running like s**t

[exrider2002]

I have a 2002 400ex, elevation 500 feet, temperature 60, hmf slip on, k&n airfilter with precharger. I'm running a 185 keihn main jet (i thought this would be way to rich but i'm getting a nice light tan on the plug) 5 position on dynojet needle (also thought this would be to rich) 2.5 turns out on mixture screw stock(38) pilot.

At idle to 1/4 throttle the quad is running like crap. And the plug is black. After 1/4 throttle it clears up and the plug has a light tan color to it. The mixture screw and pilot work a idle to 1/4 throttle right. So if anything it should be running lean at the stock setting from idle to 1/4.

So does anybody have an idea what the problem might be:grr:

[thame2010]

dude, i dont know too much about jetting, but for what i'm reading, i'd say that your pilot jet is the problem, you may go with a #40 or #42 .. maybe..:D

[thame2010]

or maybe you should put a smaller main jet to compensate a bit... dude i really dont know.. better let the experts post

[thumper250x]

I had the same problem, i was running a 180 main with a stock 38 pilot. so i changed the pilot to a 42 and dropped the main jet down to a 158 and it idles perfect and runs a h*ll of a lot better. hope that helps

[thame2010]

WoW! I was right :devil: ..ExRiders: the best school :macho