Ive got a vtx 1300 c that I got in August of last year, it now has started backfiring when I let off of it. They told me at the dealer it was a block off plate so I got one on the way. It has a dyno jet kit and vance and hines pipes, I took them off is there supposed to be a gasket other than the steel plates attached to the pipes. Im new to this any help would be appreciated. I also ordered felpro 60569 gaskets to put back on but I have no idea what the block off plates are they said they went on the head between the exhaust. Some kind of smog control.