Yamaha 2011 FZ8NA(C) Service Manual page 471

Fuel system
1. Throttle body (-ies)
• Damaged or loose throttle body joint
• Improperly synchronized throttle bodies
• Improperly adjusted engine idling speed
(idle adjusting screw)
• Improper throttle cable free play
• Flooded throttle body
• Faulty air induction system
Electrical system
1. Battery
• Discharged battery
• Faulty battery
2. Spark plug(s)
• Incorrect spark plug gap
• Incorrect spark plug heat range
• Fouled spark plug
• Worn or damaged electrode
• Worn or damaged insulator
3. Ignition coil(s)
• Broken or shorted primary or secondary
coils
• Cracked or broken ignition coil
4. Ignition system
• Faulty ECU
• Faulty crankshaft position sensor
• Faulty cylinder identification sensor
• Broken pickup rotor straight key
EAS30450
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. Throttle body (-ies)
• Faulty throttle body
2. Fuel pump
• Faulty fuel pump
EAS28530
FAULTY GEAR SHIFTING
Shifting is difficult
Refer to "Clutch drags".
EAS28540
SHIFT PEDAL DOES NOT MOVE
TROUBLESHOOTING
Shift shaft
• Improperly adjusted shift rod
• 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
EAS28550
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
EAS28560
FAULTY CLUTCH
Clutch slips
1. Clutch
• Improperly assembled clutch
• Improperly adjusted clutch cable
• 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 pull rod
• Broken clutch boss
• Burnt primary driven gear bushing
• Match marks not aligned
9-2