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 DiscKIBS Warning Indicator Light (For models equipped
with KIBS)
The yellow warning indicator light in
the meter unit functions as the KIBS
warning indicator light. The yellow
warning indicator light and warning
symbol “KIBS” go on if there is a malfunction
in the KIBS system. When the
warning light is on, the KIBS system
stops functioning. However, th ...
Self-Diagnosis Procedures
NOTE
Use a fully charged battery when conducting
self-diagnosis. Otherwise, the light (LED) and symbol
do not light or blink.
Turn the ignition switch to ON.
When a problem occurs with DFI system and ignition system,
the warning indicator light (LED) [A] goes on and
FI warning symbol ...
Immobilizer Amplifier Replacement
Remove the upper fairing assembly (see Upper Fairing
Assembly Removal in the Frame chapter).
Disconnect the connector [A].
Pull out the immobilizer amplifier [B] together with the rubber
protector [C] from the air intake duct [D].
ECU Replacement
Refer to the ECU Removal/Instal ...