There have been a few threads on coring original exhaust but having just done it myself, I thought I would add to the collective knowledge.
I did it in two stages. The first was to open up the end of the original can. I then put them back on and rode around for about six months (boy was I tired). I then did the second stage which was to largely gut the cans and replace the internals with perforated tube and fibreglass packing. I took photos along the way so it helps to understand what’s happening.
Let’s start with the first stage. The first trick is getting the end cap off. It is held in place by two tabs. The only real way to get to them is to cut the inside the exhaust outlet. This is where a dremel comes in handy. Because the dremel is in the way you can’t see what you are doing. It’s a matter of making numerous small cuts and trying to join them up until you have cut right around the inside of the exhaust outlet. Once you do this you can then pull the end piece out. It might take a bit of effort but be persistent. Mine got a bit deformed getting them out but I was only going to toss them anyway so it didn’t matter. Repeat for the other exhaust.
This photo shows the bottom one removed.
This is the bit I cut out.
Once the ends are out you can look inside the exhaust to see the two tabs that hold the end cap on. There is one on each side. Use the dremel again to cut through these. The end cap should then come off.
Once the end cap is off and the mounting bolts removed the aluminium sleeve should slide off. Again it might take a bit of gentle persuasion. Try not to damage it as this is one part you will re-use.
The S2R exhausts have three chambers. Exhaust gases go into the chamber at the rear of the bike first, back through the middle chamber to the front chamber and then out the end pipe. Cutting off the back end of the can allows the gases to go straight through and out the end. There is a photo further below of the internals. I cut the end off with an angle grinder. I then put the end caps back on and secured them with rivets.
This is pretty much the first stage. It gives you a straight through exhaust but has no packing and still has almost all the original weight. It improves the sound but I found it a metallic sound and not very refined. It’s difficult to describe but its way better than the original exhaust sound that strangled the distinctive Ducati sound. I didn’t notice any performance difference with this mod, better or worse.
I did the second stage about six months later. For this you will need to buy some things. I bought some perforated tube which is made from steel. I also bought a bag of fibreglass exhaust packing. I found both at a local exhaust shop.
The idea here is to lose as much weight as possible and allow better breathing due to a bigger outlet the whole length of the exhaust can. The packing will also improve the quality of the exhaust note.
I started by drilling out the rivets and taking off the end caps. I then cut down the exhaust with an angle grinder. I left the section where the mounting bolts are so that the cans could be remounted with the original bolts. This takes a bit of effort and I actually cut it in two parts. It could probably be done in one but you just need to keep looking to see where it’s attached. If the parts you want to remove won’t come off easily, have a good look to find where it might still be attached. Once you take off the outer shell you can finally see the internal system of chambers and pipes.
Cut these pipes off as low as you can. The exhaust pipe enters the cans at an angle and you want the perforated tube to be straight so the lower you can cut the original pipe the better. Once I cut off the pipe I put some slits in the remaining pipe so I could bend it a bit to get it straight. It’s not pretty but it’s all going to be inside so you won’t see it.
Here are the ingredients for the final can.
Slip the perforated tube over it to see how it’s going to sit within the aluminium sleeve. Once you’re happy it’s going to be straight, measure the perforated tube for length and cut it accordingly.
I then stuffed the exhaust packing down around the outside of the perforated tube until the whole exhaust was packed. I made sure I packed them so that the tube lined up with the holes in the end caps.
I then refitted the end caps and riveted them into place.
I thought that this was the end of the process but I discovered I had a bit more work to do yet. I started the bike and everything was fine but when I revved it, some of the fibreglass packing blew past the tube and out the end. I imagined myself riding down the road with a trailing cloud of fibreglass. No, that won’t do.
Back off with the end caps. Luckily my brother in law has a sheet metal business so I had him knock up some aluminium plates the same size as the inside of the exhaust cans with a hole the same size as the perforated tube. A bit of minor adjustment to the shape with a file and they were a flush fit. I then fitted them just inside where the end caps fit on so they would hold the packing in place.
Just to make sure they sealed I put some exhaust sealant around the gaps. Again, it looks ugly but will be covered by the end caps. The plates also hold the perforated tube in the right place so they line up with the holes in the end caps, more or less.
A quick test ride revealed more bass in the sound and a less metallic sound. It also revealed a significant improvement in tractability at low revs. The bike used to chug a bit below 4000rpm but now it just pulls smoothly from as low as 2500. I kept riding around seeing how low I could have the revs and still pull away cleanly.
Looking down the end of the exhaust you can really see the difference.
Before:
After:
All up, this mod cost me less than $100 and a few hours work and was well worth the effort. I hope I have inspired others to get in and have a go. Remember, if you stuff it up, buy another set from the for sale section, hide the stuffed ones in the garage and deny it ever happened.
