Coring an Ducati monster S2R exhaust

Coring an S*R exhaust

I did this because I really liked the shape of the original exhausts and none of the aftermarket ones look as good in my opinion.
Its also turned out to be much cheaper,though obviously more work than a commercially available set of cans.If you fancy a go then I recommend getting a spare set like I did,that way if you mess up you can hide the lot and swear blind you meant to do that in the first place.
S2R and S4R cans are identical and interchangable.

Hope its of use to anyone who fancies doing the same.
The tools I used werent particularly special but the first thing you'll need is a dremel style mini drill possibly with a flexible extension,with a small enough cutting wheel to fit into the exhaust outlet,as this is the only way into the cans.I used a hacksaw to cut through the internals,I've since bought a cheap angle grinder/cutter and wished I'd bought it sooner as the metal is quite hard.

This is the first steps in getting access to a set of S*R exhaust cans
If you look inside the exhaust exit you'll be able to see a weld,I cut just inside this.

I spent a while trying to make sure the cut was all the way through with the cutter disc breaking regularly.Your almost working by feel as you cant see into the pipe while your cutting,I ended up making duplicate cuts because of this.

A bit of brute force was needed here,I realised I had actually cut through the steel and it only needed persuading to get it out,if you insert a bar or old screwdriver into the cut and lever it around,the cap will move.Just 'walk' it out.

You can see the stump I removed and into the body of the can,you can just about see the bracket securing the end cap to the internals.
Thats the bit I found hard to visualise from the outside.

Slightly clearer here

After the brackets are cut (and I nearly put the cutting wheel through the whole end cap..whoops!)
Note the dust underneath,there was a lot of this and I should have worn a dustmask
the end easily pulls off

A whack with a rubber mallet while holding the sleeve loosened things up a bit

Actually this took me by surprise,the sleeve is only cosmetic!!

I had to stop at this stage because I couldnt find any goggles and the sparks from the cutter were flying every where.When I restarted( a month later) I tried to drill out the end tube first,more to find out what was there than any great plan.You can see the result further down,not worth the effort,just cut it!

The two cans differ slightly insofar as the top one has nuts to secure the external heatshield with bolts,I chose to keep these and ended up cutting away most of the metal around them leaving a strip of steel from the base with the bolt holes on it.This doesnt hold any weight and what I left was quite flimsy but was simply to keep the bolt holes in position when I replaced the alloy sleeve.
You could also just cut them away and attach the bolts directly to the sleeve,if you do this I'd also seal them with silicon sealant.

This is the top can.A straight cut through the top of the internal box will open it up,I did this with a hacksaw but have since bought a cheap angle grinder/cutter which would have been much easier and quicker

This is what you'll see,that bolt is for securing the heatshield

Note you can see all the way through now,this is what most of the US conversions are like,I on the other hand, had a different plan.

This is the remains of the bottom cans baffles,its whats inside each of the exhaust cans.I originally tried to drill onto the end of the can but gave up and cut it at the edge,you can still see the lip attached to the end of the internal pipe.

Heres the whole bottom can, this was the exploratory one for me,I dont recommend cutting it up like this as its more work than you need,but I wanted to know how the can was constructed and took it a little at a time.
Cut just above the support boltholes and you'll be left with the base section on the left here,thats all you need to do for the bottom can.

Heres a view down the stump of the lower can resting on its baffle,notice the two bolts protruding internally, thats what mounts it to the support and the frame....you'll want to keep those on both cans.You'll notice the internal pipe is not central,this became a problem when I tried to secure the new pipe and I ended up cutting this further down until the new one fitted almost centrally on both pipes

Just placed the endcaps back on the sleeves here, you can see the cut metal inside this would be hidden by soot if it was run like this but I thought it was messy looking and after trying it like this on the bike I found it was also a bit too loud for me too.This is what most US conversions are.

I've missed a bit out here,I forgot to photograph it, so have drawn a diagram of the whole thing.
I drilled four holes through the endcaps and alloy sleeves to take securing rivets,these were quite small and are only to secure the outlet cap from blowing off,alloy rivets are fine and it'll mean I can get them out easily for when I get round to colouring the sleeves black like I first intended.
Basically I then got two lengths of perforated tubing and cut them to length,I then cut a few slots into the ends of the tubings to enable me to bend it out slightly to nest over the endcaps inside edge.

I wrapped as much exhaust packing material around it as I could while allowing me to slip the sleeve back into place,I used the mounting bolts to hold it all in place while I positioned the endcaps.The outlet caps needed a firm push and some minor fiddling to ensure the perforated tubing nested correctly,once the first pop rivet was in it was a bit easier to do the rest.I also put a little sealant around the endcaps helps keep it from blowing.
A few pop rivets later and I mounted it all back onto the bike.


It now sound like a Ducati should,if this would be the only modification then you may get away with running it without any need to alter the fuelling etc., but I've also replaced the catylitic convertor AND put in an open airbox with a DP filter so mine need adjusted as it will run lean otherwise.

Here they are a few years later , with no problems, you can see straight through the top can here,also sitting beside it is a piece of the perforated tube used to rebuild the insides.