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.)
Cylinder (Upper Crankcase) Wear Inspection
Piston Ring, Piston Ring Groove Wear InspectionRocker 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 ...
Subthrottle Valve Actuator Resistance Inspection
Turn the ignition switch to OFF.
Disconnect the subthrottle valve actuator connector [A].
Connect a digital meter to the subthrottle valve actuator
connector [A].
Measure the subthrottle valve actuator resistance.
Subthrottle Valve Actuator Resistance
Connections: Y/BK lead [1 ...
Stick Coil Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the ECU (see ECU Removal in the Fuel System
(DFI) chapter).
Do not disconnect the ECU connectors.
Connect a digital meter [A] to the connector [B] with the
needle adapter set.
Special Tool - N ...