I was wondering if anyone has tried this and if so was successful. I realize that the 250r is water cooled but I thought that since I had a 300ex already that retro-fitting a smaller sized 250r motor might be possible.

 

Um that would suck dude, a 250R motor has too much power for the little 300ex chassis and Y would you want to take the motor out of one of the best handling quads in the world to put into a lesser frame? It would most likely be nonstop wheelies and too much power! 300ex's are good and all but I know I wouldnt want anything to do with this creation.

 

If you have a 250r motor handy and no 250r frame I guess its worth a try, just be prepared to have not so good top speed handling.

 

Man, if you have a 250r motor just laying around and are looking for a frame to put it in, you better not tell anyone where you live. Why do you want to put it in a 300ex frame? I am sure that it can be done but why? Screw putting it in the 300ex frame put it in a 400ex frame. At least it is similar to a 250r frame. I know that it can be done too. I have seen a 400ex with a 250r motor in it. It looks kind of funny because the 250r motor is so small. There is a lot of extra space in the frame.

Fourtracker14

 

That's not a bad idea. The 300EX frame is way too short though. The 250R's powerful motor would never let the front tires touch the ground. It would be like riding an ATC250R. The conversion wouldn't be a good one unless you were willing to sink around $3,000 in suspension. To make the quad ridable, you would need a +2(at least)swingarm, a arms, axle, shocks, and more than likely a steering stabilizer. But once you did all this, you would probably have a good flying machine. The EX jumps really good, and the R motor would give it the power to spin the tires wherever you wanted. You could make it work... But be prepared to spend some money!

Buying a rolling 250R frame would be much cheaper/easier in the long run though.