Yamaha XVS6501997 Service Manual page 252

SHAFT DRIVE
Inspection notes
1. Investigate any unusual noises.
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The following noises may indicate a me-
chanical defect:
a. A rolling "rumble" during coasting, accel-
eration, or deceleration. The noise in-
creases with rear wheel speed, but does
not increase with higher engine or trans-
mission speeds.
Diagnosis: Possible wheel bearing dam-
age
b. A whining noise that varies with accelera-
tion and deceleration.
Diagnosis: Possible incorrect reassemb-
ly, too little gear lash
CAUTION:
Insufficient gear lash is extremely destruc-
tive to the gear teeth. If a test ride following
reassembly indicates this condition, stop
riding immediately to minimize gear dam-
age.
c. A slight "clunk" evident at low speed opera-
tion. This noise must be distinguished from
normal motorcycle operation.
Diagnosis: Possible broken gear teeth
Stop riding immediately if broken gear teeth
are suspected. This condition could result
in a locking of the shaft drive assembly,
causing loss of control of the motorcycle
and possible injury to the rider.
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2. Inspect:
S Drained oil
Drained oil contains a large amount of
metal particles ! Check the bearing for
seizure.
NOTE:
A small amount of metal particles in the oil is
normal.
6-52
CHAS