Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionCaliper Installation
Install the caliper and brake hose lower end.
For the front caliper, be sure to install the collars [A].
Replace the washers on each side of hose fitting with new
ones.
Touch the brake hoses [A] to the stopper [B] of the caliper.
Front Calipers [C]
Rear Caliper [D]
Tighten:
To ...
Piston Wear Inspection
Measure the outside diameter [A] of each piston 5 mm
(0.20 in.) [B] up from the bottom of the piston at a right
angle to the direction of the piston pin.
If the measurement is under service limit, replace the piston.
Piston Diameter
Standard: 75.959 75.974 mm
(2.9905 2.9911 in.)
...
Connecting Rod Bend Inspection
Remove the connecting rod big end bearing inserts, and
reinstall the connecting rod big end cap.
Select an arbor [A] of the same diameter as the connecting
rod big end, and insert the arbor through the connecting
rod big end.
Select an arbor of the same diameter as the piston pin
and ...