1190 standard Exhaust, Baffles removed, Pics & Vid

So instead of forking out $900 for a wings shorty, or $1500 for the Akra, I decided to gut my standard muffler first to see how it sounded, I figured if I didn't like it I would just buy the wings anyway. By the way, I love the look of the wings shorty.

I have pics of the whole process but I didn't bring them to work with me so I will update the post tomorrow with pictures, for now just watch the video to hear the end result.

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I'll post another video next weekend from off the bike so you hear what it sounds like as a spectator.

This is not an easy task, in short, you have to cut either end of the standard muffler casing, then we used a press to extract the centre section from the outer casing, than used a length of 2 1/4'' perforated pipe as my new centre section, repacked with muffler packing like a motocross muffler, than weld back together. Also added new piece of stainless 2 1/4 '' pipe as the new tip to protruded through the end cap.

I wouldn't bother this diy unless you or someone that's willing to help you is competent with an angle grinder, a die grinder, a press & a tig welder.

I couldn't be happier with how it sounds, its actually not as loud as I was expecting, it has a really nice V-Twin note on idle and on cruise but when you load it up or give it a quick rev it has that (ducati 1098 with exhaust system) sound...really tuff but can also be subtle when you're done clowning around.

I'm happy to fill in the finer details for anyone interested in doing this themselves.

I just want more riding vids

I just picked up a cheap second hand standard can and will look to mod it over the next couple of weeks. What I'm thinking is having a rotating tube or flap arrangement that can be moved using an external rod. Basically to swap between standard strangle and what you've done.

how is the fuelling ?

Dremeled off the end cap end and extracted the pipe as per IJETs 3rd picture.

Following the zorst from the engine there are 3 chambers in the can.

- First the gas flows through a pipe (that passes through the first chamber) that dumps it into the center chamber.
- Then the gas makes its way from the middle chamber through the centre hole and the two little holes in a plate and dumps into the 3rd chamber. See IJETs 2nd pic which is taken from the rear of the can.
- From the 3rd chamber it flows back through a pipe to the first chamber. This pipe is the bottom "hole" in the plate in the 2nd pic.
- I've not opened the front of the can to see what happens in the first chamber, but from there it flows straight out the pipe IJET shows in pics 3 and 4.

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So basically the flow goes, inlet flange, pipe to 2nd chamber, holes in plate to 3rd chamber, pipe back to first chamber, pipe to outlet.

I'm having a close look at one option to have a rotating or sliding concentric pipe sleeve valve on the outlet pipe, in the the middle chamber.

Rotating has advantages in control of the size of the transfer hole, and sliding is probably easier to control.

I will consdier this over the weekend.

Had a good look and a rotating sleeve is too hard, but a sliding one looks practical. All I need is some 41mm id pipe and some 5 mm rod. The plan is to make the sleve with the rod already welded to it. Drill a hole in the plate between the 2nd and 3rd chambers and also through the end cap.

The pipe from the intake is large enough to slide the sleeve from that end through and into place.

Now to work out how to actuate it remotely.

So dremelled off the end a few weeks ago and the end plate slides out with a pipe.





The pipe od is just over 42 mm and I found some pipe of the right id off one of the spawn's dead peddlies.





I cleaned up the inside of the pipe and it slides easily with enough clearance over the pipe.



The plan is to cut part of the pipe and sleeve so that it can operate in the centre chamber which you can see in the following photo.

Basically the normal flow is from the bottom in this picture. It dumps into the center chamber and flows through the centre hole and the two smaller holes in the plate to the rear chamber. Then reverses direction and flows back thorough the pipe (right hand in following pic) to the first chamber. From there it reverses direction again and flows back through the pipe that slides through the two holes you can see on the left.



I need to get the measurements right and then drill a couple of holes in the plate and end plate to weld a rod to it so that I can slide the sleeve over the hole to either cover it up totally for standard zorst, or a large gap. I have no idea what it will sound like and still haven't worked out how to adjust the slide. I'm trying to work out how to adjust the slide when riding. Something like a peddly gear controller is looking the go, but how to organise a simple and reliable mechanism at the end of the zorst is still eluding me.

Did some more experimenting this afternoon.

Took some measurements and worked out that a slide of about 80mm would be about right.



Then looking at the slide I played with a couple of different shapes. A round profile went from nothing to a lot in a short distance then slowed down as it was opened further. A wedge shape would continue to increase the size as the slide was moved. Wedge it is.



Then cut the hole and welded a rod onto it.



Sliding the thingie then opens the transfer hole.




Found some 6mm rod and the best place to drill through the end plate as follows





I got a little carried away with the next steps and didn't bother to take any pics. The next pic is the thing all assembled and with the rod in this position the transfer is fully open.



I put it on the bike. I couldn't resist starting it with no can at all. It sure has some character with a straight open pipe!

The sound fully open wasn't overly loud. I will pull it apart and change the hole to make it bigger.

I only put a couple of tack welds to hold the end plate on, you can see one at the bottom so it will be easy to get off again.

Why not connect the inlet direct to the outlet with a length of perforated stainless tube, wrapped in stainless wire wool then silencer packing? Like an Akrapovic or other performance exhaust.

Yeah, I considerred that like the OPs posts above.

I'm trying to organise it so I can change it as I go. Like crawling home late at night, best not to wake up Mrs P!. Then with a twist or a lever pull make it sound like a real v-twin.

how much weight has been saved through your cut and gut?. It sure looks like that can is made of some sturdy stuff.
Its been a while since you all did these experiments. How did the reassembled pipe work for you ?

Can't quote any figures but trust me that center baffle section I removed weighed a shit load. But also keep in mind the outer casing is still stainless steel and quite a large size so compared to a titanium or carbon muffler it's still heavy, probably half if not more as lite as stock though.

After about 25,000 kms it started to get a bit louder as the muffler packing burnt off. The bike is gone now but it was probably due for a re pack. Also if I did it again I would have used a few layers of stainless steel wool first before the packing so it lasts a bit longer.

Whach these two vids. The first one was at about 20,000kms and the second one was taken when the bike had about 26,000 kms. You can here it sounds a little raspy and needs a re pack in the second vid. Both vids filmed with the same smart phone.

http://vimeo.com/85596026

http://vimeo.com/93057621

thanks...Ya you wonder why they built the can so heavy. You'd think much lighter components could have been used.
What bike you riding now ??

1290 SD

I've reserected this thread from the dead...

I just couldn't justify spending $1000 for one of the more popular aftermarket cans so I bought a previously enjoyed OEM muffler for $100 on fleabay. I plan on doing the mod ... I'll try and remember to take some picutres along the way.

I'll post my experiences with the modifications and offer my impression of the new exhaust sound with the OEM look.

Not a fan of the Super Duke muffler swap? I'd recommend doing that before gutting the stocker.

Can u get em for $100

Paid $75 for mine, shipped, on Ebay. It mounts to the stock header no problem, you just have to make a mount for it.

I paid $170 shipped for mine, it looked almost new. There's one for $190 shipped right now.

It's quite a bit lighter too, 6.3 lbs vs almost 14 on the stock.
here's a thread about it.
http://advrider.com/index.php?threads/super-duke-muffler-install.1201216/