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 DiscClutch Cover Installation
Using a cleaning fluid, clean off any oil or dirt that may
be on the silicone sealant coating area. Dry them with a
clean cloth.
Apply silicone sealant to the area [A] where the mating
surface of the crankcase touches the clutch cover gasket.
Sealant - Liquid Gasket, TB1211F: 92104-000 ...
Spring Plate Free Play Adjustment
NOTE
The free play adjustment is performed by replacing the
steel plate(s).
Measure the clutch spring plate free play (see Clutch
Spring Plate Free Play Measurement), and then replace
the steel plate(s) which brings the free play within the
usable range.
Spring Plate Free Play
Usable ...
Camshaft Chain Tensioner Installation
Replace the O-ring [A] with a new one.
Apply grease to the new O-ring.
Release the stopper [B] and push the push rod [C] into the
interior of the tensioner body [D] so that the position of the
push rod is 3 or 4 notches [E] as shown in the figure.
Install the tensioner body so that the ...