Piston Kit. As the leader in forged racing pistons, JE Pistons has applied over 75 years of experience to its wide range of premium forged pistons for dirt bike and other off-road motorcycle engines. Engineered, forged and machined 100% in the U.S.A., JE Pistons are designed for each specific engine and riding application to provide the ultimate combination of durability and performance. From the motocross track to the trail and everything in between, JE Pistons' performance is proven with every handful of throttle and wave of the checkered flag. Equip your bike with the best in forged pistons. Forged in the U.S.A. using 2618 aluminum, yielding high tensile strength needed for high-demand performance applications. Designed specifically for each engine and use application to provide optimized performance durability.