Mufflers with Cats removed

[jodog]

I have been gifted a set of 2007 mufflers which were cut open, the converter material removed, and then rewelded (very nicely). Has anyone here run such a set of mufflers? I would anticipate less heat at the muffler and a somewhat different exhaust note. I am wondering about the impact on fuel mileage.

Also, I have heard that 08 and later bikes might be impacted differently that 07 and earlier.

Does anyone have any first hand experience with cat-less muffling?

 

[mello dude]

There's a joke in there someplace...

 

[jonjonboo]

I have the older Staintunes that come without “cats”. I installed them with a highflow air filter and enhanced my performance and mpg.

 

[jodog]

I have the older Staintunes that come without “cats”. I installed them with a highflow air filter and enhanced my performance and mpg.

The staintunes also have a different configuration in the part beyond the cats, so we're comparing apple cats and orange cats (to create a bad metaphor). Any data points on stock mufflers sans cats re" mpg?

 

[SMSW]

Does anyone have any first hand experience with cat-less muffling?

Talk to @Shawn K.

 

[drrod]

Any data points on stock mufflers sans cats re" mpg?

Just a swag, but I am thinking that the number of people who cut open their stock pipes, removed the cats, and welded them back together is pretty small. Most people just replaced the units with aftermarket.

 

[Jjonahjamison]

I had a Kawasaki Vulcan Drifter that I had the cat removed from the muffler. There was a kind of cat box that both exhausts fed into, and the removal involved cutting out that box.

After it was done I had much more backfiring on deceleration, at night people behind me could see flames coming out of the pipes when it backfired. But I never noticed any real performance difference, other than the perceived performance of loudness.

 

[Catmandu2]

Does anyone have any first hand experience with cat-less muffling?

Everyone with slip-ons has first hand experience with cat-less muffling. But I know what you mean.

There have been several articles where owners have cut out the cat-plates. I don't recall hearing of any performance increases,, or fuel mileage improvements. There was a reduction in radiant heat down in the cat-zone,, and an increase in tendancy to re-burn. I don't think tone was affected much,, except for the re-burn. And of course,, the catalytic conversion was nullified. That is true of my slip-on's as well. However, tone and performance are improved,, due to reduced back pressure. And there is a deeper sound due to the baffled glass packs. Note,,, that the baffles on the Del's are not really baffles,,, they are closed deflectors that force the exhaust pulse outwards from the center flow, towards the glass pack chambers. I have tried my Del's with the so called baffles out,, but it is just a bit too obnoxious for my tastes.

Unless you are having issues with high heat off your pipes,,, or just like the sound of re-burn,,, I would recommend you just stay with your oem pipes. Having said that,, it only take 20 minutes to change them,,, you can't do any harm,, and you can always change them back if you want. It would be interesting to hear what you experience. Cheers,, CAt'

 

[bdalameda]

Here's a cat with a muffler


So sorry - I took this as a challenge!!!

 

[TerryS]

Here's a cat with a muffler


So sorry - I took this as a challenge!!!

And here's a muffer with the cat removed:

 

[Igofar]

Removing the cats from the mufflers is a very common Harley Davidson thing on their newest models....
You can probably find your answers surfing some of the Harley forums.
From what I've read, everyone who's done this, has had FI mapping issues and had to re-map their power commanders and race tuners.
Backfiring, flame, heat, mufflers burnt through the chrome etc.
Since you have no way to program the FI system in your ST I would probably suggest against going that route.
Ever wonder why it was altered, and then not used?

 

[jodog]

Removing the cats from the mufflers is a very common Harley Davidson thing on their newest models....
You can probably find your answers surfing some of the Harley forums.
From what I've read, everyone who's done this, has had FI mapping issues and had to re-map their power commanders and race tuners.
Backfiring, flame, heat, mufflers burnt through the chrome etc.
Since you have no way to program the FI system in your ST I would probably suggest against going that route.
Ever wonder why it was altered, and then not used?

Well, like many people on this list, when I'm told that there is likely impending doom if I pursue a particular path I am absolutely compelled to pursue it
I'll give a detailed update after the grand experiment. Generally I am not a fan of backfiring and flames, but it would help with that whole visibility from the rear issue.

 

[Shawn K]

Well, like many people on this list, when I'm told that there is likely impending doom if I pursue a particular path I am absolutely compelled to pursue it

Atta boy!

 

[rwthomas1]

Well, like many people on this list, when I'm told that there is likely impending doom if I pursue a particular path I am absolutely compelled to pursue it
I'll give a detailed update after the grand experiment. Generally I am not a fan of backfiring and flames, but it would help with that whole visibility from the rear issue.

