Checking Noises - Yamaha 5YF2-AE1 Service Manual

TROUBLESHOOTING
EBS00156

CHECKING NOISES

1. Investigate any unusual noises.
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a. A "rolling rumble" noise during coasting,
acceleration, or deceleration. The noise
increases with rear wheel speed, but it does
not increase with higher engine or transmis-
sion speeds.
Diagnosis: Possible wheel bearing damage.
b. A "whining" noise that varies with accelera-
tion and deceleration.
Diagnosis: Possible incorrect reassembly,
too-little gear lash.
CAUTION:
_
Too little gear lash is extremely destructive
to the gear teeth. If a test ride following
reassembly indicates this condition, stop
riding immediately to minimize gear dam-
age.
c. A slight "thunk" evident at low speed opera-
tion. This noise must be distinguished from
normal machine operation.
Diagnosis: Possible broken gear teeth.
WARNING
_
Stop riding immediately if broken gear
teeth are suspected. This condition could
result in the shaft drive assembly locking
up, causing loss of control of the machine
and possible injury to the rider.
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2. Check:
• drained oil
Drained oil shows large amounts of metal
particles → Check the bearing for seizure.
NOTE:
_
A small amount of metal particles in the oil is
normal.
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DRIV
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