Hi, Ive been riding motor cycles since I was about 12, Minibikes from age 7, I'm 50 now. First bike was a Honda SL 100 enduro," Dual sport" to the younger crowd. And Ive had some damn fast stuff too through the years. Anyway, point being I know a little about bikes and what they are made of. This little bobber (Dong Fang 250 RTB) has a OHV 229cc 5 speed ATV engine. The reason I say ATV engine is it is very close ratio, geared way to low for a street unitized powerplant. After some math and seat of the pants figuring I pulled those useless stock sprockets off (must change final ratios) and settled on a 15 tooth front sprocket, and 38 tooth rear. A 16 tooth front sprocket made the gearing a little to tall. If I weighed 100 lbs I would have kept the 16 tooth. But being 250 and 6'3 I needed the 15 tooth up front instead. You will have to modify the front sprocket cover to accommodate the larger than stock front sprocket. I modded mine with a right angle grinder and a steady hand. Then as said put a 38 tooth out back. My chain did not need the length changed. That was a pleasant surprise. Now the Bobber can be used on a country 2 lane highway without eccessive revs or getting ran over because you can't go above 45 mph. Now, next important issue for most people is power. The Dong Fang 250 bobber has a 229cc OHV design. With the little stock carb that it comes with my seat of the pants Dyno says its only putting out 12 HP, 14 HP tops. That's because of the ancient OHV (over head valve) design engine. Should have been OHC (over head cam). Much better HP per cc. But in these engines the OHV is more durable than the racier OHC design. That's probably why you see 90 million motorcycles with these same exact powerplants in India and other parts of Asia and lets not forget Central & South America. Now What is good about this machine. Once broke in and necessary mods done, This thing rides rock solid and unshakable. It will inspire confidence in corners as well as going straight down the road. I very seldom slow up much before entering a corner it corners so good. IMO because of the flat track racer layout of the frame. Only a real Dumb Dumb can wreck this bike IMHO Next, The brakes are great too. The fairly light weight and big tires for the bikes size make the single disc front and rear practically throw you over the handlebars (stops on a dime). Now for the hard numbers after the necessary sprocket changes. It will cruise about 55 mph all day long. I can reach 70 mph (without headwind) with my big tall butt on it. A smaller person would fare even better on this bike. The acceleration is acceptable also with this gearing. Good strong pull for its size. Now for the last number someone may be concerned with that would buy a small machine such as this. With this gearing it gets 80 mpg at 48-52 mph in rolling hills. Mileage checked with two other vehicles. So this is confirmed, yes 80 MPG ! This is why I won't put a bigger carb or rejet it now Oh, And last but not least I can ride with a buddy with a $30,000 Harley or whatever and the Chinese Dong Fang Bobber gets all the attention at gatherings. Go Figure , But I eat it up ! I know this was a long post but I hope I may have answered some questions about this bike that there really is not that much meaningful info on. Feedback or alternate opinions are certainly welcome. Cheers