S&S Cycle 103 Replacement 3.875 Bore Piston Kit For Harley The S&S 103 Replacement Piston Kit serves as a direct replacement for the S&S 103 Hot Set Up Kit. It is a practical choice for servicing or rebuilding a compatible Twin Cam engine, backed by S&S Cycle's reputation for quality performance engine components. Features: Piston kit for 103 Hot Set Up Kit Includes forged pistons (unless otherwise noted), rings, wrist pins, and clips 3.875 standard bore Made in the USA