Yamaha WR450F 2021 Owner's Service Manual page 376

Symptom
Clutch drags
Clutch noise
Possible cause
Faulty clutch spring
Warped pressure plate
Swollen friction plate
Warped clutch plate
Bent pull rod (outer pull type)
Worn pull rod tooth (outer pull
type)
Bent push rod (inner push type)
Damaged or worn clutch boss
Seized clutch housing bushing
Improperly installed pull lever
Incorrect oil level
Incorrect oil viscosity (high)
Deteriorated oil
Damaged or worn primary driven
gear
Loose clutch boss nut
Fatigued clutch damper
Worn clutch housing bearing
Worn pressure plate bearing
9-5
TROUBLESHOOTING
Actions
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.
Replace the pull rod.
Replace the pull rod and pull lever
shaft as a set.
Replace the push rod.
Replace the clutch boss.
Replace the clutch housing.
Align the match mark on the pull
lever before installation.
Adjust the engine oil level to the
specified level.
Change to recommended engine
oil.
Change to recommended engine
oil.
Replace the primary drive gear or
crankshaft, and the clutch housing
as a set.
Tighten the clutch boss nut to the
specified torque.
Replace the clutch housing.
Replace the clutch housing bear-
ing.
Replace the pressure plate bear-
ing.