Unfortunately in our area they are sticking to the same rules as AMA Pro Racing. My local area is not AMA sanctioned, so they have their own set of rules.. believe me, they are sick and tired of hearing me talk about two-strokes!!

So to answer your question, here the 250F races the 125cc two-stroke, except that in the class you can also race a 144cc two-stroke, which almost negates the 125... then the 250 two stroke races against the 450F four-stroke.
I didn't want to get a 144cc because of a few reasons, but mainly because I'm trying to get everyone involved in racing 125's, which I think are a great transition between the mini ranks and the big bikes. Plus last year I got our race organization to add a 125cc two-stroke class... if I got a bike that didn't fit in that class I'd be... well let's just say that I wouldn't be very popular on race day!!
