I had an intermittent clacking sound coming from what sounded like the top end of my 09' SERG. Was at the dealer the other day and a guy showed me his 08 Ultra and said it was making a similar sound. Said it only happened when at a stop sign. He showed me where when the bike was idling with his heel on the floorboard and hie toe on the brake his heel would make the floorboard insert shake back and forth causing an identical sound. His comment was to check other things first before assuming the engine was the problem. I checked my inserts but that was not the problem.
Today I found the noise that sounded exactly like a valve train or piston slapping sound. I put Kuryahkin passenger floorboards on my bike. When the bike is idling with the front brake on, the bike shook enough to cause the floorboards to shake in the brackets causing this sound. The funny thing was that when my bike was making that noise, you could lean forward and focus your hearing in front of the gas tank and it sounded like the noise was coming from the top of the front cylinder. The moral of the story is that these "engine noises" could quite possibly be something entirely different. T.