TROUBLE SHOOTING
9-2
3. Ignition system
• Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key
EAS1SM1354
POOR MEDIUM-AND-HIGH-SPEED PER-
FORMANCE
Refer to “STARTING FAILURES” on page 9-1.
Engine
1. Air filter
• Clogged air filter element
Fuel system
1. Fuel pump
• Faulty fuel pump
2. Throttle body
• Defective throttle body
3. ECU
• Faulty ECU
EAS1SM1355
FAULTY GEAR SHIFTING
Shifting is difficult
Refer to “CLUTCH” on page 5-35.
EAS1SM1356
SHIFT PEDAL DOES NOT MOVE
Shift shaft
• Bent shift shaft
Shift drum and shift forks
• Foreign object in a shift drum groove
• Seized shift fork
• Bent shift fork guide bar
Transmission
• Seized transmission gear
• Foreign object between transmission gears
• Improperly assembled transmission
EAS1SM1357
JUMPS OUT OF GEAR
Shift shaft
• Incorrect shift pedal position
• Improperly returned stopper lever
Shift forks
• Worn shift fork
Shift drum
• Incorrect axial play
• Worn shift drum groove
Transmission
• Worn gear dog
EAS1SM1358
FAULTY CLUTCH
Clutch slips
1. Clutch
• Improperly assembled clutch
• Loose or fatigued clutch spring
• Worn friction plate
• Worn clutch plate
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (low)
• Deteriorated oil
Clutch drags
1. Clutch
• Unevenly tensioned clutch springs
• Warped pressure plate
• Bent clutch plate
• Swollen friction plate
• Bent clutch push rod
• Damaged clutch boss
• Burnt primary driven gear bushing
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (high)
• Deteriorated oil
EAS1SM1359
OVERHEATING
Engine
1. Cylinder head and piston
• Heavy carbon buildup
• Clogged coolant passages
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity
• Inferior oil quality
Cooling system
1. Coolant
• Low coolant level
2. Radiator
• Damaged or leaking radiator
• Faulty radiator cap
• Bent or damaged radiator fin
3. Water pump
• Damaged or faulty water pump
• Damaged hose
• Improperly connected hose
• Damaged pipe
• Improperly connected pipe
Summary of Contents for YZ250F(E)
Page 4: ......
Page 10: ......
Page 12: ......
Page 16: ...LOCATION OF IMPORTANT LABELS 1 2 EUR...
Page 17: ...LOCATION OF IMPORTANT LABELS 1 3 AUS NZL ZAF...
Page 42: ...CLEANING AND STORAGE 1 28...
Page 68: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25...
Page 70: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 27...
Page 72: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 29...
Page 74: ...CABLE ROUTING DIAGRAM 2 31 EAS1SM1064 CABLE ROUTING DIAGRAM...
Page 76: ...CABLE ROUTING DIAGRAM 2 33...
Page 78: ...CABLE ROUTING DIAGRAM 2 35...
Page 80: ...CABLE ROUTING DIAGRAM 2 37...
Page 82: ...CABLE ROUTING DIAGRAM 2 39...
Page 84: ...CABLE ROUTING DIAGRAM 2 41...
Page 190: ...CHAIN DRIVE 4 66...
Page 250: ...OIL PUMP AND BALANCER GEAR 5 57 c d 6 6 7 8 8 b...
Page 286: ......
Page 295: ...CHARGING SYSTEM 8 9 EAS1SM1326...
Page 321: ...FUEL PUMP SYSTEM 8 35 EAS1SM1333...
Page 322: ...ELECTRICAL COMPONENTS 8 36 ELECTRICAL COMPONENTS EAS1SM1334 9 10 1 2 3 4 5 6 7 8...
Page 324: ...ELECTRICAL COMPONENTS 8 38 CHECKING THE SWITCHES B Y P Sb 2 1...
Page 325: ...ELECTRICAL COMPONENTS 8 39 1 Engine stop switch 2 Neutral switch...
Page 334: ...ELECTRICAL COMPONENTS 8 48...
Page 342: ...LIST OF SELF DIAGNOSTIC AND FAIL SAFE ACTIONS 9 7...
Page 353: ......
Page 354: ...PRINTED IN JAPAN E PRINTED ON RECYCLED PAPER...