1985-1986 Honda ATC250R Shop Manual, Page 79Get this manual
CYLINDER HEADCYLINDERPISTON
Measure the piston pin bore 1.0SERVICE LIMIT: 18.03 mm (0.710 in) Check the piston pin for wear and excessive discolorationMeasure the piston pin 0.0SERVICE LIMIT: 17.98 mm (0.708 in) Calculate the piston pin-to-piston clearanceSERVICE LIMIT: 0.03 mm (0.001 in)