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 InspectionClutch Cover Installation
Using a cleaning fluid, clean off any oil or dirt that may
be on the silicone sealant coating area. Dry them with a
clean cloth.
Apply silicone sealant to the area [A] where the mating
surface of the crankcase touches the clutch cover gasket.
Sealant - Liquid Gasket, TB1211F: 92104-000 ...
Front Master Cylinder Installation
Apply silicone grease to the sliding surface of the brake
lever pivot bolt.
Tighten:
Torque - Brake Lever Pivot Bolt: 1.2 N·m (0.12 kgf·m, 11
in·lb)
Brake Lever Pivot Bolt Nut: 5.9 N·m (0.60 kgf·m,
52 in·lb)
Assemble the reservoir [A] and the bracket [B] as shown
in the figu ...
Gear Position Switch Removal
Remove:
Oil Pump (see Oil pump Removal in the Engine Lubrication
System chapter)
Engine Sprocket (see Engine Sprocket Removal in the
Final Drive chapter)
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Disconnect the connector [A].
Remove:
Screws [A]
...