I got a 400ex and it wont stay on unless it is set on really high idle,
I changed the spark plug,changed the oil and oil filter, cleaned air filter. Could it be one of the jets are clogged in my carb!

 

well dude from the looks of your bike it seems u take good care of it so the problem is not from misuse. a couple weekends ago my buddy's recon acted the same way and his carb was just dirty. i kno they are 2 totally different bikes but the symptoms are the same. by the way, is that pipe a supertrapp? it looks incredibly loud.

 

Yeah it is a superrtrap and it is incredibly loud!!

 

another thing you might want to check is to see if your hose going from your carb to your motor is on all the way, could cause a lil un nesicary air to get in there, mine did it once
-Wreckless

 

which hose because i only have one connecting carb to gas tank , there is 1 overflow on bottom,, take pic possibly of which hose and where it goes

 

i am talking about the tube that is clamped onto your carb that goes into your intake of your engine, look at the carb right under the right side of the gas tank, it has a hose clamp on it, make sure that hose is butt up against the carb
-wreckless