-opened even when thethrottle lever is applied to the maximum posi-tion. Screwing in the adjuster stops the enginespeed from increasing.1. Measure: • spee...

3 - 13 CHK ADJ CHECKING THE SPARK PLUG EBS00057 CHECKING THE SPARK PLUG 1. Remove: • spark plug 2. Check: • spark plug type Incorrect → Change. 3. Check: • electrode 1 Wear/damage → Replace. • insulator 2 Abnormal color → Replace. Normal color is a medium-to-light tan color. 4. Clean: • spark plug (...

3 - 14 CHK ADJ CHECKING THE IGNITION TIMING EBS00058 CHECKING THE IGNITION TIMING NOTE: _ Engine idling speed and throttle cable free playshould be adjusted properly before checkingthe ignition timing. 1. Remove: • C.D.I. magneto cover Refer to “C.D.I. MAGNETO” in chapter 4. 2. Attach: • engine tach...

3 - 15 CHK ADJ MEASURING THE COMPRESSION PRESSURE EBS00061 MEASURING THE COMPRESSION PRESSURE NOTE: _ Insufficient compression pressure will result ina loss of performance. 1. Measure: • valve clearance Out of specification → Adjust. Refer to “ADJUSTING THE VALVECLEARANCE”. 2. Start the engine, warm...

3 - 16 CHK ADJ MEASURING THE COMPRESSION PRESSURE ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Set the main switch to “ON”. b. With the throttle wide open, crank the engine until the reading on the compressiongauge stabilizes. WARNING _ To prevent sparking, ground the spark pluglead before c...

3 - 17 CHK ADJ CHECKING THE ENGINE OIL LEVEL EBS00064 CHECKING THE ENGINE OIL LEVEL 1. Place the machine on a level surface.2. Check: • engine oil level Oil level should be between the maximum a mark and minimum b mark. Oil level low → Add oil to the proper level. NOTE: _ Do not screw the dipstick 1...

3 - 18 CHK ADJ CHANGING THE ENGINE OIL EBS00068 CHANGING THE ENGINE OIL 1. Start the engine, warm it up for several min- utes, and then turn it off. 2. Place a container under the engine oil drain bolt. 3. Remove: • dipstick 1 • engine oil drain bolt 2 (along with the gasket) 4. Drain: • engine oil ...

3 - 19 CHK ADJ CLEANING THE AIR FILTER ELEMENT EBS00071 CLEANING THE AIR FILTER ELEMENT NOTE: _ There is a check hose 1 at the bottom of the air filter case. If dust and/or water collects inthis hose, clean the air filter element and air fil-ter case. 1. Remove: • front panel Refer to “SEAT, FENDERS...

3 - 20 CHK ADJ CLEANING THE AIR FILTER ELEMENT/ CLEANING THE SPARK ARRESTER b. Squeeze the excess solvent out of the ele- ment and let it dry. CAUTION: _ Do not twist or wring out the element. Thiscould damage the foam material. c. Apply engine oil to the element. d. Squeeze out the excess oil. NOTE...

3 - 21 CHK ADJ c. Tap the tailpipe lightly with a soft-face ham- mer or suitable tool, then use a wire brushto remove any carbon deposits from thespark arrester por tion of the tailpipe and theinner contact surfaces of the muffler. d. Inser t the tailpipe into the muffler and align the screw holes. ...

3 - 22 CHK ADJ CHECKING THE FRONT AND REAR BRAKE SHOES/ ADJUSTING THE FRONT BRAKE CHASSIS EBS00079 CHECKING THE FRONT AND REAR BRAKE SHOES 1. Operate the brake. 2. Check: • wear indicator 1 Reaches the wear limit line 2 → Replace the brake shoes as a set. Refer to “FRONT AND REAR BRAKES” inchapter 7...

3 - 23 CHK ADJ ADJUSTING THE REAR BRAKE EBS00084 ADJUSTING THE REAR BRAKE NOTE: _ Before adjusting the rear brake, the rear brakelinings should be checked. CAUTION: _ Proper lever free play is essential to avoidexcessive brake drag. 1. Place the machine on a level surface.2. Measure: • rear brake le...

3 - 24 CHK ADJ CHECKING THE FINAL GEAR OIL LEVEL/ CHANGING THE FINAL GEAR OIL EBS00101 CHECKING THE FINAL GEAR OIL LEVEL 1. Place the machine on a level surface.2. Remove: • dipstick 1 3. Check: • final gear oil level Oil level should be between the maximum a and minimum b marks. Oil level low → Add...

3 - 25 CHK ADJ CHANGING THE FINAL GEAR OIL/ CHECKING THE SWINGARM DUST BOOT 6. Fill: • final gear case CAUTION: _ Take care not to allow foreign material toenter the final gear case. 7. Check: • final gear oil level Refer to “CHECKING THE FINAL GEAROIL LEVEL”. 8. Install: • dipstick Total amount 0.1...

3 - 26 CHK ADJ CHECKING THE STEERING SYSTEM EBS00107 CHECKING THE STEERING SYSTEM 1. Place the machine on a level surface.2. Check: • steering shaft bushings and bearings Move the handlebar up and down, and/orback and forth. Excessive play → Replace the steering shaft bushings and or bearings. Refer...

3 - 28 CHK ADJ ADJUSTING THE TOE-IN/CHECKING THE FRONT AND REAR SHOCK ABSORBERS ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Mark both tie-rods ends. This reference point will be needed duringadjustment. b. Loosen the locknuts (tie-rod end) 1 of both tie-rods. c. The same number of turns sho...

3 - 29 CHK ADJ CHECKING THE TIRES EBS00114 CHECKING THE TIRES WARNING _ This model is equipped with low pressuretires. It is important that they be inflatedcorrectly and maintained at the properpressures. • TIRE CHARACTERISTICS 1) Tire characteristics influence the han- dling of ATVs. The tires list...

3 - 31 CHK ADJ CHECKING THE TIRES/ CHECKING THE WHEELS 2. Check: • tire surfaces Wear/damage → Replace. WARNING _ It is dangerous to ride with a worn-out tire.When tire wear is out of specification,replace the tire immediately. Tire wear limit a Front and rear: 3 mm (0.12 in) EBS00116 CHECKING THE W...

