1997-2001 Honda TRX250 Fourtrax Recon Service Manual, Page 121Get this manual
CYLINDER HEADCYLINDERPISTON Inspect the piston for wear or damageMeasu the diameter of th piston at18 mm (0.20.7 infrom the bottom and 90 degrees to the pist on pin hole SERVICE LIMIT: 68.4 mm 12.69 in)
M easure the piston pin bore SERVICE LIMIT: 15.04 mm (0.592 in)
Measure the 0.0 of the piston pinSERVICE LIMIT: 14.96 mm (0.589 in) Calculate the piston-to-piston pin clearance SERVICE LIMIT: .020 mm (0.0008 in)