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 DiscFor Primary Fuel Injectors
Remove the air cleaner housing (see Air Cleaner Housing
Removal).
Disconnect the injector connector and connect the harness
adapter [A] between these connectors as shown in
the figure.
Main Harness [B]
Primary Fuel Injector #1 [C]
Special Tool - Measuring Adapter: 57001-1700
...
Compression Damping Force Adjustment
To adjust the compression damping force, turn the compression
damping adjuster [A].
The standard adjuster setting is the 4 1/2 turns out from
the fully clockwise position.
WARNINGIf both adjusters are not adjusted
equally, handling
may be impaired and a hazardous condition ma ...
KIBS Troubleshooting Outline
When an abnormality in the system occurs, the ABS indicator
light (LED) and KIBS indicator light (LED) light up and
the KIBS warning symbol are displayed on the LCD (Liquid
Crystal Display) to alert the rider. In addition, the nature of
the fault is stored in the memory of the KIBS hydraulic uni ...