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 DiscWheel/Tire Damage Inspection
Remove any imbedded stones [A] or other foreign particles
[B] from tread.
Visually inspect the tire for cracks and cuts, and replace
the tire if necessary. Swelling or high spots indicate internal
damage, requiring tire replacement.
Visually inspect the wheel for cracks, cuts and dents ...
Tie-Rod and Rocker Arm Bearing Installation
Replace the needle bearings [A] and oil seals with new
ones.
Apply plenty of grease to the lips of the oil seals.
Install the needle bearings and oil seals position as shown
in the figure.
Screw the needle bearing driver into the driver holder.
Insert the needle bearing driver into th ...
Check 2-1: Speedometer Inspection
Using the suitable stand, raise the rear wheel off the
ground.
Rotate the rear wheel by hand or start the engine.
Check that the display changes speedometer.
If the display function does not work, check the following
parts.
Rear Wheel Rotation Sensor (see Wheel Rotation Sensor
Inspe ...