So, I traded my sons xr100 for a 2001 kx100. He hates it! We need to figure out how to tune the power band down lower. We would like a little bit more response on the bottom without having to rev out just to get going. Its got an fmf exhaust system. I love the bike! With a little whipping, it just screams and pulls hard! Shouldda got my son a 4 stroke,, but this is what we have,, trying to make it work.