Motor cutting out

[flex_119]

Guys need help bad. 05 400ex cutting out and sometimes dying after hitting Jumps/Rough bumps at high throttle applications. The bike has hmf slip on, outerwears airbox cover and is jetted. Don't know what size jets though. Runs fine flat out in all gears, and also runs fine in wheelies from slow 1st gear through full throttle 4th gear. Any help would be great.

[JKD03]

I have the same problem when i hit top speed and then let off the throttle, it cuts out feels like its running out of gas but its not i was wondering the same thing

[dalejiw25]

Has either of these two bikes ever been in the same event together with some possible close contact ??? If so you must contact the other bikes in the event and see if they have the same symptoms. If They do this could be a nasty virus that must be stopped in our lifetime. Please keep us informed....

[matt14c]

Check to make sure the two grounds are tight against the frame. You may want to check your plug also. Check to make sure your fuel line isnt pinched and check your carb to make sure the float is working.