2004 XB12R Something is banging every time I hit a bump. The front isolator was worn out and I replaced it. Headers and muffler aren't broken. I've checked everything and can't find anything loose. Battery is strapped down. I did notice it happens when the rear tire hits a bump. To describe the feeling, it would be like someone lightly hitting the engine with a hammer. Any ideas on what else it could be? I'll send a pizza to anyone that leads me to a solution.