GOOD RULE OF THUMB
Running rich can rob hp also. Check your spark plug color. Run the bike at idle then shut it off and check it (Pilot jet), hold the throttle to mid throttle for about 10 secs and shut it off instantly and check it (Needle position), then hold it WOT (preferably while riding it) and shut it off and cost to a stop (Main jet). Your plug reading should be a nice tan/brown looking color for the best performance on each check. It is time consuming but the best way to make sure your bike is dialed in CORRECTLY all throughout the powerband. Adjust your jets according to what your plug is telling you
White plug needs more fuel ( bigger jet )
Tan plug good ( adjustment needed )
Black to much fuel ( smaller jet )
"06" YFZ450 jet kit and zip tie mod, cam mod
"06" Raptor 350 stock
"06" predator 90 stock