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 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 ...
Cooling System Flushing
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cooling
system. If this accumulation is not removed, it will clog
up the water passage and considerable reduce the efficiency
...
Starter Motor Assembly
Install the positive brush assy [A] and the starter motor
terminal [B] as shown in the figure.
Replace the O-ring [C] with a new one, and install it.
Install:
Brush Springs [A]
Negative Brush Assy [B]
Turn the stopper side [C] to inside.
Tighten:
Torque - Brush Holder S ...