My son Matthew just turned 12 years old, and rides Mini Jr. He is a big kid. Probably 5'4 and 145 lbs. Just out growing an 85. I don't want to hassle with building a supermini. I thought I would move him to a 125 after all the series races end in September. Today he rode a 250F for the first time on a big bike. Took some slow laps and by the time he was done was jumping everything he does on his 85 and looking more comfortable on it. Now I am wondering......mess with a 125, a bike without a class, or just go 250F? He is a smooth rider, so I now I am thinking maybe 250F. Suggestions??