My Dyna muffler got really loud halfway to work this morning.  It's loud!  

It sounds great and runs better, but it's too loud for me.  Of course, there is also a little extra snap, crackle, and pop on deceleration.  

I know mine is pre-cat version (65747-94).  I think there was a restrictor plate of some sort at the head of the muffler, but I haven't had it off in years and don't remember exactly what was there.  I assume that thing must have broken loose or disintegrated because it basically sounds like a straight pipe.

Can anyone confirm this?  Any pictures?

It's not a big deal.  I have a couple of spares at my shop and I'll get a look at it at some point.  I'm just trying to make sense of what I had because the pipe is still solid and the tail end of the pipe is still intact.

supposedly, it's a freeze plug about half way down

The DYNA mufflers eventually burn out the core.  I am not sure if they do that on Harleys - but they do on the Savage over time.  If you have ever ridden behind a Savage with a DYNA muffler at night - you can see a bright orange glow from inside the muffler.....that core gets really hot.

I have a tool I made so you can use to drill out the old core on each end and remove it, and some perforated pipe if you want to install a new core.  The tool is basically and drill extension that allows you to use a hole saw to cut out the old core.  You would have to weld in the barrier inside the core.....then you could weld or bolt the new core inside.

Or......I believe I have a good DYNA up on a shelf I could sell you.

So I made it over to my shop yesterday and found my spare pipes.  Turns out I had four of them.  I remember snagging a set on craigslist a few years back, but I don't remember buying the other set!  lol

The bike runs much smoother now and it has proper low-end power now.  And it's very quiet now.  

I'm convinced that it's actually quieter than the old dyna before it blew the plug out.  I suspect that it may have been previously modified.  I thought there were a few holes in my old dyna muffler.   Below is a picture of a common HD "make more noise" mod.  Maybe I'll experiment with the mod down the road.  


Common HD mod.

https://www.hdforums.com/how-tos/a/harley-davidson-dyna-glide-how-to-remove-s...