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Discussion Starter #1
Is there a procedure on how to increase idle? I looked in the workshop manual, forum and online and couldn't find anything.

I had the bike into dealer couple weeks ago because of stalling issue. They found some linkage was bad, which it solved the problem on my 160mile trip back home. However when I had the bike out today it did same thing, stalls when coming to a light (sometimes). When idling it is at or below 1k and I am thinking this would help some. Bike has 6000 miles, belt/valves about 1k ago and full termi system. Thanks.


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You can't adjust idle alone; it needs to be done along with fuel trim. Three conditions must be met at the same time for the bike to run good:
1) idle speed at 1250RPM
2) balanced throttle bodies (both and idle via the bypass screws and at ~3000 using the throttle linkage)
3) CO between 4% and 6%

All 3 must be adjusted once the TPS has been properly zeroed (that has it's own precedure since you actually need to set the throttle butterfly at 2.33 degrees).

To adjust the TPS I do as follows:
1) back the throttle cam stopper screw all the way
2) zero (i.e. set to 2.33 deg) the TPS using ducatidiag (now you basically have the butterfly physically at 0 and the ECU at 2.33)
3) turn the cam stopper screw until you read 4.66 on the ducatidiag (now the butterfly is physically at 2.33 and the ECU thinks is at 4.66)
4) zero the TPS again (now both physical position and ECU reading are the same)

To increase or decrease the air intake at idle, there are two bypass screws on the TBs that you access from the left side of the airbox (on US version they are technically blocked off, but you can pop off the cap easily; you can order the Euro style rubber caps that are much simpler to put on and off). Air intake, of course, is only one variable controlling idle speed (the other being fuel trim).

You need to have some kind of device connected to TBs when turning the bypass screws to ensure you keep the TBs balanced (i.e. the vacuum is the same). Since you don't need to know the vacuum, all you care is that the same, you can make your own device by running a hose around a stick, put in some liquid, connect each end of the hose to a separate throttle and turn the screws until the liquid is leveled. Something like this...



To balance the TBs at faster speed you use the fast idle control and balance the vacuum adjusting the throttle rod.

To measure CO you need an exhaust analyzer and ducatidiag to adjust the trim. The analyzer cost around 200-250 buck new...

This is way more than any dealer would do (unless you ask and pay for it), but it gurantees you'll have a smooth as butter running bike that doesn't stall.

Now, doing some research in the past about the 749, I learned that the stalling issue at idle has to do with the cam overlap. I would suspect that upon complain to a dealer, he try to mask the issue by tweaking the fuel trim. The proper procedure involves correcting the cam timing. I was reading on BikeBoy tht Ducati themselves have a revised cam timing for the 749.

I know this is probalby more than you asked, but long story short, there isn't just a simple screw you turn: low idle is caused by an incorrect tuning.
 

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Discussion Starter #3
Great feedback and much appreciated.


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You can't adjust idle alone; it needs to be done along with fuel trim. Three conditions must be met at the same time for the bike to run good:
1) idle speed at 1250RPM
2) balanced throttle bodies (both and idle via the bypass screws and at ~3000 using the throttle linkage)
3) CO between 4% and 6%

All 3 must be adjusted once the TPS has been properly zeroed (that has it's own precedure since you actually need to set the throttle butterfly at 2.33 degrees).

To adjust the TPS I do as follows:
1) back the throttle cam stopper screw all the way
2) zero (i.e. set to 2.33 deg) the TPS using ducatidiag (now you basically have the butterfly physically at 0 and the ECU at 2.33)
3) turn the cam stopper screw until you read 4.66 on the ducatidiag (now the butterfly is physically at 2.33 and the ECU thinks is at 4.66)
4) zero the TPS again (now both physical position and ECU reading are the same)

To increase or decrease the air intake at idle, there are two bypass screws on the TBs that you access from the left side of the airbox (on US version they are technically blocked off, but you can pop off the cap easily; you can order the Euro style rubber caps that are much simpler to put on and off). Air intake, of course, is only one variable controlling idle speed (the other being fuel trim).

You need to have some kind of device connected to TBs when turning the bypass screws to ensure you keep the TBs balanced (i.e. the vacuum is the same). Since you don't need to know the vacuum, all you care is that the same, you can make your own device by running a hose around a stick, put in some liquid, connect each end of the hose to a separate throttle and turn the screws until the liquid is leveled. Something like this...



To balance the TBs at faster speed you use the fast idle control and balance the vacuum adjusting the throttle rod.

To measure CO you need an exhaust analyzer and ducatidiag to adjust the trim. The analyzer cost around 200-250 buck new...

This is way more than any dealer would do (unless you ask and pay for it), but it gurantees you'll have a smooth as butter running bike that doesn't stall.

Now, doing some research in the past about the 749, I learned that the stalling issue at idle has to do with the cam overlap. I would suspect that upon complain to a dealer, he try to mask the issue by tweaking the fuel trim. The proper procedure involves correcting the cam timing. I was reading on BikeBoy tht Ducati themselves have a revised cam timing for the 749.

I know this is probalby more than you asked, but long story short, there isn't just a simple screw you turn: low idle is caused by an incorrect tuning.
Nice write up, just a few points that needs attention.
You will find out that having negative pressure and CO emissions on both cylinders balanced can be a bit tricky, (a flow matched pair of injectors certainly helps). Therefor a compromise should be made in favor of a balanced CO percentage, difference should not be greater than +0-5%CO.

