amazing, huh?

who'd figure something for free would actually work???

I found that the bike actually got BETTER as time progressed. I can't quite work this out but it's much smoother than my 900SS now - and both were similar before the ciggie butt.

The mix screw (pot) on the ECU really only affects idle mix - it doesn't do much at cruise speeds and does nothing on acceleration.

I'd be pleased to get any feed-back... and you can send donations to the Laddie Foundation - Fund-a-Cure for 907's; these are tax deductable if you have a good accountant...

Mine works flawlessly now after winter renovation/check of heads, injectors & electrics, new pistons,
+ original exhaust system mounted.

Hi again,
Late getting the bike out this year. Instead of the cigbutt I placed a much thinner tube inside the rubber hose at the sensor. It wil slow the air speed as well as the cig. The tube used was left over from my scottoiler accessories. Anyway to seems to work, or maybe its something else I done that have kept the problem away.
When I did my Spring work I did find slight corrosion in the plug/socket of one of the Ignition Modules that sits on the aluminum plate where the relays and the Regulator are also mounted.
Looking forward to Assen TT in a weeks time and (pray) that the problem is now gone again.

Enjoy you Summer - or Winter riding if you're from Aus.

Rasser
(Per

Probably find a small inline fuel filter will have the same effect

See my other thread on misfiring. I did some testing on the ciggie butt vs a restriction made from a lead pellet. The smallest drill I could find is a #60 (.039") and Laddie thought that bled down too quick, about 2 seconds. Putting the entire ciggie butt into the line may be too restrictive, mine was 15 seconds. It needs to be somewhere in between.

Count me another happy customer. For the record I used about 3/4 of a ciggie butt in the tube (thats 3/4 of the thickness, not of the the length). There was an improvement noticeable immediately even just in the ability to hold a steady 3K rpm in neutral (although not rock steady) and on the road it's like she is a different machine. Poking about at the speed limit in the 2800-3500 rpm range is now just boring... as opposed to boring, frustrating and occasionally scary!

This really has made a difference to her tractability around town and I for one want to thank Laddie for coming up the idea...Top stuff mate!

Cheers
Andrew

after reading ALL of the above, I called a meeting of all the local experts and other knowledgable persons and after lots of constructive conversation, ground breaking idea's , and the perusial and consultation of several technical manuals we have come up with a soloution to your dilema Put a !@#kin webber on it !! ( shouldn't be hard to find one ha ha ha )

of course sheep can ride, you can teach them other tricks too ??!! but seriously ( I am not at all familiar with the 907 ) you talk of the cigerette butt up the vacuum sensor tube to dampen the vacuum pulsing ,( this does make sense to me ) , On my 906 there is a vacuum tube from BOTH intake manifolds ( via a tee connector ) that goes to the webber marelli digiplex magic box, does the 907 vacuum tube connect to just one manifold or both ? maybe being connected to both manifolds would " average out " the pulsing effect . I cant for the life of me figure out how any electronic sensor could make sense out of such a wildly varying / pulsing vacuum signal, but then Im not Itallian! good luck
ps I do like that ciggy butt idea your not part kiwi are you ?

Oh McTool, you've done it again...

The 907 vacuum tube connects to the air box - so not quite the same severe fluctuation as an intake manifold...even though the pulse time is low frequency at idle.
Probably the reason the 907 idles like a charm is the pulses in the air box are quite small at idle because the throttles are nearly shut.
This is the converse to using vacuum on a "conventional" intake manifold - the vacuum is highest with shut throttles Perhaps the air pressure has little or no effect on the ECU map at low RPM. I dunno. I have been hoping some expert will chip in and explain the algorithm.

The erratic misfire appears to only occur at partial throttle settings...and my guess is that is because the air box pressure fluctuations are highest and still relatively low frequency...
Temperature has something to do with it...the misfire is generally only present when the engine temp exceeds 80 degrees...

The misfire is gone in most cases above 5000 RPM - so I assume the pulse frequency is high enough to cause a smooth reading at the sensor. maybe the vacuum fluctuation is smooth enough to give correct operation?

Also, the misfire disappears on even slightest acceleration under load - so maybe the ECU is responding to the changes in the TPS over-riding any signals from the air sensor.

whatever the cause for the bad behavior the ciggie butt seems to filter it out at all temperatures and right thru the rev range.
You can see feedback from some that the ciggie butt worked (or improved) to cure the misfire. I know I personally spent big bucks chasing a problem that wouldn't go away with new components or any amount of tuning...

