Well, been riding for more than a month now. Very fun! I use it all the time, rarely get in my truck. I ended up simplifying the engine mount way down, and have had no problems other than occasional chain tension adjustments. I need to find a cleaner way to change oil, preferably with a siphon to suck out the dirty oil. Staton recommends just lying the bike on its side, but oil gets on everything. The bike goes about 27 mph flat out, and I am fine with that (I have the Robin Subaru EH035 4 stroke). It definitely helps to pedal on takeoff to spare the centrifugal clutch from whining so much. You can just throttle from a stop if you want, as I had to do after I discovered my rear derailleur was misadjusted, my chain got jammed in the frame, and I fell right on my helmeted head (I was standing still). Oh well. Only pride and right knee were injured.
I find I can coast a great deal of the time after building speed, which is nice because motor lapses into idle mode and is super quiet.
All in all, a blast to ride, and very useful vehicle.