If a master cylinder or piston shows any damage, replace them.

If a cup is worn, damaged softened (rotted), or swollen, the piston assembly should be replaced to renew the cups.
If fluid leakage is noted at the brake lever, the piston assembly should be replaced to renew the cups.
If they are damaged, replace them.
If the springs are damaged, replace them.
If the relief port becomes plugged, the brake pads will drag on the disc. Blow the ports clean with compressed air.
Front Master Cylinder [I] Rear Master Cylinder [J]

Rear Master Cylinder Installation
Brake DiscStarter Clutch Removal
Remove:
Torque Limiter (see Torque Limiter Removal)
Transmission Assy (see Transmission Assy Removal)
Starter Clutch Shaft Holder Bolt [A]
Starter Clutch Shaft Bolt [B]
Starter Clutch Shaft Holder [C]
Remove the starter clutch shaft [A] using a suitable M8
bolt [B].
Take ...
Radiator and Cooling Fan
Check the radiator fins for obstruction
by insects or mud. Clean off
any obstructions with a stream of
low-pressure water.
WARNINGThe cooling fan spins at high
speed and can cause serious
injuries. Keep your hands and
clothing away from the cooling
fan blades at all times.
...
Spring Tension Inspection
Since a spring becomes shorter as it weakens, check its
free length [A] to determine its condition.
If the spring of either fork leg is shorter than the service
limit, it must be replaced. If the length of a replacement
spring and that of the remaining spring vary greatly, the
remaining s ...