Great info. I will have to think about this... Also, I made a mistake, it's not a 250cc tank it's a 125cc. My bad. Well I still have my 2.5R (.15) motor and changed my gearing for higher acceleration. My final drive ratio is 11.24. I have superior acceleration but feel that my top end is sacrificing a little too much. So, I'm trying to maintain high acceleration while gaining top speed, which is why I'm looking for a bigger motor. Thoughts please.