Fits with OEM flywheels. Sprocket shaft has keyway, use 23985-56 key (MCS 517960). Taper is 8-1/2°. Shaft is 3.51" long from bearing shoulder to end of smalll thread. Use 24023-36 JIMS nut (MCS 978258) on flywheel side and use 24003-55 nut (MCS 518000) on sprocket side. JIMS shafts are precision machined in Camarillo, California from a special order steel. Each and every part is thoroughly inspected and after heat treating all threads go through a special process to make them withstand greater torque stress. All shafts are ground to a 16 micron finish or better, unless specified otherwise. All ground diameters are concentric to well within .0003", making truing and rebuilding quicker and with less effort. Note: Will not fit electric start Panhead models with the aluminum primary.

Fits: > 56-64 Big Twin with OEM flywheels