You need to give a little more info. What was the exhaust that was on the bike? 4 into 2? 4 into 1? stock? Straight? You can find universal mufflers easy enough but are the pipes really set up so you can just clamp a muffler on the end?
Regardless the easiest way to see some different types is to simply type universal motorcycle muffler into ebay and check out what you see. Know the pipe size before you check but if it's simply something to quit the bike down a bit you can find it there.