S&S Cycle 84-99 BT 4-1/8in Stroke Flywheel Assembly

This is the S&S Cycle 4-1/8 inch stroke flywheel assembly, designed to replace the original flywheels in 1984-1999 Harley-Davidson big twin engines, specifically for S&S 111" V111 applications. This assembly is a crucial component for your engine's rotating assembly, directly impacting its power delivery and potential for higher RPMs. It's a three-piece design where the pinion and sprocket shafts are forged directly into the flywheels, minimizing potential failure points.

The flywheels themselves are CNC machined from heat-treated, closed-die steel forgings. This process results in a material that's 114 percent stronger than the stock steel flywheels found in later models, giving you a more robust foundation for your engine build. The only joints in this assembly are where the 1.671 inch diameter connecting rod crankpin is pressed into the flywheels, a strong and reliable connection.

This assembly comes fully put together with heavy-duty S&S 7.667 inch connecting rods, featuring full-width wrist pin ends. It's also dynamically balanced, and the entire assembly is trued to less than .0005 inches of runout on the pinion and sprocket shaft bearing surfaces. This level of precision means the assembly is capable of handling higher RPMs safely, making it a solid choice for performance-oriented builds.