Poor Medium-And-High-Speed Performance; Shifting Is Difficult; Shift Pedal Does Not Move; Jumps Out Of Gear - Yamaha YZ 2016 Series Owner's Service Manual

POOR MEDIUM-AND-HIGH-SPEED PER-
EASB296371
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

SHIFTING IS DIFFICULT

EASB296372
Refer to "CLUTCH" on page 5-41.
EASB296373

SHIFT PEDAL DOES NOT MOVE

Engine
1. Shift shaft
• Bent shift shaft
2. Shift drum and shift forks
• Foreign object in a shift drum groove
• Seized shift fork
• Bent shift fork guide bar
3. Transmission
• Seized transmission gear
• Foreign object between transmission gears
• Improperly assembled transmission

JUMPS OUT OF GEAR

EASB296374
Engine
1. Shift shaft
• Incorrect shift pedal position
• Improperly returned stopper lever
2. Shift forks
• Worn shift fork
3. Shift drum
• Incorrect axial play
• Worn shift drum groove
4. Transmission
• Worn gear dog

CLUTCH SLIPS

EASB296375
Engine
1. Clutch
• Improperly assembled clutch
• Loose or fatigued clutch spring
• Worn friction plate
• Worn clutch plate
TROUBLESHOOTING
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (low)
• Deteriorated oil

CLUTCH DRAGS

EASB296376
Engine
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

OVERHEATING

EASB296377
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
Fuel system
1. Throttle body
• Damaged or loose throttle body joint
2. Air filter
• Clogged air filter element
9-2