This 4-3/8" stroke 8-1/2" diameter flywheel assembly replaces the original flywheels in 2003-'06 HD® internally balanced big twin engines, increasing the stroke from 4" to 4-3/8". Sprocket shaft does not have a stock style bearing race pressed on.

• Assembly is trued to less than .0005" runout on pinion and sprocket shaft bearing surfaces, making them capable of higher rpm and fully compatible with gear drive cams
• Flywheel assembly is three piece design
• Flywheels are CNC machined from heat-treated, closed die, steel forgings, which are 114 percent stronger than late style stock steel flywheels
• Fully assembled with premium quaility S&S® heavy duty 7.667" connecting rods, with full width wrist pin ends, and dynamically balanced
• Pinion and sprocket shafts are forged as part of the flywheel
• Pinion shaft has sprocket to drive balancer chain
• The only joints in the assembly are where the 1.671" diameter connecting rod crankpin is pressed into the flywheels
• This flywheel assembly is for crankcases with Timken® sprocket shaft bearing