03 400ex sputters

[my99ram]

I'm at about 150' above sea level and temps from 75-85 when riding.
I have a 03 400ex, t4 slip on, K&N filter without lid,42 slow and 170 main with needle clip in 4th position(4th starting from the top) and when I'm just riding at a steady speed it sputters like theres a miss,that mean I'm running to rich?should i put the clip in the stock 3rd position?
my air screw is about 3 turns out

[300exBorg]

That's pretty rich for the mods you've listed. Check what your plug looks like and take it from there. I would think it's safe to say you're running rich. I was running a 165 with just a full exhaust and uni filter and was way too rich. Of course our locations differ so it won't be the same but I def. think it's safe to say you're rich. I would wait until the more "experienced" riders chime in before you do anything though.

[my99ram]

Originally posted by my99ram
I'm at about 150' above sea level and temps from 75-85 when riding.
I have a 03 400ex, t4 slip on, K&N filter without lid,42 slow and 170 main with needle clip in 4th position(4th starting from the top) and when I'm just riding at a steady speed it sputters like theres a miss,that mean I'm running to rich?should i put the clip in the stock 3rd position?
my air screw is about 3 turns out
air screw is 2 turns out and clip in 3rd position and runs alittle better.

[CJM]

Pull the plug. Your too rich imho.

[JOHNDOE83]

if it revs out all the way just fine then your main jet is good, what you described is deffinetly to rich in the needle area.

3rd notch is standard, you may need 2nd notch and if you havent removed your choke a 42 pilot may be to much.

sounds like your getting it closer atleast.

[01 400EXer]

You are running rich and I was going to reccomend putting the clip back to the 3rd position and drop the main down to a 160-165. Put a new plug in when you do this to see what she looks like after you run it a little. I have also figured out with my 400 that when the weather changes from season to season I am able to use the same jetting, but I just change the air box lid. I have one midified with holes to run in the summer time when the air is dense and a stock unmodified one I put on when the air gets cooler. This seems to work well for me and my 400 humder lets me know when I need to do something because it will act a little different and cough sometimes and at that time I know I need to change my lid. Just my .02.

[erik420]

I have similar mods and im at 160 main 42 pilot.

[01 400EXer]

I am running a 158 or a 160 main and a 42 pilot jet. Can't remember what I settled on since I have not had to change in forever. I have a uni filer, HMF slip on and a drilled air box lid.