My 13 year old daughter is just getting into riding and has moved up from a Sherco 2 speed auto to an old 80 fantic air cooled mono which was the lads. He was happy to just tazz about on this, but I think she is going to want to compete. I've looked at other small bikes and they seem as useless as this one so, as I have a 125 engine I thought I would slot it in. I've seen some reports of people doing this years ago to create a useful schoolboy mount, but no technical detail. Can anyone remember if, they used the 80 or 125 exhaust and air box. Anything else that would be helpful???