According to Ducati, the valve in the late model Monster mid-pipe is there to enhance low end torque, butt the popular thing to do is to remove it. So has anyone done a dyno run to see if this thing does what they say?
I have a 2009 M1100S with Leo Vince slipons, with dB killers of uncertain provenance. It is a little stuttery below 3 grand, which I am not surprised by, butt I wonder if removing the valve would exacerbate the situation.
I was first told that it maintains back pressure in the exhaust but after all the reading on this site the general consensus is that it is just there to reduce noise emissions. I removed the drive motor and cable but left the valve in place.
The valve closes off at idle to pass noise regulations... it defaults to open once you give it any gas. Feel free to take it out to clean up the looks of the bike... but finding a used 696 midpipe is basically searching for a white elephant at this point.
Current monsters run lean out of the factory to pass emissions... the only real thing you can do about it is to either reflash your ecu or put in a PCV in order to make a custom map for your bike.
Thought is correct assuming no late running production changes were made.
I wonder why no one is making a replacement mid pipe as is so oftern done for cat removal?
It dosen't seem like it would be that big a deal for a company that is already bending up pipes to make something like that.
Quote from: SpikeC on March 26, 2013, 03:51:13 PM
I wonder why no one is making a replacement mid pipe as is so oftern done for cat removal?
It dosen't seem like it would be that big a deal for a company that is already bending up pipes to make something like that.
Cats are in the stock cans for the new monsters so it's not needed, once you change to slip ons you've effectively removed the cats. the 696 midpipe mod is only for cosmetics and while it wouldnt be a bad biz idea to make them i'm not sure the majority of monster buyers notice the valve cover.
Sparks makes a midpipe, but not certain it fits the stock cans.
No is the short answer.
Quote from: SpikeC on March 25, 2013, 02:10:01 PMAccording to Ducati, the valve in the late model Monster mid-pipe is there to enhance low end torque
Not according to Ducati. According to some ill informed Ducati dealer sales personnel - I once had a sales guy telling me that was the purpose of the flappergate. Absolute bollocks of course [laugh].
As others have already said, it's sole purpose is to reduce noise emissions.
It functions only in the following circumstances:
Flaps closed/open at start up to confirm functionality.
@ 3000rpm* in neutral (this is where its used to conform with static noise tests in some jurisdictions).
It
never flaps closed when the bike is in gear..... so tell me how on Planet Reality it ever offers anything other than a minor restriction in your exhaust flow and the added weight/complexity of the servo motor to drive it.
Its removal will not lead to any great performance increase, but its presence is nothing but dead weight/ugliness.
Quote from: SpikeC on March 25, 2013, 02:10:01 PM
It is a little stuttery below 3 grand, which I am not surprised by, butt I wonder if removing the valve would exacerbate the situation.
Removal of the flapper gate will neither exacerbate nor improve the low end lumpiness. As
thought has said, modifying fueling is whats required to sort that issue.
Quote from: Raux on March 27, 2013, 12:50:39 AM
Sparks makes a midpipe, but not certain it fits the stock cans.
Sexy it is too [thumbsup].
* I think its 3000rpm but my memory isnt entirely reliable... could be 3500... 2500... but you get the point.
Thanks a lot for the info, now I get it! I'm starting to think that the Rexxer solution is looking more attractive!