After Chopping and Coring

[WetDuc]

What, if any, adjustments need to be made to a monster after chopping and coring the cans?  I have seen some guys on this forum noting engine issues after the mod, and some adjustments were recommended.  I'm getting ready to do mine and would really appreciate knowing what I should do after the mod.  I have a '08 M695 all stock engine and electronics.

[booger]

If you only core the cans a fueling adjustment is generally not required. If you chop or otherwise mod the airbox to flow more air you will require a fueling adjustment.

[yotogi]

If you only core the cans a fueling adjustment is generally not required. If you chop or otherwise mod the airbox to flow more air you will require a fueling adjustment.

+1, if your bike is running fine, you are luckier than some and should celebrate by riding the hell out of it!

[WetDuc]

Let me clarify.  I have not chopped or cored the cans yet.  I am about to.  I checked the how-to on this forum and it seems that the only thing the tutorial instructs to do is take off the cap and cut the innards out about 3" back.  I took my cans off today and started her up and nearly orgasmed.  I have the cans in the house and I'm getting ready to do this.  I thought there would be some kind of sound baffle to take out.  Am I wrong?  If there is a how-to thread I missed, some direction to a better thread would be great.  I am looking at the how-to thread created by caffeinejunkee.

[WetDuc]

How the flip do I get the flippin sleeve off?!

[booger]

Let me clarify.  I have not chopped or cored the cans yet.  I am about to.  I checked the how-to on this forum and it seems that the only thing the tutorial instructs to do is take off the cap and cut the innards out about 3" back.  I took my cans off today and started her up and nearly orgasmed.  I have the cans in the house and I'm getting ready to do this.  I thought there would be some kind of sound baffle to take out.  Am I wrong?  If there is a how-to thread I missed, some direction to a better thread would be great.  I am looking at the how-to thread created by caffeinejunkee.

my bad I thought you wanted to know if there were any adjustments to be made to the bike after the coring was done

[WetDuc]

Got the sleeve, done for tonight.  Should finish up tomorrow. 

[yotogi]

Sorry I missed your questions about getting the sleeve off. Total pain in the ass to properly core cans, eh? I did mine on the S2R1K and unfortunately am not able to run them because it leans my current build out too much.

As long as all you are doing is coring out the cans, you probably will not need anything else done to the bike. If you start messing with other parts of the system (most notably modifying your airbox) you will probably run into the lean condition. Good luck and keep us posted.

[WetDuc]

Got everything done this morning.  I have a few small position adjustments to make to the cans after work today, but those are minor and should go quickly.  The bike sounds AMAZING.  It seems to be running normally, and I've only had it for about 6 months, so any small drop in power would be really hard for me to notice.  All feels well.  If it is running too lean, what should I look for as symptoms?
I'll take some pics after work, too.
Chopping and coring is harder than it may seem.  Those cans are built so that they are not meant to be opened, but brute force fixed that for me.
I'm curious as to the three pipes I see inside the can.  When I had the cap off, I looked into the can and saw the main pipe that used to run out the cap, and two other shorter pipes off to the sides of the main pipe.  When I put the cap back on, it dawned on me that with the stock setup, those pipes used to be in an enclosed space, and now they open up to the exhaust outlet.  Is that what was bottling up the sound?  Just curious, so far so good.

[yotogi]

Chopping and coring is harder than it may seem.  Those cans are built so that they are not meant to be opened, but brute force fixed that for me.
I'm curious as to the three pipes I see inside the can.  When I had the cap off, I looked into the can and saw the main pipe that used to run out the cap, and two other shorter pipes off to the sides of the main pipe.  When I put the cap back on, it dawned on me that with the stock setup, those pipes used to be in an enclosed space, and now they open up to the exhaust outlet.  Is that what was bottling up the sound?  Just curious, so far so good.

The air would enter the can, travel the the back, bounce off a plate, travel back to the front, bounce off another plate and the go all the way to the back to exit. It certainly did a good job bottling up the sound as well as corking the crap out of the motor.

Keep an eye on your plugs if you are concerned that you are running too lean. Short of actually putting it on a tester to check your exhaust that is the best way I know of. Anyone else have any advice?

[WetDuc]

I got a tip that I could use high temp silicone sealant at the joint of the can to the collector to avoid any leaks.  Has anyone tried this? 

[stopintime]

Even if only by a little, coring will lean out the fueling won't it?

Considering these bikes are so lean from the factory that they can get blue header pipes, melting head paint and white plugs I think having the fueling adjusted is a good idea - cored or not. An hours work or so at the shop?

[ducpainter]

Even if only by a little, coring will lean out the fueling won't it?

Considering these bikes are so lean from the factory that they can get blue header pipes, melting head paint and white plugs I think having the fueling adjusted is a good idea - cored or not. An hours work or so at the shop?

Theoretically coring should not change the mixture.

[brimo]

Just coring the cans "should" be okay, however if you also cut the airbox (which of course you must do if you want the authentic Ducati sound" then you may need to think about a remapped chip or PCIII or similar.

[ScottRNelson]

When I used to have the M900 Monster, I tried all combinations of stock airbox, open airbox with jetting changes, stock pipes, cored pipes, and straight through slipons.  I couldn't tell any difference in performance due to pipe changes alone, except at high rpms when close to redline.  If the bike seems to run fine, don't worry about it.

As for the tubes in the stock pipe, there are three chambers in there.  The exhaust comes from the engine into chamber 1, goes through a tube from 1 to 3 (ST2 mufflers use multiple tubes), goes back through another tube from 3 to 2 (ST2 has more, again), then out a single tube in the middle from 2, through 3 and to the outside.

The result is that it goes into chamber 1, through tubes to chamber 3, through more tubes to chamber 2, than through a tube out the back.

If you cut out the middle tube on a Monster muffler, the result is that you go from 1 to 3, then out.  On my ST2 mufflers I cut all of the tubes out of the middle instead, so that one goes from 1 to 2, then out the center tube.  It still looks stock to anyone who examines it (and doesn't take the sleeve off).

Either modification doesn't lighten the muffler much, but lets a much better sound out without being overly loud.  I like the way Ducatis sound with lightly modified mufflers.

As for using silicone sealant, I've had good results using Permatex® High-Temp Red RTV Silicone Gasket on mine.  Without it, you'll get some exhaust blow-by around the edges which makes the pipes always look dirty.  Use some on any rivets or screws that you use to put it all back together as well.