If you haven't figured it out already, this is the "DON'T DO THIS" thread. My latest mess up/learning experience is the Ebay muffler I purchased a while back. New, yes. Shiny flawless chrome, yes. Anything approaching the ability to "muffle"? NOPE. It's basically a straight pipe, with no perforations, and a sort of teaspoon-looking deflector welded in the middle of it. (see illustration) Not too sure what the point is, because it doesn't quiet anything down appreciably and it doesn't improve the quality of the sound. But if you just want something for looks alone, then it works.
I ended up getting a comically large HD muffler for $18 shipped, (a stocker from one of their 1340cc baggers) and it will fit barely lengthwise, but it WILL reduce the noise and it WON'T restrict. So, win-win. It has a real baffle and being that it's rated to handle a 670cc jug, the little 250 will probably not even get it hot!
Amazingly, the weight difference isn't too much!
No one ever said this was going to be pretty.