Fits: 1984-'16 HD® big twins 4 1/8 bore. Stock or S&S® heads. Piston kits include set of pistons, rings, wristpins, and clips
S&S 41/8" pistons are machined to such close tolerances that it is not necessary to measure the piston. Additionally, the low friction coating on the piston skirt makes taking
measurements very difficult. Therefore, hone cylinders to nominal diameter +/- 0.0005" for correct clearance.