When I pull up to a stop and rev the motor a bit because, well because it sounds cool and I like it, but from time to time when I do this, it sounds like somebody takes a wrench and slaps the side of the engine housing with a loud CLANK. Doesn't do it every time, but probably 4-6 times out of 10. I took it in for service and told them about it and they could not replicate the event. After that visit, it seems to only do it 2-3 times out of 10 now, but still does it. Has anyone ever had this happen? 2014 Electra Glide Ultra Classic, Screaming Eagle Street Cannons, Tuner, and Air Intake.