Troubleshooting Of Clutch - Yamaha YZ 2020 Series Owner's Service Manual

Symptom
Noise heard from around piston
Noise heard from around crank-
shaft
EAM30510

TROUBLESHOOTING OF CLUTCH

Manual clutch
Symptom
Clutch slippage
Possible cause
Worn or damaged piston ring
Worn or damaged piston
Worn piston (piston pin hole)
Worn or damaged piston pin
Worn or damaged cylinder bore
Carbon buildup in piston head and
combustion chamber
Worn or damaged crankshaft jour-
nal or crank pin
Cracked, worn, or damaged bal-
ancer shaft
Worn or damaged balancer drive
gear
Worn or damaged big end bearing Replace the big end bearing.
Worn or damaged crankshaft jour-
nal bearing
Worn or damaged balancer shaft
journal bearing
Possible cause
Improperly assembled clutch
Improperly adjusted clutch cable
Loose clutch spring
Fatigued clutch spring
Warped pressure plate
Worn friction plate
Warped or worn clutch plate
Incorrect oil level
Incorrect oil viscosity (low)
Deteriorated oil
9-4
TROUBLESHOOTING
Actions
Replace the piston and piston
rings as a set.
Replace the piston and piston
rings as a set.
Replace the piston and piston pin
as a set.
Replace the piston pin.
Replace the cylinder, piston, and
piston rings as a set.
Clean the piston head and com-
bustion chamber.
Replace the crankshaft.
Replace the balancer drive gear
and balancer shaft as a set.
Replace the balancer drive gear
and balancer shaft as a set.
Replace the crankshaft journal
bearing.
Replace the balancer shaft journal
bearing.
Actions
Reassemble the clutch.
Adjust the clutch lever free play.
Tighten the clutch spring bolts to
the specified torque.
Replace the clutch springs as a
set.
Replace the pressure plate.
Replace the friction plates as a
set.
Replace the clutch plates as a set.
Adjust the engine oil level to the
specified level.
Change to recommended engine
oil.
Change to recommended engine
oil.