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 DiscAir Intake Solenoid Valve (Service Code 2d, Equipped Models)
Air Intake Solenoid Valve Removal/Installation
Refer to the Air Intake Solenoid Valve Removal/Installation
in the Fuel System (DFI) chapter.
Air Intake Solenoid Valve Inspection
Refer to the Air Intake Solenoid Valve Unit Test in the
Electrical System chapter.
If the air intake ...
Wear Inspection
Remove the left front footpeg bracket
bolts.
A. Front Footpeg Bracket
B. Bolts
Remove the bolts and chain cover.
A. Bolts
B. Chain Cover
Stretch the chain taut either by using
the chain adjusters, or by hanging a
10 kg (22 lb) weight on the chain.
Measure the lengt ...
Thermostat Installation
Replace the O-rings [A] with new ones, and apply grease
to them.
Assemble:
O-rings
Thermostat Housing [B]
Thermostat [C]
Thermostat Cap [D]
Install the thermostat [A] in the housing so that the air
bleeder hole [B] is on top.
Tighten:
Torque - Thermostat Cap Bolts: 5.9 N ...