I bought this quad about two weeks ago and tore it down and found a few problems fist thing it ben rolled. all that stuff has ben fixed but,this it only dos it at iddle and through low rpm it seems like a miss fire but with the air box open sounds like a back fire through carb from cylinder #1.could it be a vacuum leak or timing or valves?

 

or a loose plug wire? You mentioned that it was rolled. Things come loose

 

i replaced the plugs and i thing that wire did separated from the metal connector.and also iddles vary low and iddle adjuster is turd all the way