After last year's fiasco with multiple pinch-flats and strandings and poor quality "80cc" 2-stroke joke, which I threw in the trash, and following by a week-long attempt with 5-mile-pedalling to bus stop to ride to work (peak of gas prices) which was thwarted by a pickup colliding into front of bus and smooshing my ride and leaving me stranded again, I swore off bikes for good. A month later I was waxing philosophically about remembering only the good times the motorbike gave and not remembering the bad, but still swore them away, and many of you said you'd ride forever and I should get back on the horse again. Well, I'm BAAaaack! No way I'd ever go crummy two-stroke-joke with ridiculous carb setup again. So I got a 4-stroke rear mount kit from bicycle-engines.com and put it on a cheap Craigslist full-suspender in hopes of reducing pinch flats if the rear wheel could "give" a little. I laughed at the idea of having the entire heavy assembly held on solely by the rear axle. I've had enough flats and suffered with tire removal, but to have a flopping engine too?!?! So I grooved and welded the brackets to the rear drop-outs so the tire could come right out and the engine assembly could remain unchanged. Being rear suspended, I couldn't mount the front turnbuckles to the seatpost, so I welded in a length of flat steel to the front pivot of swing arm. I did three consecutive trips to work, totalling exactly 120 miles, and haven't gotten stranded yet! The engine can only be heard if I turn my head, minimal vibration, doesn't bog down nearly as much as the 2 stroke. I'm in the hills with constant grade changes. but I manage 10mph with pedalling on the steep stretches. 25mph most of the time, 35mph downhill. Once in the city's perfect flats, 30 mph. Each way of 20.0 miles takes exactly one hour. I fill up at gas station next to work, go home and back, round trip of 40.0 miles and hardly a drop left in tank....fillup is 93 cents and .40 gallons ....exactly 100.0 miles per gallon. Minor gripes, the two bearings in cover has severe flat spots, like been pounded on one point and dented race. No response from email to bicycle-engines.com. Hoped for warranty, but impatient to ride so went with it. Gearbox is louder than engine, but much quieter than anticipated. And throttle cable they sent was way too short. Would be fine for in-frame mount, but a foot and a half too short for the rear kit it came with. I choked when local bike shop charged me nearly $15 for cable and housing! And today the centrifugal clutch hangs up and stays engaged coming to a stop stalls restarts with wheel turning with each pull, like the return springs aren't pulling shoes back in. Maybe a teardown/lube in order. Ridiculous gripe....the center kickstand I ordered from them also... the mounting bolt was sticking out funny and threads were mauled in kickstand. I tried to grind the tip of bolt's threads to get back down to clean spot and my jaw dropped. Of all the ridiculous "China quality control" issues I've seen, this tops it. I wish I could actually show you guys/gals.....there are no threads. The "threads" do not actually thread. Meaning that each thread makes a single loop around and back to itself, without advancing up one pitch for each revolution. It's like a ring-shank nail!!! Unbelievable. Final mod will be to weld the front deraileur to keep it on the big ring and move the grip-shift for rear over to the left side (throttle and grip shift don't mesh, so currently only able to shift front gears which bites). Overall, I'm glad I listened to my heart and my fellow motorbikers here and got back on the horse!!!