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 DiscSpecifications
Whenever you see the symbols
shown below, heed their instructions!
Always follow safe operating and maintenance
practices.
DANGER
DANGER indicates a hazardous
situation which, if not avoided,
will result in death or serious injury.
WARNINGWARNING indicates a hazardous
situation whi ...
Mode-switching
Depress the S-KTRC button on the left handlebar switch
to change the mode. The mode can be changed only when
the throttle grip is closed completely.
The S-KTRC OFF can be selected only when the motorcycle
is at a stop. Changing to mode 1 from S-KTRC OFF
is possible while riding.
NOTE
...
Radiator Inspection
Remove the radiator (see Radiator and Radiator Fan Removal).
Check the radiator core.
If there are obstructions to air flow, remove them.
If the corrugated fins [A] are deformed, carefully
straighten them.
If the air passages of the radiator core are blocked more
than 20% by unremovable ...