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 InspectionFuel Injector Fuel Line Inspection
Remove:
Fuel Tank (see Fuel Tank Removal)
Air Cleaner Housing (see Air Cleaner Housing Removal)
Disconnect:
Primary and Secondary Fuel Hoses (see Fuel Hose Replacement
in the Periodic Maintenance chapter)
Do not remove the nozzle assy from the air cleaner housing.
Be sure to pla ...
Air Switching Valve (Service Code 64)
Air Switching Valve Removal/Installation
Refer to the Air Switching Valve Removal/Installation in
the Engine Top End chapter.
Air Switching Valve Inspection
Refer to the Air Switching Valve Unit Test in the Electrical
System chapter.
If the air switching valve [A] is normal, check ...
Hoses and Pipes
Hose Installation
Install the hoses and pipes, being careful to follow bending
direction. Avoid sharp bending, kinking, flattening or
twisting.
Run the hoses (see Cable, Wire, and Hose Routing section
in the Appendix chapter).
Install the clamp [A] as near as possible to the hose end
...