Motorcycle Repair: piston sizes, honda cr250r, 38mm

Question
i bought a piston for a 1987 honda cr250r but it has to much play in it and i was wondering what would be the next size, the piston that i bought was a 66.38mm.

Answer
Gerald, Just giving you a number may not help. If the cylinder has been bored you need to get the piston that goes with the bore measurement. Some shops measure the bore and find the largest worn portion and order a piston the next size bigger. The cylinder is then bored to fit the piston.