Hello,I was riding my 06 250ex yesterday and when I would open it up in 5th gear at 3/4 throttle it would start to sputter then stall out. After a few minutes it would start back up and run fine while I played around in the mud and on the trails. When I opened it up in 5th again it did the same thing,this happened twice. Do I need to clean the carb or is there a deeper issue? Thanx!

 

Sounds like it's not getting enough air. Check the filter AND the ports that lead into the airbox.

 

First thing I would check is the tank vent and make sure the fuel shut-off is on all the way.