This type of thing has been done a million types, but why wouldn't I take pictures of the efforts. Building decent Sportsters as cheap as possible is as popular as ever. Here's my cousin's 883 Iron. He got it at an insurance auction. Someone else had chopped the rear fender and struts and then wrecked it. My cousin painted it and swapped most of the bent pieces with swapmeet take-off. These pipes are stock off a Sportster 48, I think. Anyway they are too quiet and he didn't want to drop five bills on new aftermarket pipes, so gutting the baffle seemed worth a shot.
The inside of the mufflers look like this. Tube in the middle and flatish surface connecting it to the outside of the muffler.
Step one: Drill as many 1/2 inch holes as possible as close together as possible in the flat surface
Wear safety glasses, my cousin refuses to.
It should look something like this.
Step two: Cut anything left between the holes out with a dremel or die grinder. Seriously, wear gloves and earplugs on this one.
Step three: Pull out the metal tube of the baffle.
Pull out the nasty fiberglass packing, too.
It should look about like this one when you're done. Don't forget to do the other one.
It should sound like this when you're done.