You know you can’t have both speed and acceleration out of the Rotax. For faster acceleration, go smaller on the clutch gear. There are 11 and 12 tooth sprockets. Going down to a 11 tooth on the clutch sprocket is going to change your top end from 72 to 61 mph at 13.5k using the same 79 on the axle. But off the line you should be pretty good.
Keep in mind that the Rotax isn’t going turn much more the 13.5 and have any power behind it. A shorter track is going to help you out.
LAD Specialties customer / tony kart / rotax / kt100