Table Of Contents - Yamaha YZ250 Owner's Service Manual

Table of Contents

Safety Information6
F.i.m. Machine Weights6
How To Read Descriptions8
Illustrated Symbols8
Table Of Contents9
Contents10
General Information10
Description11
Machine Identification12
Vehicle Identification Number12
Engine Serial Number12
Detachable Sidestand12
Checking Of Connection13
Gaskets, Oil Seals And O-Rings13
Lock Washers/Plates And Cotter Pins13
Bearings And Oil Seals13
Special Tools14
Control Functions17
Engine Stop Switch17
Clutch Lever17
Shift Pedal17
Starting And Break-In18
Air Filter Maintenance18
Starting A Cold Engine18
Break-In Procedures18
Torque-Check Points19
Cleaning And Storage20
General Specifications21
Maintenance Specifications22
Tightening Torques27
General Torque Specifications32
Definition Of Units32
Cable Routing Diagram34
Maintenance Intervals41
Regular Inspection And Adjustments41
Pre-Operation Inspection And Maintenance44
General Inspection And Maintenance44
Engine45
Checking The Coolant Level45
Changing The Coolant45
Checking The Radiator Cap45
Checking The Radiator Cap Opening Pressure45
Checking The Cooling System46
Adjusting The Clutch Cable Free Play46
Adjusting The Throttle Cable Free Play46
Lubricating The Throttle46
Cleaning The Air Filter Element47
Checking The Transmission Oil Level47
Chassis48
Changing The Transmission Oil48
Adjusting The Pilot Air Screw48
Adjusting The Engine Idling Speed48
Checking The Exhaust Pipe48
Adjusting The Front Brake49
Adjusting The Rear Brake49
Checking And Replacing The Front Brake Pads49
Checking And Replacing The Rear Brake Pads50
Checking The Rear Brake Pad Insulator51
Checking The Brake Fluid Level51
Checking The Sprocket51
Checking The Drive Chain51
Specifications51
Adjusting The Drive Chain Slack52
Checking The Front Fork52
Cleaning The Front Fork Oil Seal And Dust Seal52
Relieving The Front Fork Internal Pressure52
Adjustments52
Adjusting The Front Fork Rebound Damping Force53
Adjusting The Front Fork Compression Damping Force53
Checking The Rear Shock Absorber53
Adjusting The Rear Shock Absorber Spring Preload53
Adjusting The Rear Shock Absorber Rebound Damping Force54
Adjusting The Rear Shock Absorber Low Compression Damping Force54
Adjusting The Rear Shock Absorber High Compression Damping Force55
Checking The Tire Pressure55
Checking And Tightening The Spokes55
Checking The Wheels55
Lubrication57
Electrical58
Checking The Spark Plug58
Checking The Ignition Timing58
Seat, Fuel Tank And Side Covers59
Removing The Seat, Fuel Tank And Side Covers59
Removing The Side Cover60
Removing The Number Plate60
Removing The Exhaust Pipe And Silencer61
Changing The Silencer Fiber62
Removing The Radiator63
Checking The Radiator64
Installing The Radiator64
Removing The Carburetor And Reed Valve65
Disassembling The Carburetor66
Removing The Throttle Valve67
Removing The Pilot Air Screw67
Checking The Carburetor67
Checking The Needle Valve67
Measuring And Adjusting The Float Height68
Checking The Float68
Checking The Reed Valve68
Installing The Reed Valve68
Installing The Carburetor70
Removing The Cylinder Head And Cylinder71
Cylinder Head, Cylin Der And Piston71
Removing The Piston And Power Valve72
Removing The Push Rod73
Removing The Piston And Piston Ring73
Checking The Cylinder Head73
Checking The Cylinder73
Checking The Piston74
Checking The Piston Pin And Small End Bearing74
Checking The Piston Ring74
Checking The Piston Clearance75
Checking The Combination Of Piston And Cylinder75
Checking The Power Valve Hole On Cylinder75
Installing The Power Valve76
Installing The Piston Ring And Piston77
Installing The Cylinder Head And Cylinder77
Removing The Clutch79
Removing The Clutch Boss80
Checking The Clutch Housing And Boss81
Checking The Primary Driven Gear81
Checking The Clutch Springs81
Checking The Friction Plates81
Kick Shaft And Shift Shaft83
Removing The Primary Drive Gear83
Removing The Kick Shaft And Shift Shaft84
Removing The Kick Shaft Assembly85
Removing The Shift Guide And Shift Lever Assembly85
Checking The Kick Shaft And Ratchet Wheel85
Checking The Stopper Lever85
Installing The Shift Guide And Shift Lever Assembly86
Installing The Shift Shaft86
Installing The Kick Shaft Assembly86
Installing The Kick Idle Gear87
Installing The Primary Drive Gear87
Removing The Ypvs Governor88
Removing The Governor89
Checking The Governor Groove89
