Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionMaster Cylinder Inspection (Visual Inspection)
Remove the master cylinders (see Front/Rear Master
Cylinder Removal).
Disassemble the front and rear master cylinders (see
Master Cylinder Rubber Parts Replacement in the Periodic
Maintenance chapter).
Check that there are no scratches, rust or pitting on the
inner wall [A] of each ma ...
Drive Chain Slack Adjustment
Remove the cotter pin [A], and loosen the rear axle nut
[B].
Loosen the both chain adjuster locknuts [C].
If the chain is too loose, turn out the left and right chain
adjusters [D] evenly.
If the chain is too tight, turn in the left and right chain
adjusters evenly, and kick the wheel f ...
Cooling System Flushing
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cooling
system. If this accumulation is not removed, it will clog
up the water passage and considerable reduce the efficiency
...