Drilling out the ends of the stock slipons should be ok, especially on the late model stock exhausts. That's what American Custom Exhaust does; they sell you a drilled-out stock slip-on.

It's ok for the short term, however, getting a complete new exhaust is the best way to go. I found that out; went through four different setups before I ended up with something I'm happy with.

 

Drilling holes won't have any negative affect on back pressure and you can't lose too much by doing it. If you don't like it, go ahead to plan b

 

I have an evo, so my observations may not apply to TC's. I purchased my bike with the baffles completely removed from the stock exhaust. It was too loud for my taste, but ran okay. I installed some SE slip ons and found that my MPG improved by 10 percent. It sounds much better too.

 

Well today I drilled six 1/2 inch holes in each pipe. It is about half way to what I would like. Would love this sound on my 2012 ultra classic. My pipes are to loud on it on to quiet on my my breakout. I listened to Vance and Hines big radius at dealer today. Seemed to loud but bike was indoors. Love the look but 1700 installed with heavy breather and screaming eagle computer mod set up.

 

Loosen the clamp, 2 bolts and drill 3 rivets and the baffle slides right out. If your going to leave the cat alone just punch a hole in the center plug on the baffle. You can probably do it while on the bike. I saw where some folks use a long nail. Just another option, sounds ok but agreed, I would think a good set of slip ons may sound (tuned)better, but if your going that direction anyway what do you have to loose. You may be surprised. I was.

 

Here's an inexpensive option that will give a little volume and some more torque.

 

Haven't heard any muffs that's been drilled out of several YRs..

last one's I heard that was drilled out on a touring bike, sounded like a Old Volkswagen Farting going down the road..




.

 

I drilled out stock pipes with six 1/2 inch holes rans out but still not much louder. I but on my Rush slip ons tonight sounds good and looks good.

 

Try American custom exhaust. They are a site sponsor here. They did mine and my brothers stock pipes. Good folks and a great solution. Check their web site.

 

I drilled my Nightster baffles and it sounded eh.. not great but wasn't too bad. So when I traded it in for the Breakout I knew I was going to get a 2-1 exhaust, just waiting on some cash. Well I got impatient and went ahead and removed the baffles and removed the cats and drilled the center. Sounds like crap and performs even worse. I should have gone with my gut and just left the damn things alone and been more patient. Now I have to roll with these performance suckers till I can scrape the cash for my big radius I want. Lesson learned!