3 - 32 CHK ADJ CHECKING AND LUBRICATING THE CABLES/LUBRICATING THE LEVERS, STEERING SHAFT AND STEERING KNUCKLES EBS00117 CHECKING AND LUBRICATING THE CABLES WARNING _ A damaged cable sheath may cause corro-sion and interfere with the cable move-ment. An unsafe condition may result soreplace a damage...

3 - 33 CHK ADJ CHECKING AND CHARGING THE BATTERY EBS00119 ELECTRICAL SYSTEM CHECKING AND CHARGING THE BATTERY WARNING _ Batteries generate explosive hydrogen gasand contain electrolyte which is made ofpoisonous and highly caustic sulfuric acid. Therefore, always follow these preventivemeasures: • We...

3 - 34 CHK ADJ CHECKING AND CHARGING THE BATTERY 3. Remove: • battery 4. Check: • electrolyte level The electrolyte level should be between theminimum level mark a and the maximum level mark b . Below the minimum level mark → Add dis- tilled water to the proper level. CAUTION: _ Add only distilled w...

3 - 35 CHK ADJ CHECKING AND CHARGING THE BATTERY • Do not use a high-rate battery charger. They force a high-amperage current intothe battery quickly and can cause batteryoverheating and battery plate damage. • If it is impossible to regulate the charging current on the battery charger, be carefulno...

3 - 36 CHK ADJ CHECKING AND CHARGING THE BATTERY 7. Check: • battery breather hose and battery vent Obstruction → Clean. Damage → Replace. 8. Install: • battery 9. Connect: • battery breather hose 1 CAUTION: _ When checking the battery, make sure thebattery breather hose is properly installedand rou...

3 - 37 CHK ADJ CHECKING THE FUSE EBS00121 CHECKING THE FUSE CAUTION: _ To avoid a short circuit, always set themain switch to “OFF” when checking orreplacing a fuse. 1. Remove: • seat Refer to “SEAT, FENDERS AND FUELTANK”. • fuse holder 1 2. Check: • fuse ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ...

3 - 38 CHK ADJ CHECKING THE FUSE d. If the fuse immediately blows again, check the electrical circuit. WARNING _ Never use a fuse with an amperage ratingother than that specified. Improvising orusing a fuse with the wrong amperage rat-ing may cause extensive damage to theelectrical system, cause the...

4 - 1 ENG EBS00198 ENGINE ENGINE EXHAUST PIPE/MUFFLER, BREATHER HOSE AND LEADS 1 3 4 5 2 T R . . 10 Nm (1.0 m • kg, 7.2 ft • Ib) T R . . 25 Nm (2.5 m • kg, 18 ft • Ib) Order Job/Part Q’ty Remarks Removing the exhaust pipe/muffler, breather hose and leads Remove the parts in the order listed. Rear fe...

4 - 2 ENG ENGINE EBS00205 ENGINE MOUNTING BOLTS 3 2 1 5 1 3 2 4 T R . . 33 Nm (3.3 m • kg, 24 ft • Ib) T R . . 33 Nm (3.3 m • kg, 24 ft • Ib) Order Job/Part Q’ty Remarks Removing the engine mounting bolts Remove the parts in the order listed. Carburetor Refer to “CARBURETOR” in chapter 5. Starter mo...

4 - 4 ENG ENGINE REMOVING THE ENGINE 1. Remove: • metal clamps NOTE: After removing the metal clamps, slide the dustboot 1 towards the swingarm. 1 EBS00207 INSTALLING THE ENGINE 1. Install: • dust boot 1 NOTE: Before mounting the engine assembly, installthe dust boot onto the middle driven gear bear...

4 - 5 ENG CYLINDER HEAD EBS00218 CYLINDER HEAD Order Job/Part Q’ty Remarks Removing the cylinder head Remove the parts in the order listed. Carburetor assembly Refer to “CARBURETOR” in chapter 5. Exhaust pipe/muffler Refer to “ENGINE”. C.D.I. magneto cover Refer to “C.D.I. MAGNETO”. 1 Spark plug lea...

4 - 7 ENG CYLINDER HEAD EBS00220 REMOVING THE CYLINDER HEAD 1. Align: • “T” mark on the rotor (with the stationary pointer on the crank-case) ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Turn the crankshaft counterclockwise with a wrench. b. Align the “T” mark 1 on the rotor with the station...

4 - 8 ENG CYLINDER HEAD 4. Remove: • bolts • nuts• cylinder head 1 NOTE: _ Working in a crisscross pattern, loosen eachnut 1/4 of a turn. 1 EBS00224 CHECKING THE CAMSHAFT SPROCKET 1. Check: • camshaft sprocket Wear/damage → Replace the camshaft sprocket and timing chain as a set. 1 1/4 of a tooth 2 ...

4 - 9 ENG CYLINDER HEAD EBS00230 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: • cylinder head Damage/scratches → Replace...

4 - 10 ENG CYLINDER HEAD EBS00233 INSTALLING THE CYLINDER HEAD 1. Install: • cylinder head 1 • nuts • bolts NOTE: _ Tighten the nuts in two stages and a crisscrosspattern. 2. Install: • camshaft sprocket ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Rotate the camshaft to align the camshaft g...

4 - 12 ENG CAMSHAFT, ROCKER ARMS AND VALVES EBS00235 CAMSHAFT, ROCKER ARMS AND VALVES Order Job/Part Q’ty Remarks Removing the camshaft, rocker arms and valves Remove the parts in the order listed. Cylinder head Refer to “CYLINDER HEAD”. 1 Intake manifold 1 2 Rocker arm shaft 2 Refer to “REMOVING TH...

4 - 13 ENG Order Job/Part Q’ty Remarks 13 Valve guide 2 For installation, reverse the removal pro-cedure. CAMSHAFT, ROCKER ARMS AND VALVES

4 - 14 ENG CAMSHAFT, ROCKER ARMS AND VALVES EBS00237 REMOVING THE ROCKER ARMS AND CAMSHAFT 1. Loosen: • locknuts • adjusters 2. Remove: • intake rocker arm shaft • exhaust rocker arm shaft • intake rocker arm • exhaust rocker arm NOTE: _ Remove the rocker arm shafts with the slidehammer bolt 1 and w...

