1985-1986 Honda Fourtrax 125 TRX125 Shop Manual, Page 86Get this manual
CYLINDER PISTON
Measure the piston skirt diameter at 10 mm from the bottom and 90" to the piston pin boreSERVICE LIMIT: 54 .90 mm (2.161 in )
Measure the piston pin hole I.D SERVICE LIMIT: 15.04 mm (0.592 in)