I have seen and driven a Rotax shifter motor with 6 gears. It was quite a few years ago at Moran. The guy had it on a Tonykart. I am pretty sure that it had electric start and a rave valve like a Rotax kart motor . It wasnt as fast as a Stock Honda but pretty close. I have seen another one on Craigs list a while back as well. maybee the same kart … So they do exist.