Well, I have to say, there is a solution to all your 250 2 stroke worries. I did the same thing with my wifes 85, when everyone was saying it can't be done bla bla bla. I've been building enough bikes to tell you it is easy. If you want to own a bike that runs just like a 250F, but is a 250 2 stroke, look no further. Take the pipe off, make a metal thin sheet or use a thin washer to fill the pipe fitting completely, where it hits the exhaust of the cylinder. Drill a hole exactly half of what the stock diameter is. Your bike will still have the same low end, so it will still have more low end than a 250F stock. But then the top end will just not rev, so the topend will be very very comparable to a 250F topend. You will be astonished at how easy it is to make a bike run just alike a 4 stroke, but still be reliable as a 2 stroke. My wifes CR85 is perfect now for her. It has more low end than stock, because I doubled the reeds, but with the pipe mod, it takes the top end (powerband) away. So now, I bet if you dyno it, it would be very comparable to a 4 stroke powerband. Very.
