OK, I am sure this has been asked time and time again on this forum- but I can't find exactly what I am looking for. Here's the deal: Son is 7 1/2, weighs 80lbs (future linebacker), 4' 4" tall with about a 23" inseam. He is dwarfing his little CRF50 and it's to the point where it isn't safe. He rides it hard, but has never really gotten the shifting thing down- usually just leaves it in 2nd and revs the crap out of it. He has been riding this bike since he was 3yo. I want something that will last the next 2 years. We ride everything- tracks, trails in Northern CA. Green sticker is a huge plus so we can improve his riding during the "off season" at the local state parks. The problem is that I believe this will limit him to heavy, poor performing, trail bikes instead of a performance bike like a KTM 2 stroke. He is not ready for a clutch yet- so this needs to be factored in... Any thoughts, input, or feedback is appreciated.