Yamaha YZ125X 2023, Owner'S Manual

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TROUBLESHOOTING
7-7
EAM30511
TROUBLESHOOTING OF TRANSMISSION
Clutch noise
Damaged or worn primary driven
gear
Replace the primary drive gear or
crankshaft, and the clutch housing
as a set.
Loose clutch boss nut
Tighten the clutch boss nut to the
specified torque.
Fatigued clutch damper Replace the clutch housing.
Worn clutch housing bearing
Replace the clutch housing bear-
ing.
Worn pressure plate bearing
Replace the pressure plate bear-
ing.
Symptom Possible cause Actions
Difficult or impossible to shift
transmission gear
Clutch drags Refer to “Clutch drags”.
Improperly adjusted shift rod
Adjust the shift rod installation
length.
Bent shift shaft Replace the shift shaft.
Foreign object in a shift drum
groove
Remove foreign object from shift
drum groove.
Damaged shift drum Replace the shift drum.
Seized shift fork
Replace the shift fork and shift fork
guide bar as a set.
Bent shift fork guide bar Replace the shift fork guide bar.
Foreign object between transmis-
sion gears
Remove foreign object from trans-
mission gears.
Seized transmission gear
Replace the seized gear and the
axle as a set.
Improperly assembled transmis-
sion
Reassemble the transmission axle
assembly.
Jumps out of gear
Incorrect shift pedal position Adjust the shift pedal position.
Improperly returned stopper lever Replace the stopper lever spring.
Bent or worn shift fork Replace the shift fork.
Shift drum incorrect axial play Replace the shift drum.
Worn shift drum groove Replace the shift drum.
Worn transmission gear dog Replace the transmission gear.
Transmission noise
Damaged or worn transmission
gear
Replace the transmission gear.
Worn main axle spline Replace the main axle.
Worn drive axle spline Replace the drive axle.
Worn bearing Replace the bearing.
Symptom Possible cause Actions