1986-1987 Honda TRX350 FourTrax 4X4, 1987-1989 TRX350D Foreman 4X4 Service Manual, Page 90Get this manual
CYLINDERPISTON Measure the diameter of the piston at 10 mm (0.4 in) from the bottom and 90 to the piston pin hole
SERVICE LIMIT: 80.90 mm (3.185 in)
Compare this measurement with the service limit and calculate piston-to-cylinder clearanceRefer to page 8-2 for cylinder bore inspection
SERVICE LIMIT: 0.10 mm (0.004 in)
Measure the piston pin bore
SERVICE LIMIT: 21.04 mm (O.828 in)