SuzukiSavage.com - Drill out catalytic in Dyna muffler

stewmills

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Drill out catalytic in Dyna muffler
08/08/16 at 07:19:07

Ok...I have known this since I installed it but it was what I could find local at the time, and for $20 I wasn't complaining.

My Dyna is a CAT version. I have no rough running issues and no bluing around the muffler after 1.5 years. However, for anyone that has been able to compare, is it worth my time and better performance to try and find a non CAT version or is it trivial since I am not racing this thing...

Or, is it viable to get something like a hole saw and take a 1.5" or so plug out of the CAT (that I think I can see down in there...that waffle-honeycomb looking thingy).

I appreciate any insight. Bike runs great, just don't want to be skimping on a little power boost if a non-CAT or drilled out CAT would offer something worth the trouble?

Thanks!

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Dave

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Re: Drill out catalytic in Dyna muffler
Reply #1 - 08/08/16 at 07:34:47

I removed a catalyst from one muffler.....it is a pain in the tuchus. The stuff is really tough. I used a hole saw first, and then a smaller drill to make holes in the parts the hole saw didn't remove, and finally a chisel to remove the pieces.....I think it took a couple of hours to get it all out. (The catalyst is a larger diameter than the 1-3/4" ID of the inlet....so some of it cannot be removed with the holesaw that can do down the inlet).

Did it make and difference....not sure as my neighbor installed it on is 800 Volusia!

Might be fun to have some energetic member do a before/after comparison! Wink

Dave

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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28668 Tucson Az Gender:	Re: Drill out catalytic in Dyna muffler Reply #2 - 08/08/16 at 07:53:32 I don't think it restricts much at all....it's just a heat coil. It might even smooth exhaust pulses making flow better... Who knows?... wouldn't worry about it...
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stewmills

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Re: Drill out catalytic in Dyna muffler
Reply #3 - 08/08/16 at 07:57:25

Ok then...It sounds like we need a guinea pig to test this?

I'm not in a big hurry so long as riding weather is good here, but maybe when I have some spare time (and we have lots of rain) in the next week or so I will see about commencing with this experiment for the Savage's sake.

Dave, I presume that the honeycomb looking stuff I see there in the "header" end of the muffler is the CAT? How thick/deep is it, and is there a risk of drilling too deep and hitting a baffle or such behind the CAT that I don't want to mess up? I do have a garbage DYNA that I will test the drilling on first, but the more I know ahead of time the better prepared I will be.

Thanks!

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Dave

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Re: Drill out catalytic in Dyna muffler
Reply #4 - 08/08/16 at 08:01:02

No problem drilling too deep.....the end of the catalyst stops well short of the baffle. The cataylist is about 1.5 - 2" deep from what I remember...and there is about 2 inches behind it before the muffler necks down to the baffle. The darn stuff just doesn't cut, drill or chisel easily....it deforms and just wiggles of the way of the drill and chisel....and the hole saw is the best bet.

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justin_o_guy2

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Re: Drill out catalytic in Dyna muffler
Reply #5 - 08/08/16 at 08:20:15

I'd first look at the thickness of the honeycomb walls. Just how much is it actually blocking flow? And, as Bot points out, maybe it's doing some good?
All that said, usually when I tackle something, it's to solve a problem. You don't Have a problem, but, you might if you go messing.
If you want to explore it, I'd recommend buying a non catalytic muffler. The labor to get it out, by Daves description, is more hassle than I'd jump on for a twenty buck reward. I'm not comfortable with doing a mod that can't be undone and there's no precedent, especially when it is to accomplish nothing more than
Let's see what happens..
You can protect yourself from disappointment and Not have to do that work, just by buying a muffler.
And, you'll have a spare.

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stewmills

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Re: Drill out catalytic in Dyna muffler
Reply #6 - 08/08/16 at 08:41:20

Yeah, it's all hard to decide. I too wonder if the additional back pressure may be helping a little? Heck, since I have the spare muffler maybe I will try the drilling out procedure on the spare (it's all scratched and dinged up, but from the pair). If it works, I can mount it and see what the difference is, if anything?

Like you said, JOG, nothing is broken so I don't want to waste too much time creating a problem...but I am curious Wink

JOG, here's your new coffee mug;

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Drill out catalytic in Dyna muffler Reply #7 - 08/08/16 at 09:11:18 Maybe a fat drill bit rammed through in a few places would be easier than trying for a complete removal and would be enough to show you if it's heading in the right direction and would you be ahead to get a new Dyna..
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Dave

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Re: Drill out catalytic in Dyna muffler
Reply #8 - 08/08/16 at 09:17:25

justin_o_guy2 wrote on 08/08/16 at 09:11:18:

Maybe a fat drill bit rammed through in a few places would be easier than trying for a complete removal and would be enough to show you if it's heading in the right direction and would you be ahead to get a new Dyna..

Until you try working this honeycomb stuff....you really can't appreciate how stubborn the catalyst can be. When you run a drill through it.....chips don't come out of the hole....and the hole closes back up when you pull the drill bit out (And you have screwed up the honeycomb around the drill hole so that won't flow anymore). I don't know if anything in it was harmful - so I wore a respirator while working on it. I thought about using a cutting torch - but I didn't know if anything deadly would be created in the smoke!

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Drill out catalytic in Dyna muffler Reply #9 - 08/08/16 at 09:22:40 Well, Dangitt Dave, that sounds like a real fun project.. Stew, the dude has spoken. Ignore my idea.
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Dave YaBB Moderator ModSquad Offline SuzukiSavage.com Rocks! Posts: 18101 Camp Springs, Kentucky Gender:	Re: Drill out catalytic in Dyna muffler Reply #10 - 08/08/16 at 09:49:42 I found my old thread on this subject....... http://suzukisavage.com/cgi-bin/YaBB.pl?num=1412879119/0#3
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12Bravo Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 628 Mid-Missouri Gender:	Re: Drill out catalytic in Dyna muffler Reply #11 - 08/08/16 at 14:10:34 Most of the Harley guys just cut the side of the muffler out in order to remove the cat then re weld the muffler back. I haven't removed the cat from my Ultra Limited and don't plan on it either.
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