I have had this stutter in my bike ever since i received it from sea level. I live at about 4,500 ft and the bike has just been acting up. not too bad though. it's a used but almost new 07 wr450f. with all of the free mods. grey wire throttle stop bored exhaust you know. we thought that the stutter might be because of the jetting so we changed the main jet from 175 to a 160 we actually tried lots in between but it kept getting better everytime we changed them. so we finnally stopped at 160. we also changed the pilot jet to 48 i believe from 60. the bike is alot better with the newer jetting but still has that stutter at high RPMs. it just BUGS ME. some guys said it is a classic wr stutter. they said to remove the Throttle position sensor. TPS. so i took my bike apart and disconnected it.. IT RAN GREAT WITH NO STUTTER!!! It still has alot of power. but i hear that once you disconnect it you loose 20%. I would really like to reconnect it and adjust it so the stutter is gone and i get that final 20% power. I read the manual but some of it doesn't make anysense. when i start it to check if it's between. .58 and .78 volts does the coupler need to be connected? do i have to do it from behind the coupler? if so how in the world do you get behind it? there is a stock green mark on the TPS that is lined up so i really wonder how far off it is? I would really apreciate any light on this situation thanks!!