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Discussion Starter · #1 · (Edited)
After lots of reading up on the subject and getting not much more than a bunch of unanswered questions I decided to attempt it myself. For those of you with stock exhaust or slip-ons without a Ducati ECM (which is supposed to cure this problem) this is the solution I came up with. I just got back from a 30 mile ride and no CEL.

The main thing I learned is that by removing the cables... you get a CEL. By removing the pulley, you get a CEL. When you turn the key on the servo goes all the way one way and then back the other way, from what I can gather it does this to learn where the end-points are every time you power the bike up. Without cables or a pulley it will spin all the way around freely until it "times out" and the CEL comes on because it thinks a cable is broken. So, as long as the servo is stopped by something very closely to the same points it stops at when hooked up to the valve, it thinks everything is fine and it goes to the open position and patiently waits to mess up your sound and mixture around 3000rpm as usual.

Here is what worked for me...

I started by removing the the cables from the servo side of things, as long as the servo is all the way one way or the other you can pull down on the loose cable enough to slide it out of its holder and then disengage the cable itself from the pulley.

You can then manually turn the servo the other way using a large wrench on hex shaped outter end of it, I did this slowly as to not strip out the gears. **Make sure the key is OFF, if the key is ON the servo will not move and you will ruin it!!** After you turn it the opposite direction you can remove the other cable from the pulley.

After that I re-centered the pully so it was pointing straight up and removed it, hold it with a wrench, remove the bolt and you can pull it off by hand.

Next I cut a piece of aluminum flat stock and drilled a hole in the center and mounted it tightly to the shaft using a star washer on the back side and a lock washer on the front. Probably a good idea to put a drop of red Loctite on the nut too.

Make sure that when you put the aluminum (or metal or carbon or whatever you decide to use) piece on you make sure that the top and bottom edge of the flat on it are perpendicular to the flats cut on the shaft of the servo. The round sides of the shaft should be facing up and down respectively after the part is installed when viewing from the end of the shaft.

The idea is that the piece be long enough to come in contact with the plastic cable holding bracket on the bottom of the servo case, therefore stoping the servo at almost exactly the same point on each side, as if it were hooked to the valve.

Once the part is installed, I turned my key on to test it... if its out of position or wont let it go far enough one way or the other, you'll get a CEL before you even start the bike. I then turned the key off, made a small change and tried it again until I got no CEL. My CEL seems to reset itself after I turn the key off and wait a couple minutes.

Once I got this working correctly I took some small wheel collars from Radio Controlled aircraft/cars/helicopters etc... made by a company called Dubro and can be found at any hobby store, and cut a small groove on one side with a cut-off wheel in my dremel so I could slip it over the cable without cutting the ends off and ruining the cable, if for whatever reason I may want to hook it back up again I didnt want to have to buy new cables.

These have a small allen head set screw in the side of them for tightening onto a piece of metal rod or cable...

Once I notched the side, I pulled the slack out of the cables on the servo side and put these little guys on the cable above the mount to keep the cable sleeve from falling out of the servo mounting tab and rattling around under my fairings. The spring on the exhaust valve will hold the valve in the open position so pulling the slack out and putting these on basically ensure that the cables stay put. I suppose you could take them off at this point but seeing I wasnt sure if this was going to work, I left mine on.

Mine looks like this with the collars installed...

Here is a picture of it at rest with the key on, you can see the aluminum is almost resting on the plastic cable holder on the right side, this is what limits the movement, it hits the plastic and then springs back a touch. I hits the same spot on the other side, with a straight piece roughly this size these stop points are within a couple degrees of the cable stop points.

Only thing to watch for is that you dont make the part any longer than it needs to be or taller on the top sides opposite of what hits the plastic as it could contact the inside of the fairing once reinstalled through its course of movement if its too big. The servo will still move, thinking its opening and closing the valve while you ride but set up like this, it seems to trick it just fine and best of all, when done properly you should get no CEL.

My piece is a bit crude looking, I cut it out with a dremel and didnt finish it nicely because it was basically an experiment. Not that you can see it under the fairing anyways :)

The bike is throatier through the normal cruising rpm range of 3K-5Krpm with the valve disconnected and seems to run smoother while at a cruise in town within those rpm ranges. It also seemed to get rid of that little flat spot around the same rpm when accelerating from a stop.

If I find anything else worth noting I will update but so far all seems well! Exhaust vavle free! :)

49 Posts
Discussion Starter · #4 ·
DucatiGuy said:
And how does this mod effect your low end TQ figures with the stock head pipes? ... Considering the fact the butterfly is open at full throttle, I can't see you gaining anything much in terms of power on the long runs, but at part to mid throttle, is does a good job of burping the exhaust back pressure to help build more "usable" low to mid-end power, not to mention keeping the twin smooth. For street use, the butterfly is a godsend, but if you want to track your bike and are only after the mid to high-end spectrum, then a system without a butterfly is in your best interest...
I cant tell you what it does to the TQ figures as currently I have no dyno in my garage :) I can tell you that the bike runs smoother through the low-mid range revs now and there seems to be no flat spot in it. One of my buddies has a dyno in his shop but he wont let me put my bikes on it till he gets Eddie current, hopefully this winter sometime. The valve from my understanding is strictly for noise, its not a Yamaha. Yamahas Exup system works from idle to 9000rpm progressively opening through the revs.

The 1098's valve is open at idle, closes at 3000 and re-opens at around 5000... not for power, for noise in Europe. I like noise and unrestricted exhaust, I will have no "quiet valves" in my pipes.

So, for the most part, it makes me smile knowing its wide open all the time and my bike sounds better when cruising and its not sputtering and loading up at cruise rpm because my exhaust is plugged.
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