when I first installed this sytem on my whizzer ambassador with a 212....it snapped the shaft we had turned down to fit the 12mm bearings that were in the jackshaft area stock......that happened again a few months later and now we put a bigger jackshaft mount on for 5/8 shaft....you'ld be scared by what it did when it broke just idling both times... a guard is a good idea I think. Im having an alum one made