I recently purchased a 1987 (could be 1986) yamaha TT-225 trail/dirt bike.
It's extremely loud, I'm taking steps to make the thing easier to live with...
I'm changing the oil, using 91 octane fuel (instead of 85), going to run a fuel additive for the next few times i fill up, and now i'm also looking at purchasing an aftermarket muffler/exhaust system.

my question is: what exhaust systems, or mufflers can i purchase that will reduce the noise, and make the bike sound better (right now, I'm pretty sure even a new stock one would do just fine)... Where can i purchase these items from?

I don't know much about motorcycles, so i don't know what parts would be compatible with my bike. I know that car parts might say that they are for a certain model, but will work with others, this is what i don't know with motorcycles, so I'm asking.

again, the bike is a 1987 (could be 1986) Yamaha TT-225.