Sprocket shaft has keyway, use 23985-12 key (MCS 517945). Use 7974 nut (MCS 981184) on flywheel 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.
