517989 Sprocket shaft, special application

This MCS sprocket shaft is a specialized component designed for custom engine builds where you are running 1972 to early 1981 Big Twin flywheels inside 1956 to 1964 Big Twin crankcases. It features a no-keyway design, making it essential for specific high-performance or custom configurations that deviate from the standard setup. When you are mixing and matching era-specific bottom end components, precision is everything, and this shaft provides the necessary interface to keep your drivetrain aligned. It replaces OEM part 517989 and is built to withstand the rigors of a vintage Big Twin motor. Whether you are restoring a classic or building a custom chopper with a hybrid engine, this shaft ensures a proper fit for your sprocket assembly.