4 - 15 ENG CAMSHAFT, ROCKER ARMS AND VALVES 2. Remove: • valve cotters NOTE: _ Attach a valve spring compressor 1 and attachment 2 between the valve spring retainer and the cylinder head to remove thevalve cotters. Valve spring compressor P/N. YM-04019, 90890-04019 Valve spring compressor attach-men...

4 - 16 ENG CAMSHAFT, ROCKER ARMS AND VALVES 2. Check: • rocker arm shaft Blue discoloration/excessive wear/pitting/scratches → Replace or check the lubrica- tion system. 3. Check: • camshaft lobe Excessive wear → Replace the camshaft. 4. Measure: • rocker arm inside diameter a Out of specification →...

4 - 17 ENG CAMSHAFT, ROCKER ARMS AND VALVES EBS00240 CHECKING THE VALVES AND VALVE SPRINGS 1. Measure: • stem-to-guide clearance Out of specification → Replace the valve guide. 2. Replace: • valve guide ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ NOTE: _ To ease guide removal, installation and...

4 - 18 ENG CAMSHAFT, ROCKER ARMS AND VALVES 3. Check: • valve face Pitting/wear → Grind the face. • valve stem end Mushroom shape or diameter larger thanthe body of the stem → Replace. 4. Measure: • margin thickness a Out of specification → Replace. Margin thickness Intake 0.5 ~ 0.9 mm (0.0197 ~ 0.0...

4 - 19 ENG CAMSHAFT, ROCKER ARMS AND VALVES 8. Measure: • valve seat width a Out of specification → Reface the valve seat. ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Apply Mechanic’s blueing dye (Dykem) b to the valve face. b. Install the valve into the cylinder head. c. Press the valve th...

4 - 20 ENG CAMSHAFT, ROCKER ARMS AND VALVES b. Apply molybdenum disulfide oil to the valve stem. c. Install the valve into the cylinder head. d. Turn the valve until the valve face and valve seat are evenly polished, then clean off allof the compound. NOTE: _ For best lapping results, lightly tap th...

4 - 21 ENG CAMSHAFT, ROCKER ARMS AND VALVES 12.Measure: • spring tilt a Out of specification → Replace. Spring tilt limit Inner 2.5°/1.4 mm (2.5°/0.06 in) EBS00241 INSTALLING THE VALVES AND VALVE SPRINGS 1. Apply: • molybdenum disulfide oil (onto the valve stem and valve stem seal) 2. Install: • val...

4 - 23 ENG CYLINDER AND PISTON EBS00245 CYLINDER AND PISTON Order Job/Part Q’ty Remarks Removing the cylinder and piston Remove the parts in the order listed. Cylinder head Refer to “CYLINDER HEAD”. 1 Cylinder 1 Refer to “INSTALLING THE CYLINDER”. 2 Cylinder gasket 1 3 Dowel pin 2 4 Piston pin clip ...

4 - 24 ENG CYLINDER AND PISTON EBS00247 REMOVING THE PISTON 1. Remove: • piston pin clips 1 • piston pin 2 • piston 3 NOTE: _ Before removing each piston pin, deburr theclip groove and pin hole area. If the piston pingroove is deburred and the piston pin is stilldifficult to remove, use the piston p...

4 - 27 ENG CYLINDER AND PISTON EBS00251 CHECKING THE PISTON PIN 1. Check: • piston pin Blue discoloration/grooves → Replace the piston pin and then check the lubricationsystem. 2. Measure: • piston pin outside diameter a Out of specification → Replace the piston pin. Piston pin outside diameter 12.9...

4 - 28 ENG CYLINDER AND PISTON EBS00252 INSTALLING THE PISTON 1. Install: • piston rings (onto the piston) NOTE: _ • Be sure to install the piston rings so that the manufacturer’s marks or numbers arelocated on the upper side of the rings. • Lubricate the piston and piston rings liberally with engin...

4 - 29 ENG EBS00253 INSTALLING THE CYLINDER 1. Install: • cylinder NOTE: _ Install the cylinder with one hand while com-pressing the piston rings with the other hand. CAUTION: _ • Be careful not to damage the timing chain damper during installation. • Pass the timing chain through the timing chain c...

4 - 31 ENG C.D.I. MAGNETO EBS00259 REMOVING THE C.D.I. MAGNETO ROTOR 1. Remove: • C.D.I. magneto rotor nut • washer NOTE: _ • While holding the C.D.I. magneto rotor 1 with the sheave holder 2 , loosen the rotor nut. • Do not allow the sheave holder to touch the projection on the rotor. Sheave holder...

4 - 33 ENG CLUTCH EBS00291 CLUTCH Order Job/Part Q’ty Remarks Removing the clutch Remove the parts in the order listed. Engine oil Drain.Refer to “CHANGING THE ENGINE OIL” in chapter 3. C.D.I. magneto cover Refer to “C.D.I. MAGNETO”. 1 Clutch cover 1 Refer to “REMOVING THE CLUTCH” and “INSTALLING TH...

4 - 35 ENG CLUTCH EBS00297 REMOVING THE CLUTCH 1. Remove: • clutch cover NOTE: _ Loosen each screw 1/4 of a turn at a time, instages and in a crisscross pattern. After all ofthe screws are fully loosened, remove them. 2. Loosen: • clutch boss nut 1 NOTE: _ While holding the clutch boss 2 with the cl...

4 - 36 ENG CLUTCH EBS00301 CHECKING THE CLUTCH PLATES The following procedure applies to all of theclutch plates.1. Check: • clutch plate Damage → Replace the clutch plates as a set. 2. Measure: • clutch plate warpage (with a surface plate and thickness gauge 1 ) Out of specification → Replace the c...

4 - 37 ENG CLUTCH EBS00304 CHECKING THE CLUTCH BOSS 1. Check: • clutch boss splines • clutch boss cam groove• clutch boss one-way cam Damage/pitting/wear → Replace the clutch boss and clutch boss one-way cam as aset. NOTE: _ Pitting on the clutch boss splines will causeerratic clutch operation. EBS0...

