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 DiscStick Coil Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the ECU (see ECU Removal in the Fuel System
(DFI) chapter).
Do not disconnect the ECU connectors.
Connect a digital meter [A] to the connector [B] with the
needle adapter set.
Special Tool - N ...
Subthrottle Sensor Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter)
Disconnect the subthrottle sensor connector and connect
the harness adapter [A] between these connectors.
Spec ...
Tire Repair
Currently two types of repair for tubeless tires have come
into wide use. One type is called a temporary (external) repair
which can be carried out without removing the tire from
the rim, and the other type is called permanent (internal)
repair which requires tire removal. It is generally unders ...