Sorry i haven’t been on in a while, to answer the most recent question about jets in the stock carb, we ditched that carb and went to a mikuni vm 22, however after hours of tuning it an rejetting , these motors just don’t have enough low end air movement to correctly pull the fuel for idle and early part of needle circuit resulting in a lean bog, I just purchased a 20mm aft carb from tbparts.com and some jets to correct this issue.
The next question about stock cdi limiter, yes this was an issue, we went with a cheap after market eBay setup, one of the no rev limit deals, I recommend getting the one with adjustable timing as the timing curves are close but not exact to the stock cdi, VERY IMPORTANT- make sure the cdi you buy is a DC cdi box, do not buy a AC cdi box as it could damage your system. The 16-19’s are different than earlier models so don’t buy a cdi listed for one of these earlier models. We also increased the front sprocket size, going one tooth up in front is like going down three in the rear I believe, I would only go up one or two teeth in the front and see how that does. We only went up for one now but have clean up to a 17tooth front sprocket that I haven’t tried yet because you will need a longer chain and I’m waiting for ours to wear out.
We also have no chance of catching the top two dogs in My sons class as their apex 90’s are built to the moon and and honestly should have a class of their own, however 3rd through 7th place is a always good and fun battle to watch. FYI we are the only four stroke and the rest are two strokes. If the two stroke is a stock deal and your bike is properly setup you can beat them. All comes down to the rider as well.