07 450r jetting

[coltrain65]

2007 450er
AC Racing Full exhaust
Uni filter with no lid
45 pilot
4th clip needle
160 main

only problem i have is when i am in high rpm at a constant speed it seems to sputter and want to die as soon as i go full throtle its find until i go constant again.

When i run
45 pilot
3rd clip needle
160 main
The sputter in high rpms is gone hower i now seem to bog on 1/4 to 1/2 throttle. i like the way it fells on the 4th clip a lot better, what do i need to do just continue to go up on the main i tried a 170 and it stayed the same, need some ideas thanks.

[450r07]

sounds like you need a smaller main does it act like it is flooding when you get to full throttle?

[sunco]

4th down from the top ? right

[coltrain65]

yes 4th from the top also tried the 5th and still sputtered at a constant speed.

[sunco]

i think mines a 165 4th clip down. no lid sparks pipe & hrc kit - running premium

[DnB_racing]

Carburetor troubleshooting is simple once the basic principles are known. The first step is to find where the engine is running poorly. It must be remembered that carburetor jetting is determined by the throttle position, not engine speed. If the engine is having troubles at low rpm (idle to 1/4 throttle), the pilot system or slide valve is the likely problem. If the engine has problems between 1/4 and 3/4 throttle, the jet needle and needle jet (most likely the jet needle) is likely the problem. If the engine is running poorly at 3/4 to full throttle, the main jet is the likely problem. So my question is does the quad act the same at all carburetor positions?

[DnB_racing]

Needle jet: Controls 1/4 to 3/4 throttle. You can tell the most when this is out of tune when you do holeshots. If your engine is bogging when you dump the clutch on a holeshot or you are riding at a constant 1/2 throttle and you engine is bogging then you need to move the c-clip up one notch (drops the needle making it leaner). If the engine is cutting out in these situations you need to move the c-clip down one notch (raises the needle making it richer). Setting the c-clip in the middle slot is a good place to start.