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 DiscRefreshing Charge
Remove the battery (see Battery Removal).
Do refresh charge by following method according to the
battery terminal voltage.
WARNINGThis battery is sealed type. Charge with
current and
time as stated below.
Terminal Voltage: 12.0 12.7
V
Standard Charge (see following ...
Brake Pad Wear Inspection
Remove the brake pads (see Front/Rear Brake Pad Removal
in the Brakes chapter).
Check the lining thickness [A] of the pads in each caliper.
If the lining thickness of either pad is less than the service
limit [B], replace both pads in the caliper as a set.
Front Brake Pad [C]
Rea ...
Tachometer
The tachometer shows the engine
speed in revolutions per minute (r/min,
rpm).
On the right side of the tachometer
face is a portion called the “red zone”.
Engine r/min (rpm) in the red zone is
above maximum recommended engine
speed and is also above the range for
good performance.
...