If the measurement is under service limit, replace the piston.
Piston Diameter
Standard: 75.959 75.974 mm
(2.9905 2.9911 in.)
Service Limit: 75.81 mm (2.985 in.)
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 ...
Piston Ring Groove Width Inspection
Measure the piston ring groove width.
Use a vernier caliper at several points around the piston.
Piston Ring Groove Width
Standard:
Top [A] 0.82 0.84 mm (0.0323
0.0331 in.)
Second [B] 0.82 0.84 mm
(0.0323 0.0331 in.)
Service Limit:
0.92 mm (0.036 in.)
Second 0.92 mm (0.036 in.)
...
Piston Removal
Remove:
Crankshaft (see Crankshaft Removal)
Remove the piston together with the connecting rod to the
cylinder head side.
NOTICE
Discard the connecting rod bolts and nuts. To prevent
damage to the crankpin surfaces, do not allow
the connecting rod bolts to bump against the
crankpins. ...