I'm not exactly sure how it happened but I think it was from casing a double. The 2" pipe that is welded to the larger 5" canister broke in a complete circle. The clamp that is towards the engine may have vibrated loose making the bolt a pivot area and the impact of the jump may have caused stress on the pipe.......at least that is what i'm telling myself . anyone experience anything like this? Has anyone put a spark arrester on their stock pipe (promoto billit)? was it easy to do? did ya like it?