400ex hiccups and dies

[wheelman]

Hey guys, I'm trying to fix a problem with my 1999 400ex. When I start it up, it runs real rough and makes this coughing sound and wants to die if I don't give it a good amount of gas. It seems to run better when warm but still exhibits the same symptoms when its warmed up too. Anyway since I've had it, I've changed the oil, I've tried cleaning the carb, it has new stabilized gas in it, and I just adjusted the valves on it this weekend. Still the problem remains and I don't know what to check next. Please take a look at my video to see the problem I'm having and let me know if you have any suggestions on what else to try.

http://www.youtube.com/watch?v=_JZ4jyHOwzQ

[01boneless]

sounds like its starving for gas the jetting shouldent be off since it looks to be stock take off the tank petcok and clean that little screen.

[DnB_racing]

also make sure some critters haven't made a home in your snorkel,

[AtvKid4Eva]

Make sure the air box boot didn't falloff the carb. Happens a lot lol.

[Stickman400]

I'd check the boot on the airbox side too. I just had that happen to me yesteday. I jumped my tabletop and after I landed I had no throttle past 1/2. So I went back to the shop and took the seat off and sure enough the boot wasn't even attached.