Exhaust butterfly parameters

Jokeshopbeard · May 22, 2015

Does anyone know what these are? It seems like it's only open fully when you're near WOT...

Here's the million dollar question though:

Is it there for performance or simply noise reduction?

Cause if all it's doing is stopping the sweet sound of my V-Twin reaching my ears I'll have it off faster than you can say "Jack Robinson"..

Can anyone who has removed it comment on the effects?

Cheers!

kuksul08 · May 22, 2015

I once took off my muffler and watched it move while revving the engine. At idle it is open. As soon as you crack the throttle it closes. I believe it opens again after you reach a certain RPM.

It's for noise reduction only, I believe. I disconnected the cable on mine and now it sounds better and feels like it runs better at low RPM/throttle openings.

Jokeshopbeard · May 22, 2015

Brilliant. Thanks Kuksul - off it comes then!

zibbit u2 · May 22, 2015

Removing the plate does make the bike louder, and a little more free reving.. However it does reduce a little Tq down low, and you'll notice your exhaust will pop a little on decel.

Don't disconnect the cables, just remove the two little screws holding the plate on the shaft.. That way it won't throw a code.

Jokeshopbeard · May 22, 2015

Cheers Zibbit. Is it reversible if you remove these screws? I had fully intended to remove the cable to start, but if it's just as easy to remove the plate, I think I'll have a go at that..

kuksul08 · May 23, 2015

The screws on mine are welded on it looks like

GR8 · May 23, 2015

Can one of you guys do a before and after of the sound. If it works I might just take mine off too!

Pabst · May 23, 2015

I just disconnected mine after reading this, definitely louder through all rpm range and I could tell immediately, no codes but feels like less torque although it might be psychological after reading that it might, maybe in midrange and up?. it sounds great without being obnoxious, it sounds like a motorcycle now. I do not have any decel popping either. Just took off the two screws, removed plate and turned valve by hand so I could disconnect the cable, took less than two minutes. I read on an ebay sellers description that up to 2012 there is a module for no codes, he says 2013-2014 module not needed, so if you're buying one from somebody else they're ripping you off. It does sound waaaaay better and if you don't like it, it'll take just a minute to hook it back up. Here you go! Listen with good headphones or good speakers. :-D

BEFORE:

AFTER:

821torque2go · May 23, 2015

Thanks for that post. Great comparison. Cheers

willmac · May 23, 2015

Pabst said:
I just disconnected mine after reading this, definitely louder through all rpm range and I could tell immediately, no codes but feels like less torque although it might be psychological after reading that it might, maybe in midrange and up?. it sounds great without being obnoxious, it sounds like a motorcycle now. I do not have any decel popping either. Just took off the two screws, removed plate and turned valve by hand so I could disconnect the cable, took less than two minutes. I read on an ebay sellers description that up to 2012 there is a module for no codes, he says 2013-2014 module not needed, so if you're buying one from somebody else they're ripping you off. It does sound waaaaay better and if you don't like it, it'll take just a minute to hook it back up. Here you go! Listen with good headphones or good speakers. :-D

BEFORE:

AFTER:

It says your video clips have either been moved or deleted ?

Pabst · May 23, 2015

Weird, try this?

BEFORE

http://vid1293.photobucket.com/albums/b581/phlub/IMG_7009.mp4

AFTER
http://vid1293.photobucket.com/albums/b581/phlub/IMG_7008.mp4

willmac · May 24, 2015

Pabst said:
Weird, try this?

BEFORE

http://vid1293.photobucket.com/albums/b581/phlub/IMG_7009.mp4

AFTER
http://vid1293.photobucket.com/albums/b581/phlub/IMG_7008.mp4

Cheers Pabst.
Worked great this time.
Best comparison sound vids I've come across. You can clearly hear the difference.

Is it as simple as removing the screws, or is there a back up spot weld you have to deal with also on the screws ? As I'm sure I read somewhere on Ducati.ms that they mentioned there was weld there to stop screws backing out under vibration ?

Pabst · May 24, 2015

Nope, no welds on mine, it was really simple, no loctite either. It literally took under a minute. I think they might be talking about the actual valve? I'm just removing the cover plate screws and disconnecting on cable for the valve, similar to removing the cable to bicycle brakes, just turn the valve by hand until there's slack and put the cable out of the slot.

Pabst · May 24, 2015

zibbit u2 said:
Removing the plate does make the bike louder, and a little more free reving.. However it does reduce a little Tq down low, and you'll notice your exhaust will pop a little on decel.

Don't disconnect the cables, just remove the two little screws holding the plate on the shaft.. That way it won't throw a code.

I don't understand this, the two screws I found are just for the cover plate covering the valve and cable and they won't do anything except expose it so you're able to disconnect it. An ebay seller of the modules to prevent throwing codes says 2013-2014 Hypers will not throw a code if the cable is disconnected, mine hasn't thrown one yet. I'm not actually removing anything, just the cable.

kuksul08 · May 24, 2015

Pabst said:
Nope, no welds on mine, it was really simple, no loctite either. It literally took under a minute. I think they might be talking about the actual valve? I'm just removing the cover plate screws and disconnecting on cable for the valve, similar to removing the cable to bicycle brakes, just turn the valve by hand until there's slack and put the cable out of the slot.

Ohhhh yes, I see what you're talking about. The 2 screws you're referring to are for the cover for the rotating cable mechanism. The screws I was referring to are the ones holding the flapper valve onto the pivot inside the exhaust pipe. The latter are welded on IIRC. So it's easiest to simply disconnect the cable.

zibbit u2 · May 24, 2015

The two screws I was referring to are accessed after you remove the rear slip on (inside the pipe) that hold the flapper plate. Yes they're spot welded, so use a dremel tool and a grinder wheel or cutoff wheel and remove the spot weld.. After that unscrew them and remove the plate. Before you install the slip back on, start the bike and it'll blow any shavings out of the pipe (warning it'll be loud). Then reinstall the slip on. Total time to complete the job is about 15 minutes.

If you disconnect the cables, it'll throw a hidden error code. Removing the plate and leaving the cables alone doesn't have any errors associated with it.

zibbit u2 · May 24, 2015

Here's a good link which shows the procedure.. Look at post #2

SC-Project CR-T Exhaust Install - Ducati.ms - The Ultimate Ducati Forum

Pabst · May 24, 2015

Oh, okay, now I see the two screws. Thanks.

Exhaust butterfly parameters

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