Huge Studder At 1/4+ throttle

[sandmanracer]

I've got a '04 TRX 450R, HRC kit and White BRothers E2 pipe. Currently stock pilot needle 3rd position from the top, 185 main. I run at sea level. The plug looks kinda rich, its's dark brown on the porcelain, and black on the threads. In order to get it to stop studdering I have to slip the clutch and get it to a high RPM, they it hauls. I figured it was clip position but I dropped one clip position from the middle and it made no change. Could my main be too rich?

[Z-135]

I would drop your main to a 170 or 175.

[400exrider707]

Your having the same problem that my buddy had with his. You need to drop that needle clip all the way down. He did this and it was still too lean. He ended up going with the HRC needle and he is on the bottom clip of that! That is the only way his would run good. If its studdering at 1/4 there is no need to change your main, althought it does sound a tad rich. Also bump your pilot up to a 50 which will help tremendously with that lower end studder and also aid in starting.:macho

[sandmanracer]

I dropped the main to a 172 from the 185, I also went one clip leaner on the needle, it ran like an Ape on Roids. Just for fun, I went back to the stock needle settings and liked that the best, it mellowed out the midrange. So, as it turns out I was just WAY to rich on the top, thanks for the help.