Ducati Monster Forum

I have a 620 and I am thinking about coring the exhaust. My mechanic said the bike will loose a little mid-range power and he did a before and after dyno test with another monster. Anyone have any experience with it? Would you recommend doing it?

Do it you will be fine.  Coring only allows for more airflow out but since you are not allowing more fuel/air in the only thing it really affects is back-pressure and 4 stroke engines are not affected too much by that.

not if he sets the fuel trim correctly.  I had it done, for about 85 bucks after I put my cored cans on. Didn't notice any difference negative or positive


Just loud as hell  [evil]

I had a half core done on my 696 exhaust, it sounds great and there was no negative change. I tried the full core first and they were crazy loud, so I switched for a set of half core and they were just right. Deep, loud and great sounding.

You can half core the exhaust?

Yea, the guy who did mine just took out one baffle instead of all of them. He can tell you more about it, he is on the forums here, screen name ryanracer. He did a great job for me, so you might want to give him a shout.

There are three chambers in the typical Ducati exhaust (before the under-tail ones appeared, and the S*R pipes).  The exhaust comes into chamber 1, goes through some tubes to chamber 3, goes through some more tubes to chamber 2 in the middle, then out a single tube passing through chamber 3 and out the back.  You can cut the tubes in either chamber 2 or 3 to get an improved sound, but not affect back pressure or tuning much.  It sounds good, but won't make people deaf.  I don't like the fully cored exhaust pipes, personally.

I've cored pipes both ways.  On a Monster, it's easier to do chamber 3, because it's hard to get to chamber 2.  On most other Ducati exhausts, like the ST2, SS, 851/888, and so forth, it's easier to do chamber 2.  Either way will make the bike sound like a proper Ducati.

Would you recommend doing it?

Absolutly!  Core those cans young man. [thumbsup]

And no half way measures either.  Go big or stay at home. [clap]

LA

OK, so when I look into my cored 620 exhaust, I see three open tubes looking back at me.  Is that a "full cored exhaust"?  (I bought them off someone on TOB)

Either way, it's not that much louder than the stock, and my ass-dyno certainly didn't notice a change in power.

Mine are the same way, and I think they sound much louder than stock (but not nearly as loud as  no pipes at all).  I had db measurements for stock and cored that I had posted on TOB.  I think I still have the comparison charts at home.

I cut mine back so they are 11" long total length.  I popped the ring out as well. Ive heard that is what makes the biggest difference in sound is popping that ring out (well its not as easy as it sounds, you have to grind the welds off to be able to smack it out with a hammer) so half core is leaving that ring in full cored is taking that ring out.

Not quite.  Generally, "fully cored" means removing all of the internal chambers.  If you leave chambers 1 and 2 unmodified and just remove everything in chamber 3, the back chamber, including that ring, it would be consider "half cored".

hmm guess mine is half cored then. I think if i look in mine i see three chambers.....oh well its loud enough for me.

If you look into yours, you will see three tubes going into one chamber.  The chambers are separated by flat sheet metal.

Doh! thats what i meant to say three tubes. So past that flat sheet of metal there is two tubes you are saying, so at that point once you get it back to two tubes its a full core or do you need to cut the tubes back til you get to the next sheet?

I think ill stop showing the world how dumb i am now.

A full core removes both of the sheets as well as all of the tubes.  If they don't put anything back inside, it's awfully loud, and in my opinion, does not sound very good.  Some people prefer loud regardless of sound quality, but I'm not one of them.

dam at that point your pretty close to just having straight pipes.

Except that straight pipes sound better.  Seriously.

But those who do it seem to at least feel the need to look like they have mufflers on their bikes.

One could also fully core the cans and replace with straight perforated tubing fore to aft and pack with fiberglass. This is pretty much what Termis are. I have partially cored cans and they do sound quite good, and are loud but not obnoxious. Neighbor came running out of the house one morning to tell me how beautiful my bike sounded. How often does that happen.

I'm thinking of fully coring them out along these lines:   http://www.ducati-upnorth.com/tech/coringsr.php

I have the Termi kit with a midpipe yet I prefer the look of the stock mufflers. You could pick up another set of stock pipes pretty cheaply if you don't like what you've done.

For those that ride with cored pipes, did you need to do anything else to keep it running smooth? Re-mapping or anything?

Thanks

cant speak for anyone else, but i didnt have to do anything. Runs like it did when i had the Arrows on it.

Do you have a modded airbox and have you noticed any difference in fuel consumption?

No modded airbox.  No its the same as far as i can tell.