Big Twin cam gear. Undersize (black)

Black, undersize. Crimp-on installation on the camshaft. Used to correct backlash (free play) between the cam gear (on the cam) and the pinion gear (the smaller drive gear). Too much backlash will result in clicking, not enough backlash will result in a 'whining' sound. To correct backlash you can either use smaller or larger pinion gears or smaller or larger Andrews cam gears.