Piston Kit 8547D2004 Stroke Piston KitIn house designed and manufactured; all forgings are produced in Wssners company owned forging operation 4 stroke pistons are made using a double bridged forging design Lightweight pistons with the tightest piston wall clearances in the industry give you a quieter running engine Standard and oversize pistons for most models, with high compression ratios available for 4 stroke applications All piston skirts are supplied with a Moly