400ex quitting at high speed ??

[t_vanness]

I have a 2001 400ex with curtis sparks timing advance key, re-jetted with 45 pilot 145 main, choke removed, snorkel removed, airbox lid off, and FMF power core 4 slip on. I am having a problem with it quitting after I run it wide open for awhile. I checked the plug color and it looks good, not running lean. When it quits I coast for a while in gear and it eventually re-fires. I would appreciate any ideas on whats up with it

145 jet seems awful small but what the hell do i know...:confused:

does it do this in any gear runnin it WFO or is it at the top of 5th??

is yoru airfilter always clean??

[cals400ex]

are you running keihin or dynojets? the stock main is a keihin 148 and there is no way in heck you should run a smaller jet than stock with mods on your bike unless your at high elevation levels.

[Doibugu2]

sounds to me like you might be overheating it. Your mj should be much bigger.

Check your oil, I wonder if it is black.

[Toadz400]

I agree with the other guys, it sounds like you are running lean considering the size of your MJ. The odd thing is my 400EX does that (quits at higher speeds) but that's because it's running very rich.

Are you using the Keihin jets or Dynojet? At 70-90 degree weather at 1000 feet elevation I run 155 MJ (no air box lid with a Big Gun slip-on) and it runs just perfect, not lean, not rich. That is with the Dynojets.

[t_vanness]

i am at 3000 + feet of elevation. The jet is a kehin main direct from honda. Also it only does it in fifth gear. I do believe my jetting is close because as I increase in elevation in the mountains I ride in, at the top of the mountains it acts kinda like the choke is on, being too rich. Air filter just cleaned also

[t_vanness]

also its a 155 main, my bad:blah:

[cals400ex]

i would take the carb apart and clean the heck out of it. you can use compressed air or carb cleaner.

[sickmojave]

I had a gas tank vent hose cause my mojave to do this. It was almost completely plugged. It would cause the tank to have a vacuum by the time I got to 5th gear. the motor would die and once it set just a few seconds it would crank and go till I held it open again.