My 400ex has a peculiar problem. After ridding for a while it will sputter and stall at anything more than idle or less than full wide open. When i shut it off and let it sit for a while it will start and run good for a while and then start doing it again.

I have a UNI, T-4 slip on and a dynojet kit and i'm running 146 main, 42 pilot 3.5 turns, and 4th clip on the needle.

I did notice some snow in my airbox, could it just be sucking in some water???

 

might be sucking in water, gets in your gas, dilutes it, making enjine stall? That might be the problem

 

Oic mabey i'll clean my filter and dump some fresh gas in and see what happens

 

That happened to me once. I found out that I had forgotten to turn the choke off.

 

I already took the choke off a while ago so that isn't the problem

 

I had pretty much the same problem about two weeks ago. I had to rejet (was running 138 Dynojet which was to lean to begin with and went up to a 146) seemed like a lean condition to me. So far I have not had the same problem. It is running pretty strong right now. I also put a little HEET in my gast tank to prevent things from freezing up. Maybe it was on the verge of freezing up espeicailly if you found snow in the air box/air filter