Hmm, are you interested in a car tire I have for sale???

No, no, don't get up, I'll see myself out....

RT

 

[ST Gui]

and a somewhat different exhaust note.

A video or sound bite of the new exhaust note would be appreciated. Someone posted a cutaway pic or diagram IDRW of the 1300's muffler quite awhile ago. The baffling looked like it would keep any flaming to a minimum except what you might get here.

I might like a beefier note but not enough to gut the stock system (doing a nice job is beyond my skill set and wallet capacity) and I don't care for the looks of the various aftermarket systems.

Now if I could get mufflers something very much like

even

I'd try them in a heartbeat.

 

[Obo]

If you want more grumble you could try this at your own risk.... otherwise buy a pre-manufactured aftermarket set.
I'm assuming the the cats are still intact as I think they are at the front of the muffler and this mod only changes the flow path thought the packing that attunes the sound.

"Re: STock Exhaust Modifications.
Well this is now the third bike I've done this to with the same tools and I LIKE the outcome. (XX
and KLX are the others) Seems all mufflers have the same internal construction.
First off on the ST1300 the "Sewing machine" sound is the gear primary drive and the
counter balancers; THAT noise will always be there.
If you decide to do this first take some time to listen to your stock pipes. Remove the bags (they
quiet the results) and stand at the side and rev up and down with the engine fully warm. Also
stand at the rear and listen.
I found that from the side, the engine noise was louder than the exhaust sound. Just like my XX
was.
Since the ST has 2 outlets per muffler you can start slow and work your way up. Punch 1 small
hole in each muffler for instance and listen.
Do this with the pipes fully warm, you will punch through like butter.
I start with a rod of all thread 3/16'' thick and 20'' long with a nice sharp point on it.
Using a flashlight run it in one of the exit holes till you hit the baffle plate. It's deep. Now center
it in the hole precisely and hit it with a hammer. keep hitting the same spot till you punch
through.
Now all you do is move up in diameter, I have 3 rods total, final one is just smaller than the exit
hole.
Didn't take me long, pounding and listening till I had all 4 with a same diameter hole through.
Anyone who has/had a V65 Sabre (stock pipes) will love the sound! Noise regs were much less
in the 80's. Also much like a VFR.
It's not loud, it's not obnoxious, it's nice.
Now standing at the side, the engine and the exhaust are about the same volume.
Putting the bags back on quiets it even more.
What you are doing is allowing some exhaust gasses a straight shot through the muffler instead
of taking a back and forth route to the exit.
Engine seems to rev much quicker, seems much less choked off than before.
Doing this to my XX along with an ignition advancer, and some jetting got me from 135 hp on
the dyno to 147 hp."

 

[Uncle Phil]

Now if I could get mufflers something very much like

even

I'd try them in a heartbeat.

Those are sort of similar to the ones on a ST1100....

 

[ST Gui]

Regarding what Obo quoted above:

"Anyone who has/had a V65 Sabre (stock pipes) will love the sound!...
It's not loud, it's not obnoxious, it's nice."

And that's exactly how I felt about the OEM exhaust on my V65.

I also punched the holes. It sounds just a bit better, but the sewing machine sound is still pronounced... Maybe some more expensive aftermarket cans reducing/overlaying that whistling sound... Duno

Changing the tone of the exhaust won't help. As per the bit Obo quoted above:

"First off on the ST1300 the "Sewing machine" sound is the gear primary drive and the
counter balancers; THAT noise will always be there."

So volume or VOLUME is the only thing that will work – as far as exhaust goes. That's not a rode I would want to ride down.

This reminds me of the Itchy Boots Behind the Scenes video where Noraly mentions she added new mufflers to Ronin because it sounded like a Hoover!

Those are sort of similar to the ones on a ST1100....

And look almost exactly like the ones on my V65

 

[Igofar]

Regarding what Obo quoted above:

And that's exactly how I felt about the OEM exhaust on my V65.


Changing the tone of the exhaust won't help. As per the bit Obo quoted above:

So volume or VOLUME is the only thing that will work – as far as exhaust goes. That's not a rode I would want to ride down.

This reminds me of the Itchy Boots Behind the Scenes video where Noraly mentions she added new mufflers to Ronin because it sounded like a Hoover!


And look almost exactly like the ones on my V65

That's not a RODE you'd want to Ride down?

 

[beemerphile]

Cat delete...