I often wonder how much others have spent on the problem and how many 907s have been abused ot pensioned off because of this misfire. It's obviously quite common. It nearly drove me insane. (maybe it did)

New Zealanders may prefer to stuff some wool from their favorite girlfriend in there; I'd suggest 18 micron super-fine Merino..we wouldn't want some scratchy, coarse old Suffolk or Lincoln fibres in the precision mechanicals of a 907.

I prefer to stick to the ciggie butt as the component of choice because I'm sure it will give the much maligned tobacco companies a sense of pride to know that a bi-product of smoking actually cures something.

Hi Laddie What did I do again ?, If you mean missing something vital.... Yeah I'm still learning ( and am happy to be doing so too ) and thanks for the explanation ,I have a better idea now of how the thing is supposed to work . Does the fuel injection and the ignition run of the same computer ? These things can be very frustrating to cure and as there is more than one 907 playing up one would think that it an idiosyncracy ( spelling ? ) of the bike , but then these things are not magic , so there must be a reason . As you will no doubt know the webber on the paso 906 is far from perfect , although , with a lot of mucking round I have improved mine, but at the end of the day I just had to learn to live with it , and any how it is really only a pain in the ass round town
Andrew B , man did I ever get it in the neck when I got home, according to the Mrs the correct answer to your " #@$k me , I didnt know sheep could ride " is " sure they can ! has he not heard of Jonh Britten , graeme Crosby , Shaun Harris , Robert Holden , Andrew Stroud........... who is this guy ? bet he's an aussie. All in good humor of course. Good luck with the search for the cure , I will follow this issue with intrest

Hi

Found another reason for the misfire-at-cruise problem in my 907 1993.

I hoped to fix the problem using Laddies' "cig butt mod" but found out that the connection fitting of the presure sensor had a small crack allowing gas leakage and deviant presure figures to the ECU. I fixed the cracked connection with 2 component epoxy glue and the misfiring problem disappeared, I didn't dare to hope for such a simple solution but it worked definitely.

Laddies' "cig butt mod" used to cure other 907s MAY have flatten sharply oscilating presure values originating from gas leaks somewhere between the air filter and the presure sensor. Sounds fine, but what would be the reason for the DUCATI (or is it Cagiva) engineers to fit a sensitive pressure sensor in the first place?

Check fittingss, the tube and the air filter housing for gas leaks. And remove the sig butt wehn found

George

...OK; I guess that "fixing" a broken sensor is a "fix" in itself...
but I do have one really really good question...

How did you test the MAP sensor worked after you glued it to fix it?
did you apply a vacuum? if so - what pressure?
are you sure the MAP sensor is still working (not blocked?) If it's blocked you won't have a problem - it won't fluctuate AT ALL.
I'd be interested if you connected it to an oscilloscope (like I have) to observe the output fluctuations real time.
Don't tell me you did it with a fluke or multi-meter; they don't have the reaction time.

before you discard the ciggie butt theory you need to understand the air box pressure/vacuum dynamic (and anomalies between bikes)
under acceleration (open throttle) the air box vac is significantly different to at cruise...add any misfire (or backfire) and the pressure "spike" in the box is directed to the sensor; the filter slows the sensor reaction rate.
in a perfect world - with perfect timing and gas mix and tune there should be no need for the filter...but if there is a misfire the filter de-sensitizes the signal to the ECU and keeps the engine more stable. Kind of like a flywheel...

Wow, all vacuums suck I reckon, I used an alcorythm to find out how my dope worked and when i tried to use my multimissus she wouldn't have a BAR of me. Hardly suprising given that her MAP sensory device was blocked. It was then that I thought that her sensor reaction rate was not going to participate in my perfect world. Things really are grim on the home front. I think I will get me one of those mail order sh... woops ,,,brides from the Far Eastern Islands to the South.
As the weather is warming up now in good old Tassie, (almost peaking at 12 degrees coldius,) it may be time to drag out the 907 and see if I too can invoke the misfire of wrath , as I have been feeling a little left out, .................
though I have always dun my own toonin of me sickles, and neva had a spot of bovver.
Down here on the wet coast we have experienced abnormal rainfall this year and have had almost 4 metres of rain as opposed to our normal 3.9 metres. Thats how you become adept at understanding how fickle a sickle can be. Months in the shed delving relentlessly ,checking and rechecking trying to find something wrong with my bike . A fruitless excercise fraught with an inherent undercurrent of self loathing, unable to pinpoint "THE PROBLEM". Its a real bastard not having anything to fix.
Aint life fun....

"To be continued'.......Marty