I know that this is probably the most common question on this forum, for that I am sorry. I would love the input of both parents and teens both on this one. My boy is 12. I started him at 10 on a CRF 80 which he did OK on, but out grew it it 14 months, so last November I got a good deal on a new 2yr old CRF 100. As everybody knows these are fairly tame. Most of our riding is relatively flat trails, some hills, but nothing too technical, some woods here and their and some backyard motocross. He is 5'2 and weighs 120 lbs. I have changed the gearing, exhaust and jetting in attempt to make it more suitable for long distance two track, which it did somewhat. He skill and confidence has improved to the point where the 100 is not fast enough any more. We did 120 miles of trails in less then 4 hours with him leading. My DRZ spedo was showing speeds as high 52 mph . That was FUN. Should I do a BBR or Engines only 120 kit and a carb ($300-$500) or replace the bike and with what? Or should I have my head examined?