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 DiscTechnical Information-Power Mode
The rider can choose from three engine power modes to suit their preferences
and road conditions.
The FI ECU controls the engine power by adjusting fuel injection, air intake,
and ignition timing. It
enables three-mode selection: Full Power (Mode F), Middle Power (Mode M), and
Low Power (M ...
Camshaft Chain Tensioner Removal
NOTICE
This is a non-return type camshaft chain tensioner.
The push rod does not return to its original position
once it moves out to take up camshaft chain slack.
Observe all the rules listed below.
When removing the tensioner, do not take out the
mounting bolts only halfway. Retighteni ...
Balancer Assemble
Apply molybdenum disulfide oil solution to the ribs of the
balancer [A].
Apply molybdenum disulfide oil solution to the ribs of the
balancer gear [A].
Check that the rubber dampers [B] are in place.
Face the linked portion [C] to the bottom.
Assemble the balancer weight ...