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 DiscTurn Signal Switch
When the turn signal switch is
pushed to the left ( ) or right
( ), the corresponding turn signals
blink on and off.
To stop blinking, push the switch in.
Horn Button
When the horn button is pushed, the
horn sounds
LAP/Passing Button
When the LAP/passing button is
pushed, the headlight hi ...
Fuse Inspection
Remove the fuse.
Inspect the fuse element.
If it is blown out, replace the fuse. Before replacing a
blown fuse, always check the amperage in the affected
circuit. If the amperage is equal to or greater than the
fuse rating, check the wiring and related components for
a short circuit.
...
Battery Ground
Before completing any service on the motorcycle, disconnect
the battery cables from the battery to prevent the engine
from accidentally turning over. Disconnect the ground
cable (–) first and then the positive (+). When completed
with the service, first connect the positive (+) cable to the
p ...