ive seen that some people have drilled 3 or 4 holes in this "second baffle"Are we referring to the back of the muffler?

 

For me, I kept drilling into the exhaust, past the first 1/2" hole that I initially drilled.

My 1/2" bit wouldn't reach the 2nd baffle, so I had to get an extended bit, but the largest they had was 3/8". Same procedure, though - start up the bike, insert the drill up the tail pipe, and drill through whatever gets in your way.

Same incremental increase in the sound level as drilling the 1st baffle, but nowhere near the level of an after-market exhaust. There was a slight change to the tone, as well ... a sharper attack, or pop, but it wasn't bad at all.

 

what about enlarging the exhaust outlet?makin it about 3/4 or so?

 

I saw some pics where someone did something along those lines - they replaced the 1/2" pipe with a 3/4" pipe. It involved tearing apart the whole muffler and rebuilding it with the large pipe ... definitely more involved than attacking it with an electric drill.

I've contemplated drilling a few smaller holes around the outside of the 1/2" pipe, but I never heard of anyone doing that. Not knowing what was on the inside, it would be hard to guess what the results might be. (I suppose that since I now have a Big Gun exhaust, I could always sacrifice my stock pipe in the name of research.)

Alternatively, if a series of holes around the 1/2" pipe turned out to be catastrophic, you could always drill out a fender washer and epoxy it over top to cover the holes.

 

I drilled about 12 1/8 holes in a cirle around the opening in the exhaust and everything went alright.