Troubleshooting - Yamaha YFM250XL(C) Service Manual

FINAL DRIVE GEAR AND DRIVE SHAFT

TROUBLESHOOTING

The following conditions may indicate damage drive train components:
Symptoms
1.A pronounced hesitation or "jerky" move-
ment during acceleration, deceleration, or
sustained speed. (this must not be con-
fused with engine surging or transmission
characteristics.)
2.A "rolling rumble" noticeable at low speed;
a high-pitched "whine"; a "clank" from a
drive train component or area.
3.A locked-up condition of the drive train
mechanism, no power transmitted from
engine to rear wheel.
NOTE:
Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite sub-
tle and difficult to distinguish from normal machine operating noise. If there is reason to
believe these components are damaged, remove the components for specific inspection.
Possible causes
A. Bearing damage.
B. Improper gear lash.
C. Gear tooth damage.
D. Broken drive shaft.
E. Broken gear teeth.
F. Seizure due to lack of lubrication.
G. Small foreign object lodged between
moving parts.
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