4 - 38 ENG CLUTCH EBS00310 INSTALLING THE PRIMARY DRIVE GEAR 1. Tighten: • primary drive gear nut 1 NOTE: _ Place an aluminum plate 2 between the teeth of the primary driven gear/clutch housing 3 and primary drive gear 4 . Sheave holder P/N. YS-01880-A, 90890-01701 1 4 2 3 T R . . 50 Nm (5.0 m · kg,...

4 - 39 ENG 3. Install: • friction plate 2 1 • clutch plates 2 2 • friction plates 1 (with black color marking) 3 • clutch plate 1 4 5 thrust weight plate a silver section NOTE: Install the clutch plates and friction plates alter-nately on the clutch boss, starting and endingwith a friction plate. CA...

4 - 40 ENG 5. Install: • clutch housing 1 NOTE: _ Make sure that the primary driven gear teethand primary drive gear teeth mesh correctly. 1 6. Install: • clutch boss one-way cam 1 • clutch boss 2 NOTE: Align section a of the clutch boss one-way cam with section b of the clutch boss and then install...

4 - 42 ENG STARTER CLUTCH AND OIL PUMP EBS00315 STARTER CLUTCH AND OIL PUMP Order Job/Part Q’ty Remarks Removing the starter clutch and oil pump Remove the parts in the order listed. Clutch assembly Refer to “CLUTCH”. 1 Starter idle gear assembly 1 2 Starter wheel gear 1 3 Starter clutch assembly 1 ...

4 - 43 ENG STARTER CLUTCH AND OIL PUMP EBS00316 E 5 4 3 2 1 Order Job/Part Q’ty Remarks Disassembling the oil pump Remove the parts in the order listed. 1 Oil pump housing cover 1 2 Oil pump shaft 1 3 Inner rotor 1 4 Outer rotor 1 5 Oil pump housing 1 For assembly, reverse the disassemblyprocedure.

4 - 44 ENG STARTER CLUTCH AND OIL PUMP EBS00263 CHECKING THE STARTER CLUTCH 1. Check: • starter clutch rollers 1 Cracks/damage → Replace. 2. Check: • starter clutch screws 1 Loose → Replace with a new one, and clinch the end of the screw. NOTE: Lock the threads on the starter clutch screwsby staking...

4 - 45 ENG STARTER CLUTCH AND OIL PUMP 4. Check: • starter idle gear teeth 1 • starter wheel gear teeth 2 Burrs/clips/roughness/wear → Replace. 5. Check: • starter wheel gear contacting surface a Damage/pitting/wear → Replace. a 2 1 EBS00330 CHECKING THE OIL PUMP 1. Check: • oil pump drive gear 1 • ...

4 - 46 ENG STARTER CLUTCH AND OIL PUMP 3. Measure: • inner-rotor-to-outer-rotor-tip clearance a • outer-rotor-to-oil-pump-housing clearance b • oil-pump-housing-to-inner-rotor-and-outer- rotor clearance c Out of specification → Replace the oil pump. 1 Inner rotor 2 Outer rotor 3 Oil pump housing Inn...

4 - 47 ENG SHIFT SHAFT Order Job/Part Q’ty Remarks Removing the shift shaft Remove the parts in the order listed. Clutch assembly Refer to “CLUTCH”. 1 Shift shaft 1 2 Stopper lever 1 3 Dowel pin 5 For installation, reverse the removal pro-cedure. SHIFT SHAFT

4 - 48 ENG EBS01018 CHECKING THE SHIFT SHAFT 1. Check: • shift shaft 1 Bends/damage/wear → Replace. • shift shaft spring 2 Damage/wear → Replace. EBS01019 CHECKING THE STOPPER LEVER 1. Check: • stopper lever 1 • stopper lever spring 2 Bends/damage → Replace. Roller turns roughly → Replace the stoppe...

4 - 49 ENG CRANKCASE EBS00319 CRANKCASE Order Job/Part Q’ty Remarks Removing the timing chain and sep-arating the crankcase Remove the parts in the order listed. Engine Refer to “ENGINE”. Cylinder head Refer to “CYLINDER HEAD”. Cylinder and piston Refer to “CYLINDER AND PISTON”. C.D.I. magneto Refer...

4 - 50 ENG CRANKCASE EBS00321 CRANKCASE BEARINGS E 1 2 2 LT E 2 2 2 E E 2 T R . . 8 Nm (0.8 m • kg, 5.8 ft • Ib) Order Job/Part Q’ty Remarks Removing the crankcase bearings Remove the parts in the order listed. Crankshaft Refer to “CRANKSHAFT”. Transmission Refer to “TRANSMISSION”. Middle driven pin...

4 - 51 ENG CRANKCASE EBS00333 SEPARATING THE CRANKCASE 1. Separate: • right crankcase • left crankcase ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Remove the crankcase screws. NOTE: _ • Loosen each screw 1/4 of a turn at a time and after all the screws are loosened,remove them. • Loosen the...

4 - 52 ENG CRANKCASE EBS00339 CHECKING THE BEARINGS AND OIL SEALS 1. Check: • bearings Clean and lubricate, then rotate the innerrace with a finger. Roughness → Replace. 2. Check: • oil seals Damage/wear → Replace. EBS00338 CHECKING THE CRANKCASE 1. Thoroughly wash the case halves in a mild solvent....

4 - 53 ENG CRANKCASE EBS00341 ASSEMBLING THE CRANKCASE 1. Apply: • sealant (Quick Gasket ® ) or Yamaha bond No. 1215 1 (to the mating surfaces of both case halves) 2. Install: • dowel pin 3. Fit the right crankcase onto the left case. Tap lightly on the case with a soft hammer. CAUTION: _ Before ins...

4 - 54 ENG EBS00326 CRANKSHAFT Order Job/Part Q’ty Remarks Removing the crankshaft Remove the parts in the order listed. Crankcase Separate.Refer to “CRANKCASE”. 1 Crankshaft 1 Refer to “INSTALLING THE CRANK-SHAFT”.For installation, reverse the removal pro-cedure. CRANKSHAFT

4 - 56 ENG TRANSMISSION EBS00345 TRANSMISSION Order Job/Part Q’ty Remarks Removing the transmission Remove the parts in the order listed. Crankcase Separate.Refer to “CRANKCASE”. 1 Main axle/1st pinion gear 1 2 Shift fork guide bar 1 Refer to “REMOVING THE TRANSMIS-SION” and “INSTALLING THE TRANS-MI...

