Ducati Monster Forum

Kamna have a servo valve delete pipe for nearly 300 €! I was thinking of utilizing my local custom exhaust shop to cut n shut the oem section of pipe with the servo valve. I gotta find a used pipe for the job.

Anyone done this or have some links?

Cheers.

I just waited patiently for one to spring up on eBay...  (EDIT:  Actually, I think it was one of the salvage guys on FB with a wrecked 696... )

http://www.vizi-tec.com/duc-ee/

Thanks Carlos. [beer]

I will conduct a simple test with a Smartmoto Servo Eliminator under controlled conditions. It appears the default position of the exhaust valve (which I'll call an Exup) is open via spring pressure, so the connection of a device to the Exup servo motor loom will leave the valve open. A simple test.

According to Smartmoto the valve not only restricts noise, but helps manage and even out the torque in a big twin by reducing (thats right) reducing the maximum torque available at lower revs making the bike easier to ride. If this is true, this is the opposite effect of Exup valves for inline fours and my experience with YZF Exup bikes. I found the low rpm torque of my HM1100Evo with full system sans Exup and the same level of tune to be quite savage (just the way I like it). The M1100Evo's low rpm torque with Exup is quite civilized in comparison.

I will test this and report back.

Yes, the valve is open by default.  I installed a Duc-ee on mine and removed the servo motor.  One of these days I'll get under there and swap out the middy pipe for the 696 version.

With the 796, I couldn't really tell any difference with or without the flapper working... but the idea of it just bothers me.  I researched it a bit and, basically, you have to destroy the pipe to get the actual flapper out... hence the 696 pipes popularity.

Nothing lasts forever... and I would hate to have the spring fail on a ride...

Tested the servo eliminator. I just fitted the device to the loom after disconnecting the servo motor, but left all components in place making it easy to revert back to the stock set up for the street.
While the exhaust noise increased a little it was much less than expected, with a deeper and less raspy tone. The deeper tone although being a little louder, was less intrusive. Overall noise was further diminished by a very noticeable reduction in intake noise. It is not a case of the exhaust note drowning out the intake noise as the intake note is louder than the exhaust at certain throttle openings. The only explanation I have for this is that when the servo valve was operative it caused reversion through the system at certain throttle openings which manifested as excess noise at the intake opening.

From the riders seat the bike is now quieter to ride, an unexpected result.

Now to core business, the part throttle/low end torque has increased with greater engine response at small throttle openings. [thumbsup]
Edit: I think l was partly wrong on this. Right off idle torque was softer. See post below after further back to back tests.

http://www.ducatimonsterforum.org/index.php?topic=77503.msg1427285#msg1427285

Anyone deleted or deactivated the exhaust exup valve and if so, was there a benefit? Any dyno evidence? My back to back testing on two bikes gave me the impression as per the above link.

Would love to be able to tune it to open at the desired portion of the map and at the desired rate. It really did smooth and increase bottom end torque, but caused mid range hesitation when operating.

I have left it disengaged, but have closed down the air bleed screws an even amount on the TB's from 1/2 to 1/4 turns from the factory setting for more and smoother bottom end torque. The bike is now fully open loop so the air screws should effect idle/low rpm mixture without harming idle speed which is handled by the stepper motor. Never thought I'd be happy about a stepper motor, but in this case I am.

Any thoughts on this?

I need a dyno for Christmas.

koko, I performed this mod to a few Ducs while at the dealership here in Panama, the customers that reported 'a noticeable change in characteristics' were the MTS1200[in general] owners, the Diavel owners said they loved the change but not the 'extra noise'

PITA to get all parts out of exhaust since I do not trust any exhaust shop to weld a piece instead of the OEM material and no one wanted to dish out the $ for the OEM style headers without the valve's location but O2 sensor mounting locations, performed recently on a Monster 821 where I also replaced the 'headers' which I didn't like the construction quality, something 'not matching my expectations' about them and owner stated he felt a difference and it was a little louder all around. He already had the Termi slip ons and Ducati performance tuning that came with the Termis, yes I performed that job back in 2015 or so but the valve motor had quit and for some reason did not kept it open so he decided to go this way

So it seems to be 'a personal appreciation' of before and after  .. .. .. I think

Thanks mate. That sounds right. I liked the Exup at low speed and hated it on the highway. If the neighbours complain I'll connect it back to stock. [thumbsup]

My only experience with it has been on Ducati, so, cannot say a word on Yamaha

Throttle body air screws make a difference to low % throttle position tune when the system is converted to full open loop by whatever means. Useful, not only for idle synch, but small throttle operations difficult to emulate on a dyno. I am currently tuning for no Exup valve and the gigantic velocity stacks sans airbox. Very useful.

The valve also definitely closes around the 3000-3500 rpm mark. That would be about 100kmh/60mph in 6th gear, so Im guessing that helps with the ride by noise test. Gently raising the revs, you hear the exhaust suddenly go quiet at that rpm range then louder again once its past it at around 4000rpm or so.
Pity someone doesnt make a tunable device that turns it into a true Exup valve, then you could run bigger cams and an even larger diameter pipe and have the valve open gradually.

Just one question koko, are you testing on the M1100 or another bike? Just want to be sure.

I do know that tuning softwares have either a "SET" or "DELETE" and one has an "OFF" where you leave it all as is but will just leave valve open.

Issue with this valve is not the motor itself, are the plastic gears inside; I know that one is working on software to use it for its advantage and even making it 'backwards compatible' to help with 'throttle modulation' . . . And that is as far as I can go with this info. No word if this software will be made public with some hardware or will work on a 'core exchange(ECU)' basis

On an M1100Evo. [thumbsup] . I have a Smartmoto device that deactivates it, leaving it open.

Koko, do you really think the valve has a value to performance beyond the SPL driveby?  I understand the Yamaha EXUP setup, but I don't know if the Ducati valve would lend itself to a functioning (adjustable rate) valve like EXUP.

I guess it's all in the software and they could do it if they really wanted to. As it is, it clearly just functions to cheat the db test. It does smooth  out torque fluctuations a little and more so with major intake mods but at a cost IMO. I like the aggressive nature of the torque build up. It's exciting, fun and not too civilised. I've left it off with the delete device because I wanted to get away from that cv carb feeling. I actually have it tuned quite smooth down low so it's ok. I would like to delete the valve and have the pipe crossover without a gap like the 900's. That would take some cut n shut work and more Dyno time, but worth it I reckon. So I'm thinking a 2 into 2 with genuine X crossover rather than 2 into 1 into 2. I'm looking out for some parts to get that project started. Kaemna have a set of link pipes to achieve that but at around 550 Aud plus tax and shipping. Damn our Pacific Peso.

So, you are talking true duals, or is there a balance pipe between them?

TBH, I don't miss the flapper... at all.  Maybe I'm missing it, but with my 796 and the replacement cans it's all good and no bad.  Granted, I pulled the cable and servo completely out, so I can't test it with/without the flapper, but I don't think there would be much of a difference.

Definitely a crossover more immediately before the mufflers. I've settled for no flapper too and tuning for that now.