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 DiscWater Temperature Sensor Removal/Installation
NOTICE
Never drop the water temperature sensor especially
on a hard surface. Such a shock to the sensor can
damage it.
Remove the throttle body assy (see Throttle Body Assy
Removal in the Fuel System (DFI) chapter).
Drain the coolant (see Coolant Change in the Periodic
Maintenance c ...
Key Registration
Case 1: When the ignition key has been lost or additional
spare ignition key is required.
Prepare a new spare ignition key.
Cut the key in accordance with the shape of the current
ignition key.
Remove the rear seat (see Rear Seat Removal in the
Frame chapter).
Remove the immobilizer/K ...
Throttle Grip and Cables
Free Play Inspection
Refer to the Throttle Control System Inspection in the Periodic
Maintenance chapter.
Free Play Adjustment
Refer to the Throttle Control System Inspection in the Periodic
Maintenance chapter.
Cable Installation
Install the throttle cables in accordance with the Cable,
...