4 - 57 ENG REMOVING THE TRANSMISSION 1. Remove: • shift fork guide bar 1 • shift fork 2 • drive axle/middle drive pinion gear assem- bly 3 • shift drum 4 NOTE: Remove the shift fork guide bar, shift fork,drive axle/middle drive gear assembly, andshift drum from the crankcase together. 4 1 2 3 EBS003...

4 - 58 ENG TRANSMISSION EBS01103 CHECKING THE SHIFT DRUM 1. Check: • shift drum grooves Damage/scratches/wear → Replace the shift drum assembly. • shift drum segment 1 Damage/wear → Replace the shift drum assembly. EBS00354 CHECKING THE TRANSMISSION 1. Measure: • main axle runout (with a centering d...

4 - 59 ENG TRANSMISSION EBS00357 INSTALLING THE TRANSMISSION 1. Install: • shift drum 1 • drive axle/middle drive pinion gear assem- bly 2 • shift fork 3 • shift fork guide bar 4 NOTE: _ • The embossed marks on the shift fork should face towards the left of the engine. • Be sure to install the forke...

4 - 60 ENG MIDDLE GEAR EBS00363 MIDDLE GEAR Order Job/Part Q’ty Remarks Removing the middle gear Remove the parts in the order listed. Crankcase Separate.Refer to “CRANKCASE”. Drive axle/middle drive pinion gear assembly Refer to “TRANSMISSION”. 1 Middle drive gear shim 1 2 Middle driven gear shim R...

4 - 61 ENG MIDDLE GEAR EBS00366 REMOVING THE MIDDLE DRIVEN SHAFT 1. Remove: • universal joint ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Remove the circlips. b. Place the universal joint in a press. c. With a suitable diameter pipe 1 beneath the yoke 2 , press the bearings 3 into the pipe ...

4 - 62 ENG MIDDLE GEAR 3. Remove: • bearing housing assembly 1 ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Clean the outside of the middle driven shaft. b. Place the middle driven shaft onto a hydrau- lic press. CAUTION: _ • Never directly press the shaft end with a hydraulic press, this wi...

4 - 63 ENG MIDDLE GEAR 2. Check: • O-ring Damage → Replace. • bearings Pitting/damage → Replace. 3. Check: • universal joint movement Roughness → Replace universal joint. EBS00370 SELECTING MIDDLE DRIVEN GEAR SHIMS When the drive and driven gear, bearing hous-ing assembly and/or crankcase replaced, ...

4 - 64 ENG MIDDLE GEAR EBS00373 INSTALLING THE MIDDLE DRIVEN SHAFT 1. Install: • bearing retainer ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Secure the bearing housing edge in the vise with a clean rag 1 . NOTE: Apply locking agent (LOCTITE ® ) to the threads of bearing retainer. b. Attach...

4 - 65 ENG MIDDLE GEAR 3. Install: • universal joint ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Install the yoke into the universal joint. b. Apply wheel bearing grease to the bearings. c. Install the bearing 1 onto the yoke. CAUTION: _ Check each bearing. The needles can eas-ily fall out ...

4 - 66 ENG EBS00376 MEASURING THE MIDDLE GEAR BACKLASH 1. Measure: • middle gear lash ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Temporarily install the drive axle/middle drive pinion gear assembly and middledriven pinion gear. b. Attach the pinion gear fix clamp 1 to the drive axle/middle...

5 - 1 CARB EBS00141 CARBURETOR CARBURETOR 4 8 9 7 6 5 1 2 T R . . 7 Nm (0.7 m • kg, 5.1 ft • Ib) 3 (3) Order Job/Part Q’ty Remarks Removing the carburetor Remove the parts in the order listed. 1 Fuel overflow hose 1 2 Carburetor air vent hose 1 3 Fuel hose 1 4 Carburetor assembly 1 5 Carburetor top ...

5 - 2 CARB CARBURETOR EBS00144 Order Job/Part Q’ty Remarks Disassembling the carburetor Remove the parts in the order listed. NOTE: _ Before disassembling the carburetor,make sure to note the number of timesthe pilot screw is turned out from theseated position to its set position. 1 Throttle stop sc...

5 - 4 CARB CARBURETOR EBS00146 DISASSEMBLING THE CARBURETOR NOTE: _ Before disassembling the carburetor, makesure to note the number of times the pilotscrew is turned out from the seated position toits set position. EBS00148 CHECKING THE CARBURETOR 1. Check: • carburetor body • float chamber Cracks/...

5 - 6 CARB CARBURETOR EBS00150 ASSEMBLING THE CARBURETOR NOTE: _ Before assembling the carburetor, make sureto turn out the pilot air screw the same numberof times, as noted before disassembly, fromthe seated position to the set position. CAUTION: _ • Before reassembling, wash all of the parts in a ...

5 - 7 CARB CARBURETOR EBS00154 MEASURING AND ADJUSTING THE FUEL LEVEL 1. Measure: • fuel level a Out of specification → Adjust. ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Stand the machine on a level surface. b. Install the fuel level gauge 1 onto the fuel drain pipe 2 . c. Loosen the fuel...

6 - 1 DRIV EBS00155 DRIVE TRAIN TROUBLESHOOTING The following conditions may indicate damaged shaft drive components: NOTE: _ Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite subtle anddifficult to distinguish from normal machine operating noise. If there is rea...

6 - 2 DRIV TROUBLESHOOTING EBS00156 CHECKING NOISES 1. Investigate any unusual noises. ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. A “rolling rumble” noise during coasting, acceleration, or deceleration. The noiseincreases with rear wheel speed, but it doesnot increase with higher engine or...

6 - 4 DRIV TROUBLESHOOTING EBS00157 TROUBLESHOOTING CHART When basic condition “a” and “b” exist, check the following points: Check the wheel and hub nuts for tightness. NO Torque to specification. (Refer to “FRONT AND REAR WHEELS” inchapter 7.) YES Check the rear brake adjustment. NO Adjust per ins...

6 - 5 DRIV REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT EBS00178 REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT Order Job/Part Q’ty Remarks Removing the rear axle/final drive assembly and drive shaft Remove the parts in the order listed. Rear wheels Refer to “FRONT AND REAR WHEELS” in chapter 7. B...