Checking The Bearing89
Installing The Governor89
Disassembling The Water Pump90
Removing The Impeller Shaft91
Removing The Oil Seal91
Checking The Impeller Shaft91
Checking The Oil Seal91
Removing The Cdi Magneto93
Removing The Rotor94
Checking The Cdi Magneto94
Checking The Woodruff Key94
Installing The Cdi Magneto94
Engine Removal95
Removing The Engine95
Removing The Drive Sprocket97
Installing The Engine97
Installing The Drive Sprocket97
Installing The Brake Pedal97
Crankcase And Crankshaft99
Removing The Crankshaft99
Removing The Segment101
Disassembling The Crankcase101
Removing The Crankcase Bearing101
Checking The Crankcase101
Installing The Crankcase Bearing102
Installing The Oil Seal102
Installing The Crankshaft102
Removing The Transmission, Shift Cam And Shift Fork104
Shift Cam And Shift Fork104
Removing The Transmission105
Checking The Gears105
Installing The Transmission105
Checking The Shift Fork, Shift Cam And Segment105
Front Wheel And Rear Wheel107
Removing The Front Wheel107
Removing The Rear Wheel108
Removing The Wheel Bearing109
Checking The Wheel109
Checking The Wheel Axle109
Checking The Brake Disc109
Installing The Rear Wheel110
Front Brake And Rear Brake112
Removing The Front Brake112
Removing The Rear Brake113
Disassembling The Brake Caliper114
Disassembling The Brake Master Cylinder115
Draining The Brake Fluid116
Removing The Brake Caliper Piston116
Removing The Brake Caliper Piston Seal Kit116
Checking The Brake Master Cylinder116
Checking The Brake Caliper117
Checking The Brake Hose117
Installing The Brake Caliper Piston117
Installing The Front Brake Caliper117
Installing The Rear Brake Caliper118
Installing The Brake Master Cylinder Kit118
Installing The Front Brake Master Cylinder118
Installing The Rear Brake Master Cylinder119
Installing The Front Brake Hose119
Installing The Rear Brake Hose120
Filling The Brake Fluid120
Removing The Front Fork122
Disassembling The Front Fork123
Removing The Damper Assembly124
Removing The Adjuster124
Removing The Inner Tube124
Removing The Base Valve124
Checking The Base Valve125
Checking The Collar125
Checking The Fork Spring125
Checking The Inner Tube125
Installing The Front Fork128
Removing The Handlebar130
Disassembling The Throttle131
Removing The Brake Master Cylinder132
Removing The Grip132
Checking The Handlebar132
Assembling The Throttle132
Removing The Steering135
Removing The Steering Ring Nut137
Removing The Lower Bearing137
Removing The Bearing Race137
Checking The Steering Stem137
Removing The Swingarm139
Disassembling The Swingarm140
Removing The Cap141
Removing The Bearing141
Checking The Swingarm141
Checking The Relay Arm141
Installing The Swingarm142
Removing The Rear Shock Absorber144
Rear Shock Absorber145
Installing The Bearing146
Installing The Spring (Rear Shock Absorber)147
Installing The Rear Shock Absorber147
Electrical Components And Wiring Diagram150
Ignition System151
Spark Gap Test152
Checking The Couplers, Leads And Ignition Coil Connection152
Checking The Engine Stop Switch152
Checking The Ignition Coil152
Checking The Neutral Switch153
Checking The Cdi Unit153
Solenoid Valve System154
Checking The Couplers And Leads Connection155
Checking The Solenoid Valve Operation155
Checking The Solenoid Valve Coil155
Throttle Position Sen Sor System156
Checking The Throttle Position Sensor Coil157
Changing And Adjusting The Throttle Position Sensor157
Throttle Position Sensor System157
Checking Couplers/Leads Connection157
Checking The Throttle Position Sensor Input Voltage158
Engine Tuning159
Atmospheric Conditions And Carburetor Settings159
Effect Of Setting Parts In Relation To Throttle Valve159
Adjusting The Main Jet159
Adjusting The Power Jet160
Adjusting The Pilot Jet160
Adjusting The Jet Needle Groove Position160
Relationship With Throttle Opening161
Carburetor Setting Parts161
Road Condition And Examples Of Carburetor Setting162
Examples Of Carburetor Setting Depending On Symptom163
Change Of The Heat Range Of Spark Plugs164
Selection Of The Secondary Reduction Ratio (Sprocket)164
Drive And Rear Wheel Sprockets Setting Parts164
Front Fork Setting164
Setting Of Spring After Replacement165
Front Fork Setting Parts165
Rear Suspension Setting165
Choosing Set Length165
Rear Shock Absorber Setting Parts166
Suspension Setting (Front Fork)167
Suspension Setting (Rear Shock Absorber)168