First i want to say thank you all who have replied to anything i posted asking questions about a 2003 yz450f. I have finally completed the whole valves train and cylinder head rebuild. I did piston and rings replaced the timing chain thanks to greyracers handy sticky. Which by the way the torx number is a 30 not a 27 for removing the stator. Also did the valve train new seats springs cotters clean up the valves and head nicely seemed to seat just fun everything went well. I am running stage 1 hotcams which i am starting to think is part of my problem. I did the clearance adjustment and that seemed fine after it was done. Sooo it started up 2 kicks sounded good and everything. I took it for a test and it seems when you get to between 1/4 and 1/2 throttle it just starts bogging real bad and it is steady if you stay in that rev. But once you open it up it clears right out and throws you back on one wheel if you arent prepared. Which is nice in its own way, but i ride the woods alot and one i know its not right and two its where i need the power for hill climbing. I had bought an fmf jet kit, which i think was a waste. At the moment i am using the jet needle they give you in the kit, with the clip second from the top. And i am running the main stock 165 with a 40 pilot. I have no idea which way to go, i called dyno jet and asked them on there jet comparisons to the keihin jets and they where no help and werent able to tell me if there dj155 is leaner or richer than a keihin stock 165. So anyone that can help me figure out all this i would appreciate it.