6 - 7 DRIV REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT EBS00179 REAR AXLE/FINAL DRIVE ASSEMBLY Order Job/Part Q’ty Remarks Disassembling the rear axle/final drive assembly Remove the parts in the order listed. 1 Rear axle housing 1 2 Rear axle housing bearing retainer 1 Refer to “DISASSEMBLING TH...

6 - 8 DRIV REMOVING THE NUTS 1. Place the machine on a level surface. 2. Loosen: • nuts 1 NOTE: _ • Apply the rear brake lever so that the rear axle does not turn, when loosening the nuts. • Use an axle nut wrench (36 mm). 3. Elevate the rear wheels by placing the suit- able stand under the frame. 4...

6 - 9 DRIV REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT EBS00181 DISASSEMBLING THE REAR AXLE HOUSING 1. Remove: • rear axle housing bearing retainer NOTE: _ Use a ring nut wrench 1 . Ring nut wrench P/N. YM-38404, 90890-01430 EBS00181 DISASSEMBLING THE FINAL GEAR CASE 1. Remove: • rear axle (with ...

6 - 10 DRIV REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT EBS00190 CHECKING THE REAR AXLE 1. Check: • rear axle runout a Out of specification → Replace. WARNING _ Do not attempt to straighten a bent axle. Rear axle runout limit 1.5 mm (0.06 in) EBS00191 CHECKING THE DRIVE SHAFT 1. Check: • drive sh...

6 - 12 DRIV REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT EBS00196 INSTALLING THE REAR AXLE/FINAL DRIVE ASSEMBLY 1. Lubricate: • drive shaft • coupling gear • O-ring • oil seal • bearing 2. Install: • drive shaft • coupling gear (to the universal joint) 3. Install: • rear axle/final drive assembly ...

6 - 13 DRIV REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT EBS00397 INSTALLING THE NUTS 1. Tighten: • nuts 1 , 2 ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Check if the rear brake assembly is installed on the rear axle housing. If the rear brakeassembly is not installed, refer to “FRONTAND...

7 - 1 CHAS EBS00378 CHASSIS FRONT AND REAR WHEELS FRONT WHEELS Order Job/Part Q’ty Remarks Removing the front wheels Remove the parts in the order listed.Place the machine on a level surface. WARNING _ Securely support the machine so thereis no danger of it falling over. The following procedure appl...

7 - 2 CHAS EBS00379 REAR WHEELS 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 thereis no danger of it falling over. The following procedure applies to bothof the rear wheels. 1...

7 - 4 CHAS FRONT AND REAR WHEELS WARNING _ Eye protection is recommended whenusing striking tools. c. To install the wheel bearings, reverse the above sequence. Use a socket thatmatches outside diameter of bearing outerrace to drive in bearing. CAUTION: _ Do not strike the center race or balls of th...

7 - 5 CHAS FRONT AND REAR WHEELS EBS00391 INSTALLING THE WHEELS The following procedure applies to both of thefront and rear wheels.1. Install: • wheel NOTE: _ The arrow mark 1 on the tire must point in the direction of rotation + of the wheel. È Front wheel É Rear wheel 2. Tighten: • nuts È É T R ....

7 - 6 CHAS FRONT AND REAR BRAKES EBS00437 FRONT AND REAR BRAKES FRONT BRAKE Order Job/Part Q’ty Remarks Removing the front brakes Remove the parts in the order listed. Front wheels Refer to “FRONT AND REAR WHEELS”.The following procedure applies to bothof the front brakes. 1 Brake shoe 2 Refer to “I...

7 - 7 CHAS FRONT AND REAR BRAKES REAR BRAKE Order Job/Part Q’ty Remarks Removing the rear brake Remove the parts in the order listed.Refer to “FRONT AND REAR WHEELS”. 1 Brake drum cover 1 2 Nut 1 Refer to “REAR AXLE/FINAL DRIVE ASSEMBLY AND DRIVE SHAFT” in chapter 6. 3 Nut 1 4 Lock washer 2 Refer to...

7 - 9 CHAS FRONT AND REAR BRAKES REMOVING THE BRAKES The following procedure applies to each brake.1. Remove: • brake camshaft lever• brake shoe wear indicator• brake camshaft NOTE: When removing the brake camshaft lever,mark the position on the brake camshaft leverwhere it is aligned with the punch...

7 - 10 CHAS FRONT AND REAR BRAKES 2. Check: • brake shoe lining surface Glazed areas → Remove. Use coarse sandpaper. NOTE: _ After using sandpaper, wipe off the polishedparticles with a cloth. 3. Measure: • brake shoe lining thickness a Out of specification → Replace. 1 Measuring points NOTE: _ Repl...

7 - 11 CHAS FRONT AND REAR BRAKES 2. Check: • brake drum inner surface Oil/scratches → Remove. È Front brake drum É Rear brake drum EBS00442 INSTALLING THE FRONT BRAKES The following procedure applies to both of thefront brakes.Reverse the “Removal” procedure. Note the following points.1. Lubricate:...

7 - 12 CHAS 3. Install: • brake shoe plate 1 NOTE: _ When installing the brake shoe plate, align thegroove a of the brake shoe plate with the pro- jection b of the steering knuckle. 4. Install: • front brake cable (drum side)• brake shoes NOTE: Check that the brake shoes are properly posi-tioned. 5....

7 - 14 CHAS STEERING SYSTEM EBS00444 STEERING SYSTEM HANDLEBAR Order Job/Part Q’ty Remarks Removing the handlebar Remove the parts in the order listed. Handlebar cover Refer to “SEAT, FENDERS AND FUEL TANK” in chapter 3. 1 Handlebar grip 2 Refer to “REMOVING THE HANDLEBAR GRIPS” and “INSTALLING THE ...

7 - 16 CHAS STEERING SYSTEM EBS00447 REMOVING THE HANDLEBAR GRIPS 1. Remove: • handlebar grips 1 NOTE: _ Blow compressed air between the handlebarand handlebar grip, and gradually push thegrip off the handlebar. EBS00445 REMOVING THE REAR BRAKE SWITCH 1. Remove: • rear brake switch 1 NOTE: _ Push th...

