KLX140 Forged piston kit for the 170cc big bore kits (63mm).    These pistons are extremely strong and durable.   They are cut to work with stock valves or the 31/25 race head valves.   They will not work with the large 34/29 race head valves.   This is a piston kit only - it includes the piston, rings, circlips, and piston pin.   No gaskets are included.