You know I am thinking more and more that the simple small engines over the rear wheel is becoming more to my liking. The 22cc engine I have on the MB is pushing the bike along very well. It is compact and is very quiet, and I could add a longer pipe down away from me and get it more quiet. The only thing I would like is a better drive system, I am not fond of the friction drive. I just slips too much. It needs a larger drive wheel that would give more surface to drive with, but it also gives me too high a gear, so I need to use a drive system to slow the large wheel down. I was watching all the bikes go down the bike path today and with my complete release system I can use the bike path with the engine off, and with the extra weight being so small and no friction, no bother. I think a 2" drive wheel would be the best traction on the tire, so I need to find a way to drive it in a simple manner. Have fun, Dave