A mate of mine fell of his banshee and the shee rolled into its side. After he rolled it, it would run ok for a bit but a lot of times when in 6th gear and sometimes in other gears while ridig it would just turn off and sometimes while revving it at idle it would make a popping noise, it also took much more kicks to get it started. He changed his spark plugs but still doing the same thing.
What could be the problem?