Thanks, I should've known that because 1 Candy Co. that I worked at and some European machinery that used a, " P I V." or "PVI" transmission that had a crank and a tach. on it, inside were 2 sets of pulleys with radial slots on both sides, then in the middle was a link belt about 20 links wide with side lugs that fit inside the radial slots, belt had fixed length, so as one was squeezed or opened up the out put r.p.m.'s would change. Some how I think that if such a unit small enough to be used on a Kart, it would be not heavy enough to hold up, and there is no way it could be manipulated on the track, we have seen M'cycle engines in the 125c.c. size try to use a std. bike tranny and shift while racing, NFG, won't even keep up with the slowest Sudam 125.