Faulty Drive Train - Yamaha YFM400FAR Service Manual

FAULTY DRIVE TRAIN

The following conditions may indicate damaged shaft drive components:
Symptoms
1.A pronounced hesitation or "jerky" movement
during acceleration, deceleration, or sustained
speed. (This must not be confused with
engine surging
characteristics.)
2.A "rolling rumble" noticeable at low speed; a
high-pitched whine; a "clunk" from a shaft
drive component or area.
3.A locked-up condition of the shaft drive
mechanism, no power transmitted from the
engine to the front and/or rear wheels.
NOTE:
Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite subtle and
difficult to distinguish from normal machine operating noise. If there is reason to believe these
components are damaged, remove the components and check them.
FAULTY DRIVE TRAIN
A.Bearing damage.
B.Improper gear lash.
or transmission
C.Gear tooth damage.
D.Broken drive shaft.
E.Broken gear teeth.
F.Seizure due to lack of lubrication.
G.Small foreign objects lodged between the
10 - 3
Possible Causes
moving parts.
TRBL
SHTG