7 - 17 CHAS STEERING SYSTEM EBS00449 INSTALLING THE HANDLEBAR 1. Install: • lower handlebar holder• handlebar • upper handlebar holders NOTE: _ • Install the handlebar within 15° from the hori- zontal line shown in the illustration. • The upper handlebar holders should be installed with the punched ...

7 - 18 CHAS STEERING SYSTEM EBS00451 INSTALLING THE REAR BRAKE LEVER 1. Install: • rear brake lever 1 • handlebar switch 2 NOTE: _ • Install the rear brake lever within 10° from the horizontal line shown in the illustration. • After installing the rear brake lever, make sure the rear brake lever 1 ,...

7 - 19 CHAS STEERING SYSTEM EBS00454 STEERING STEM 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” in chapter 3. Handlebar Refer to “HANDLEBAR”. 1 Lock washer 1 Refer to “INSTALLING THE LOCK WASHER”. 2 S...

7 - 20 CHAS STEERING SYSTEM EBS00455 REMOVING THE STEERING STEM 1. Remove: • steering stem NOTE: When loosening each tie-rod end nut 1 , hold the tie-rod ball joint with a 14-mm wrench 2 . EBS00456 CHECKING THE STEERING STEM 1. Check: • steering stem Bends → Replace. WARNING _ Do not attempt to stra...

7 - 21 CHAS STEERING SYSTEM EBS00460 TIE-RODS AND STEERING KNUCKLES Order Job/Part Q’ty Remarks Removing the tie-rods and steering knuckles Remove the parts in the order listed. Front brakes Refer to “FRONT AND REAR BRAKES”.The following procedure applies to bothof the tie-rods and steering knuckles...

7 - 22 CHAS STEERING SYSTEM EBS00461 REMOVING THE TIE-RODS The following procedure applies to both of thetie-rods.1. Remove: • tie-rod 1 NOTE: _ When removing the tie-rod, hold each tie-rodball joint with a 14-mm wrench 2 and then loosen the tie-rod end nut. EBS00462 CHECKING THE TIE-RODS The follow...

7 - 23 CHAS EBS00465 INSTALLING THE TIE-RODS The following procedure applies to both of thetie-rods.1. Install: • tie-rod NOTE: _ • The tie-rod side which must be installed on the inside has grooves 1 . • When installing the tie-rod, hold each tie-rod ball joint with a 14-mm wrench 2 and then tighte...

7 - 24 CHAS FRONT SHOCK ABSORBER ASSEMBLIES AND FRONT SWINGARM EBS00468 FRONT SHOCK ABSORBER ASSEMBLIES AND FRONT SWINGARM Order Job/Part Q’ty Remarks Removing the front shock absorber assemblies and front swingarm Remove the parts in the order listed. Steering knuckles Refer to “STEERING SYSTEM”. 1...

7 - 25 CHAS FRONT SHOCK ABSORBER ASSEMBLIES AND FRONT SWINGARM EBS00469 REMOVING THE FRONT SWINGARM 1. Check: • front swingarm free play ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Check the front swingarm side play È by moving it from side to side. If side play is noticeable, check the bus...

7 - 26 CHAS REAR SHOCK ABSORBER AND REAR SWINGARM EBS00476 REAR SHOCK ABSORBER AND REAR SWINGARM Order Job/Part Q’ty Remarks Removing the rear shock absorber and swingarm Remove the parts in the order listed. C.D.I. magneto cover Refer to “C.D.I. MAGNETO” in chapter 4. Rear axle/final drive assembly...

7 - 27 CHAS REAR SHOCK ABSORBER AND REAR SWINGARM EBS00477 REMOVING THE REAR SWINGARM 1. Check: • swingarm free play ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼ a. Check the tightening torque of the pivot shaft. b. Check the rear swingarm side play È by moving it from side to side. If side pla...

7 - 28 CHAS REAR SHOCK ABSORBER AND REAR SWINGARM EBS00479 CHECKING THE REAR SWINGARM 1. Check: • rear swingarm Bends/cracks/damage → Replace. 2. Check: • bushings Wear/damage → Replace. EBS00481 CHECKING THE DUST BOOT 1. Check: • dust boot 1 Damage → Replace. INSTALLING THE LOCK WASHER 1. Install: ...

8 - 1 – + ELEC EBS00500 ELECTRICAL ELECTRICAL COMPONENTS 1 Main switch 2 Neutral indicator light 3 Rear brake switch 4 Handlebar switch 5 Battery 6 Main fuse 7 Engine stop switch (frame) 8 Rectifier/regulator 9 Diode 0 Starting circuit cut-off relay A Starter relay B Neutral switch C Pickup coil/sta...

8 - 2 – + ELEC CHECKING SWITCH CONTINUITY EBS01028 CHECKING SWITCH CONTINUITY Check each switch for continuity with thepocket 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-pl...

8 - 3 – + 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 con...

8 - 4 – + ELEC CHECKING THE BULBS AND BULB SOCKETS EBS01030 CHECKING THE BULBS AND BULB SOCKETS Check each bulb and bulb socket for damageor wear, proper connections, and also for con-tinuity between the terminals. Damage/wear → Repair or replace the bulb, bulb socket or both. Improperly connected →...

8 - 6 – + ELEC CHECKING THE BULBS AND BULB SOCKETS CHECKING THE CONDITION OF THE BULB SOCKETS The following procedure applies to all of thebulb sockets. 1. Check: • bulb socket (for continuity) (with the pocket tester) No continuity → Replace. NOTE: _ Check each bulb socket for continuity in thesame...

8 - 7 – + ELEC IGNITION SYSTEM EBS00503 IGNITION SYSTEM CIRCUIT DIAGRAM (GRAY) (BLACK) (BLACK) (BLACK) W / R Y / R W Sb Sb B Sb Y / R B W R G / W B / R B / W B W / L W / R G / W B / R B O O Sb G / Y B / W Sb G / Y G / W W / L (BLACK) (BLACK) Br B / W B ON OFF OFF ON RUN OFF B / R W / R W / L G / W (...

