If this has already been asked I apologize but I have done some searches and not been able to find what I want. I bought a 2006 CRF450 a couple months ago. It ran alright but did not seem to have the power I expected. I am coming off of a 2001 CR250 which I have drag raced against my 450 and the CR250 pulls it every time. I thought at first this was just because my CR has some modifications (SST pipe,v-force reed cage, uni air filter, projected tip spark plug, power valve spacer). I recently purchased a FMF mega bomb header, uni air filter and removed the backfire screen which did seem to help some but not enough to beat my CR. I believe all that is needed is to get the jetting correct but I am not the best at jetting four strokes so if someone has tried this combination or one similar to it on a 06' CRF450 I would greatly appreciate any input as to what settings they run at what altitudes. I still have the stock 168 main 42 pilot and the needle and pilot screw are stock as well. The altitude I ride at is about 2,500 feet.