I have a 2012.5 Electraglide Ultra Limited. I recently installed the Tmax tuner, Arlen Ness big sucker air cleaner and Rinehart 4" slip on mufflers. I had the cat completely cleaned out at the same time.
Ever since then, especially while the bike is warming up I have an odd sound coming from the exhaust. It almost sounds like heat shields cooling off but it's not, it's coming from the exhaust itself.
I have had a custom bike builder tell me it's actually reversion, or otherwise known as an echo of a sound wave travelling back up the pipe towards the head and then being forced back down the pipes on the next exhaust stroke. He says that when the CAT was cleaned out it left a bit empty sound chamber for reversion to start it's path back up towards the heads.

Anyone else heard of this? The shop that did the work claim they cannot hear the sound but anyone I've had listen to it says they also can hear it. It's kind of a weird tinging sound.
My next move is to possibly get the Rinehart slim line true duals that bolt up to the 4" slip ons.

 

Are you sure it's coming from the pipes? I got rid of my Ness Big Sucker because of the reversion sound coming from the intake tract. Like a little drummer in there tapping on a wooden drum. The open back AC lets all that sound out.

I went back to the stock housing with a K&N filter, noise gone.

 

This would be the easiest thing to check and I think Rockout is correct in his diagnois.

 

It's clearly coming from the exhaust. I actually ran into a guy this week who has done exactly the same work on his 2014 streetglide and he has the same noise as me although at a slightly lower audible level. He never noticed the sound until I pointed it out to him. He has different slip ons than me though.

 

Here are previous discussions of reversion

https://www.google.com/webhp?sourcei...aust+reversion