S&S Cycle 99-06 BT 4-5/8in Stroke Flywheel Assembly W/O Sprocket Shaft Bearing

S&S Cycle is well-known for building powerful engine components that stand up to demanding use. This flywheel assembly is a prime example, designed to replace the original flywheels in your S&S T143 engine for 1999-2006 Harley-Davidson big twins. It features a 4-5/8 inch stroke and an 8-1/2 inch diameter, offering a solid foundation for your engine's power delivery.

What sets this assembly apart is its construction. The flywheels are CNC machined from heat-treated, closed die steel forgings, making them 114 percent stronger than stock steel flywheels. This robust build, combined with the fact that the pinion and sprocket shafts are forged as part of the flywheel itself, contributes to a stronger, more reliable assembly. The entire unit is trued to less than .0005" runout on the pinion and sprocket shaft bearing surfaces, which is crucial for higher RPM operation and full compatibility with gear drive cams. It comes fully assembled with S&S heavy-duty 7.800" connecting rods, featuring full-width wrist pin ends and dynamic balancing for smooth operation.

This is a three-piece design where the only joints are where the 1.671" diameter connecting rod crankpin is pressed into the flywheels. Note that the sprocket shaft does not have a stock-style bearing race pressed on; this assembly is intended for crankcases equipped with a Timken sprocket shaft bearing. The pinion shaft is designed to drive the balancer chain.