My 06 St. Bob does the same. It was even worse when I added the luggage rack. I verified bushings where good and everything was tight to no avail. I ended up adding rubber (used old inner tube) between the luggage rack and where it mounts to sissy bar and then used one wrap of electrical tape around rear mount point bushings. It is all good now and when wife rides passenger she isn't complaining about the buzzing on her back anymore.

 

Also this could be a sign of a much larger problem. There was a thread somewhere lately. The guy was having buzzing and rattling from the passenger seat, on lowrider i think, wife was complainin' (go figure right). Well it ended up being an motor mount was loose and causing this vibration. If you do go back to the dealer and they look at it might wanna see if they will check the motor mount.

 

I have the detachable on my RK. Installed it myself and does not vibrate. The installation kit fits numerous models and has parts for all of them so you have to install the correct thick and thin bushings, per the instructions, to get the correct fit. I have a whole bag of extra pieces left over when I finished. I would guess whoever installed it, didn't put in the correct number and or width bushings for your model bike.

 

My detachable sissy bar is good and snug. I switched one of the back clips for the HD locking clip. I wonder if the locking clip grips a bit tighter then the stock non-locking one.
I use to have problems getting the sissy bar off. Now I use 2 different seats and have to remove the sissy bar each time I take the stock SE seat off, which is at least once a week.
I now have no problems removing the sissy bar. I guess practice makes perfect.
Tom

 

I to have the vibration in the sissy bar, everything is tight and double checked, I think i will have the motor mounts checked and if not that see if they will replace the rubber mounts for the sissy bar. I wonder just how many people have this same probem?

 

Never had a rattle on two that I've owned, but here is another suggestion: The tape should work, but you can also add a thin washer to extend the docking hardware outward by a scooch, just enough to put tension on the side plates when they are clipped on. This should get rid of any slop.

 

Hmmmmmmmmmm, this idea sounds promising.

Actually, this sounds like a very good explanation as to why some of these might rattle. Since the dealer installed my before I picked up the bike, I was not aware there were various bushing, washers, ect. Might have to look into what they did with all there leftover parts and see if they have any other combinations of bushings.