Savage mufflers appear to be prone to chirping.  My used 2001 began doing it shortly after I bought it.  

I believe something comes loose internally due to rust. I'm not sure if you can get into it to fix it.

The best solution is to replace it.  The preferred replacement on this site is to replace it with a Harley Dyna muffler.  They are available cheap as used take-offs.  The swap is pretty simple.  Mine bolted up fine without needing adapters.  I did only use one of the mounting holes on the muffler bracket, instead of both holes.  If you get a dyna with the baffle plate still in it, they are a little louder than stock, but not obnoxious.  They are also well-made with good chrome and no packing to burn out.

There is a good discussion/tutorial in the tech section.

Adding link to Dyna thread.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1298689417

Dave wrote on 06/05/13 at 09:23:08:


Hey now, while you haven't ridden with me, you have heard my stock S40 muffler before.    And, after almost 6 years and 21000 miles, it definitely sounds like my dad's last Super Beetle.

The one in the video is almost exactly what it sounds like so I'm guessing that's normal for a stock muffler.

That sounds like mine did before i got the Dyna. soooo much better now

savagester,
Just the way my 2007 S40 sounded. And I agree, the sound reminded me on my 1966 Bug. The Savage has a better heater, though.

Good hunting