Making stock mufflers louder??

[1haugster1340]

I have the stock fishtail mufflers for my 1995 Heritage Softail and I would like to make them louder. I like the looks of the fishtail muffler and will use these until I find a used set of true duals. The outlet holes look rather small on these mufflers and I am wondering if it is worth the time to drill them out. Has anyone drilled out these mufflers and how good did they sound? What type of drill bit did you use? Thanks for the help.

[chipster]

While I realize that you've got an evo engine, go to the Twin Cam section andread the posts concerning stock exhaust. I think that you'll find it interesting. Unclepsycho has done some of what you're discussing!

Congrats on the new bike , by the way!

[rjrivero]

Can the tips be taken off? V-Rodders have been cutting the baffles out of their bikes for years. They call them "V-Mod's."

[unclepsycho]

Here's the link to one thread about modifying stock mufflers.

stock exhaust / perfomance

Frisco-rigid is another great source of info as well as Harleycruiser and others too.....

[frisco-rigid]

The Fish-tails I meddled with years ago ( don't recall what make) had a couple 1/4" x 20 screws holding on the """Fish-tails"""..
Once removed noise and perfomance increased..

I'm guessing yours do not have detachable ends..

Fish-tails have no flow efficiency,, they're just for looks I rekon,,, so if you don't cut em up you can sell em to a "Looks" dude & buy good slip-on's....
----I came to edit cuz I forgot to ask if your Fish-tails have the round exit with the cosmetic fin on top or do they actually have the old-style "verticle smile"..
The former are just regular, the latter are the ones with no flow..----

If you're like me however, you'll divide em before the night is over & start looking for possible perf mods..

You can always cut them precisely in half and weld in an assembly ring..
Then you can remove a wee bit, re-assemble,, do a Boxers or Briefs dyno run, then dis-assemble & add/remove & re-assemble at will..

When you say drill out the muffs, do you mean the baffles.?
If it's the "plug" type of baffle that looks like it goes straight thru you can either drill it small and then drill larger as you wish OR just totally Knock it out.. Sometimes drilling or knocking them out gets you a chirp/whistle that's kinda annoying.. I've knocked them out & gotten it and knocked them out and Not gotten it, just never know which you'll get..
When removing/gutting the insides you'll get better & better perf UNTIL you cross that line where it's nothing but noise & perf goes negative swiftly..

Have a ball

[1haugster1340]

Thanks for everybody's input. I think I am going to look for a set of Screaming Eagle bologna cut slip fits to put on the factory head pipes. I am need of the factory exhaust hangers for the bike. I got everything but the factory hangers for my exhaust system. If anyone has the mufflers or the hanger please send me a pm. Thanks for all the help.

[taccman]

Can someone advise, my sportster (model 2009) have a O2 senors. So modifying the exhaust affect the O2 sensor?

Or it does not matter at all?

Thanks in advance.

[frisco-rigid]

Hey Tac

The 02 sensor is the rat-fink of the closed-loop EFI..
Changes don't affect the 02 sensor, instead,, the 02 sensor affects and often nullifies whatever changes you make..

If you change exhaust and lean out a wee bit the 02 sensor will sense that and tell the computer which hopefully can adjust the A/F mix with-in a certain range..

I fought and experimented with my EFI car for years before I eventually gave up.. Re-programming/mapping is usually the only way to allow big changes..


Here's a link that will tell you alot..

Harley-Davidson Motorcycle Fuel Injection Explained

[unfknblvbl]

Originally Posted by taccman

Can someone advise, my sportster (model 2009) have a O2 senors. So modifying the exhaust affect the O2 sensor?

Or it does not matter at all?

Thanks in advance.

taccman- I'd reccomend taking this over to the sportster section. However, a buddy of mine I ride with has a 06 sportster and he punched his baffles out. As far as the O2 sensors are concerned, making a change that small I think would have no effect. I don't fully understand baffles, but I'm under the impression that their simply to reduce noise.

My buddies bike at idle is extremely quiet, but at WOT it comes alive and sounds like a Harley should.

[taccman]

oh.. thanks. btw is 06 sportster is a EFI model?