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 DiscBrake Fluid Leak (Brake Hose and Pipe) Inspection
For KIBS equipped models, remove the fuel tank (see
Fuel Tank Removal in the Fuel System (DFI) chapter).
Apply the brake lever or pedal and inspect the brake fluid
leak from the brake hoses [A], pipes (KIBS equipped models)
[B] and fittings [C].
If the brake fluid leaked from any posit ...
Brake Light Switches
When either the front or rear brake is
applied, the brake light goes on. The
front brake light switch requires no adjustment,
but the rear brake light switch
should be adjusted in accordance with
the Periodic Maintenance Chart.
Inspection
Turn the ignition key to “ON”.
The brake ligh ...
Rear Wheel Installation
Apply high-temperature grease to the grease seal lips.
Fit the collars on the both sides of the hub.
Left Side Collar [A]
Right Side Collar [B] (with Flange)
Engage the drive chain with the rear sprocket.
Install the caliper bracket [A] onto the stopper [B] of the
swingarm.
...