400ex craping out on me

[Eddiesanders250]

im having trouble with my 400Ex. Im not shure what the problem is i think that the main jet may have dirt on it. it idles fine and when your low in the powerband it works fine. But when i get higher into it it just craps out. It just has no power, it is like starving for gas or something. Any help would be nice if you have an idea what the problem may be, im supposed to be going to the coast this weekend to ride and i dont know if a i am going to be able to:(

[2001400exrider]

mine did that same thing last weekend. turns out it was either the spark plug cap not on right or it was the dirt in the bottom of my float bowl in my carb. but i blew all that dirt out that might have been clogging the main jet...and now she runs perfect:D