Billet Clutch Housing CNC machined from 7075 T6 aircraft grade aluminum. With this new billet offering, all limitations of engine size and RPM limits on the regular version of the HD Auto Clutch Kit are removed. This HD Auto Clutch Kit can now effectively be used on all large displacement engines such as our 108 or 117cc kits as well as other brand bore kits (119cc, 124cc, etc). Inner rotors can also be used.