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 DiscRocker Arm Removal
Squeeze the brake lever slowly and hold it with a band.
Remove the front footpeg bracket bolts.
Raise the rear wheel off the ground with the jack (see
Rear Shock Absorber Removal).
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
Remove:
Lower Rear Shock Absorber B ...
Water Temperature Sensor Inspection
Remove the water temperature sensor (see Water Temperature
Sensor Removal/Installation in the Fuel System
(DFI) chapter).
Suspend the sensor [A] in a container of coolant so that
the temperature-sensing projection [C] is submerged.
Suspend an accurate thermometer [B] with temperature
...
City Light (LED) Removal/Installation
Remove:
Upper Fairing Assembly (see Upper Faring Assembly
Removal in the Frame chapter)
Headlight (see Headlight Removal)
Remove the screws [A], and take the city light [B] off the
upper fairing assembly.
Installation is the reverse of removal. Note the following.
When inst ...