This 4-1/8" stroke 8-1/2" diameter flywheel assembly replaces the original flywheels in S&S® 111" V111 engines for 1984-99 HD® big twins. Flywheel assembly is three piece design. Pinion and sprocket shafts are forged as part of the flywheel. The only joints in the assembly are where the 1.671" diameter connecting rod crankpin is pressed into the flywheels.