8 - 8 – + ELEC IGNITION SYSTEM EBS01045 TROUBLESHOOTING Check: 1. spark plug2. ignition spark gap 3. spark plug cap resistance 4. ignition coil resistance 5. main switch 6. engine stop switches7. pickup coil resistance 8. source coil resistance 9. wiring connections (of the entire ignition system) N...

8 - 9 – + ELEC IGNITION SYSTEM EBS01034 NO YES EBS01036 YES NO 2. Ignition spark gap • Disconnect the spark plug cap from the spark plug. • Connect the ignition dynamic spark tester 1 as shown. 2 Spark plug cap 3 Spark plug • Set the main switch to “ON”. • Measure the ignition spark gap a . • Crank ...

8 - 12 – + ELEC ELECTRIC STARTING SYSTEM EBS00506 ELECTRIC STARTING SYSTEM CIRCUIT DIAGRAM (GRAY) (BLACK) (BLACK) (BLACK) W / R Y / R W Sb Sb B Sb Y / R B W R G / W B / R B / W B W / L W / R G / W B / R B O O Sb G / Y B / W Sb G / Y G / W W / L (BLACK) (BLACK) Br B / W B ON OFF OFF ON RUN OFF B / R ...

8 - 13 – + ELEC ELECTRIC STARTING SYSTEM EBS00507 STARTING CIRCUIT OPERATION The starting circuit on this model consists ofthe starter motor, starter relay, starting circuitcut-off relay, rear brake switch and neutralswitch. If the main switch is on and the enginestop switch is in the RUN position, ...

8 - 17 – + ELEC ELECTRIC STARTING SYSTEM EBS01060 YES NO EBS01059 YES NO 10.Diode • Remove the diode from the coupler. • Connect the pocket tester ( Ω × 1) to the diode terminals as shown. • Check the diode for continuity as follows. Positive tester probe → green/yellow 1 Negative tester probe → bla...

8 - 18 – + ELEC STARTER MOTOR EBS01061 STARTER MOTOR Order Job/Part Q’ty Remarks Removing the starter motor Remove the parts in the order listed. 1 Starter motor lead 1 2 Ground lead 1 3 Starter motor 1 For installation, reverse the removal pro-cedure. Disassembling the starter motor Remove the part...

8 - 20 – + ELEC STARTER MOTOR 5. Measure: • brush length a Out of specification → Replace the brushes as a set. 6. Measure: • brush spring force Out of specification → Replace the brush springs as a set. 7. Check: • gear teeth Damage/wear → Replace the gear. 8. Check: • bearing • oil seal • O-rings ...

8 - 21 – + ELEC CHARGING SYSTEM EBS00516 CHARGING SYSTEM CIRCUIT DIAGRAM (GRAY) (BL (BLACK) (BLACK) W / R Y / R W Sb Sb B Sb Y / R B W R G / W B / R B / W B W / L W / R G / W B / R Br B / W B ON OFF OFF ON RUN OFF B / R W / R W / L G / W (GRAY) G / W W / L W / R B / R W Y / R B Sb B Y R W Sb B Y / R...

8 - 23 – + ELEC CHARGING SYSTEM EBS01066 NO YES EBS01100 YES NO EBS01059 YES NO 3. Charging voltage • Connect the engine tachometer to the spark plug lead. • Connect the pocket tester (DC 20 V) to the battery as shown. Positive tester probe → positive battery terminal Negative tester probe → negativ...

8 - 24 – + ELEC SIGNAL SYSTEM EBS00521 SIGNAL SYSTEM CIRCUIT DIAGRAM (GRAY) (BLACK) (BLACK) (BLACK) W / R Y / R W Sb Sb B Sb Y / R B W R G / W B / R B / W B W / L W / R G / W B / R S G / Y B / W (BLACK) (B Br B / W B ON OFF OFF ON RUN OFF B / R W / R W / L G / W (GRAY) G / W W / L W / R B / R W Y / ...

8 - 26 – + ELEC SIGNAL SYSTEM EBS01075 CHECKING THE SIGNALING SYSTEM EBS01077 1. The neutral indicator light fails to come on. YES NO YES NO YES NO 1. Neutral indicator light bulb and socket • Check the neutral indicator light bulb and socket for continuity. Refer to “CHECKING THE BULBS ANDBULB SOCK...

9 - 1 TRBL 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. STARTING FAILUR...

9 - 2 TRBL SHTG STARTING FAILURE/HARD STARTING/POOR IDLE SPEED PERFORMANCE/POOR MEDIUM AND HIGH-SPEED PERFORMANCE COMPRESSION SYSTEMCylinder and cylinder head • Loose spark plug • Loose cylinder head or cylinder • Broken cylinder head gasket • Broken cylinder gasket • Worn, damaged or seized cylinde...

9 - 3 TRBL SHTG FAULTY DRIVE TRAIN EBS00540 FAULTY DRIVE TRAIN The following conditions may indicate damaged shaft drive components: NOTE: _ Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite subtle anddifficult to distinguish from normal machine operating noise. ...

9 - 4 TRBL SHTG FAULTY GEAR SHIFTING/CLUTCH SLIPPING/ DRAGGING/OVERHEATING EBS00541 FAULTY GEAR SHIFTING HARD SHIFTING Refer to “CLUTCH SLIPPING/DRAGGING—CLUTCH DRAGGING”. SHIFT LEVER DOES NOT MOVEShift shaft • Bent shift shaft Shift cam, shift forks • Groove jammed with impurities • Seized shift fo...

9 - 5 TRBL SHTG FAULTY BRAKE/SHOCK ABSORBER MALFUNCTION/ UNSTABLE HANDLING EBS00549 FAULTY BRAKE POOR BRAKING EFFECTFront and rear drum brake • Worn brake shoe lining • Worn brake drum • Oily or greasy brake shoe lining • Oily or greasy brake drum • Improperly adjusted brake lever free play • Improp...

YFM50S WIRING DIAGRAM (GRAY) (BLACK) (BLACK) (BLACK) W / R Y / R W Sb Sb B Sb Y / R B W R G / W B / R B / W B W / L W / R G / W B / R B O O Sb G / Y B / W Sb G / Y G / W W / L (BLACK) (BLACK) Br B / W B ON OFF OFF ON RUN OFF B / R W / R W / L G / W (GRAY) G / W W / L W / R B / R W Y / R B Sb B Y R W...