I just recently bought a stainless steel Dr. D exhaust for my 07 yz450f. When I was taking off my old exhaust, it had a clamp that held the header pipe and tail pipe together. When I went to go put the new exhaust on it the clamp wouldn't go tight enough to tighten on the header pipe and tail pipe. Does this Dr. D exhaust need a clamp to hold them together or is the fit tight enough I don't have to worry about anything? Thanks.