After the TPS reset you need to balance the negative pressure of the throttle bodies, a DIY vacuumeter with some two stroke oil in it (in case it sucked up) will work just fine since absolute value is not important, even same level between the two columns is not important (it might change as you adjust), what is important is to see the two columns raise simultaneously when you blip the throttle.


http://www.natenewz.com/2010/06/13/carburetor-tuning-with-diy-manometer/



To balance negative pressure there is no need to mess with the throttle connecting rod, there is a Balancing Adjuster Screw (21) for this purpose.

1. Reset TPS
2. Close both By-Pass Screws (20) all the way in (engine will not idle), measure how many turns they went in.
3. Start engine, run it to 3000-4000rpm
4. Balance negative pressure with the Balancing Adjuster Screw (21)
5. Open By-Pass Screws (20) to their original position, adjust if needed in 1/8 steps (both screws the same amount and same direction) to have an idle speed between 1200-1300rpm.
6. Connect Gas Analyzer on rear cylinder and adjust Trimmer with DucatiDiag to 4% - 6%CO, if idle speed changes re-adjust By-Pass Screws in 1/8 steps (both screws the same amount and same direction) to have an idle speed between 1200-1300rpm. Make a CO% reading. (say 5%CO)
7. Connect Gas Analyzer on front cylinder and adjust only the front By-Pass Screw so that you get the same CO% reading as the rear (say 5%CO), DO NOT USE DUCATIDIAG TRIMMER ADJUSTMENT ON THE FRONT CYLINDER, DUCATIDIAG TRIMMER AFFECTS BOTH CYLINDERS.
 

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Very good addition! Thanks.

I adds couple of extras that came to mind reading your post.

As a preparation to the tune up, I normally run a tank with a full bottle of Redline S1 fuel cleaner. This is a very concentrated dosage and gets injectors and valves pristine. Consider also that shower injectors are a lot less prone to carbon deposit since they don't hear soak as much. It's hard to get them perfectly balanced but this way you're 90% there.

As far as the balancing works, I actually prefer start balancing the throttle rod and only later use the bypass. The problem with the bypass is that they become less and less influential as the throttle angle increases. Checking balancing at higher throttle angle helps a lot in smoothing power delivery. A good balance at idle helps in cleaning the transition from off to on throttle.

One last thing: good valve clearances and a diales in cam timing also contributes in making vacuum and CO balancing more accurate and uniform.

It is a combination of multiple factors and the more precise you are the better the engine runs. Particularly a lumpy twin with aggressive cams...

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Discussion Starter #6
Question as I have digested all of this.

I see that the idle is adjusted via the two screws (20) in the diagram. When I am adjusting the CO level, is it strictly and only adjusted via ducatidiag trimmer? Then the idle has to be readjusted again because it may be effected by the trimmer adjustment?

Do you use only the trimmer because US bikes don't have CO adjuster screw as mentioned in the workshop manual?

For a street bike, is it better to target a 4% CO or what is a good target?

I had the bike into the dealer couple weeks ago and the throttle adjustment / synch was done. This cured me on the way home but I am stalling again. I am thinking of going through the TPS (once cables arive), idle and CO adjustment on my own. I can't screw things up to bad can I?
 

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This is excellent, one of the best articulated "Do-it-yourself" problem solving guides to the Ducati 999/749 probably any model, stalling issue.
Thank you guys!
 

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Discussion Starter #8
I think last questions for now, along with one above.

1 - is the actual value for throttle open suppose to be 2.3 degrees? Reading the following article it shows the 749 is 1.3 degrees. http://bikeboy.org/ducatitps.html

2 - I have read some other replies on here that people say it is a quick job, is that because they just reset and do not remove air box to ensure throttle connections are loose and plate is against stop?


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Question as I have digested all of this.

I see that the idle is adjusted via the two screws (20) in the diagram. When I am adjusting the CO level, is it strictly and only adjusted via ducatidiag trimmer? Then the idle has to be readjusted again because it may be effected by the trimmer adjustment?
Basically each adjustment affects the other, if you adjust the DucatiDiag Trimmer it will affect CO emissions and Idle speed, if you adjust the By-Pass Screws it will do the same, it's a bit tricky as you need to go "back and forth" adjusting but not difficult overall.



Do you use only the trimmer because US bikes don't have CO adjuster screw as mentioned in the workshop manual?
I assume you mean By-pass screws.
US bikes falls under an emission regulation law that don't allow adjustment of the By-Pass screws, that of course doesn't mean that they don't have them, they are plugged with "tamper-proof" :rolleyes: plugs that you can either pop-off or drill-out.

For a street bike, is it better to target a 4% CO or what is a good target?
4%CO is a good starting point.

I had the bike into the dealer couple weeks ago and the throttle adjustment / synch was done. This cured me on the way home but I am stalling again. I am thinking of going through the TPS (once cables arive), idle and CO adjustment on my own. I can't screw things up to bad can I?
It's a "straight forward" procedure, and fairly easy one IMHO.



I think last questions for now, along with one above.

1 - is the actual value for throttle open suppose to be 2.3 degrees? Reading the following article it shows the 749 is 1.3 degrees. BikeBoy.org - DucatiLinear Throttle Position Sensor setting notes for all models 08/08
The actual value of the throttle when you "reset" it depends on the loaded fuel maps first value in the degree row.

2 - I have read some other replies on here that people say it is a quick job, is that because they just reset and do not remove air box to ensure throttle connections are loose and plate is against stop?
It can be a quick job, the second time that is.:D
Throttle connection rod rarely needs adjustment and most likely will stay in place for the bikes life, it will only need adjustment if you split the bodies.
 

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Most of the open questions have been answered, but I just want to reiterate a couple of things.

#1 US bikes have bypass screws just like everyone else. It's just the access plugs on the airbox that are not as simple to pop off. With left runner and filter removed you can go in with your hand and push it out. If you go on the Ducati website and download the non-US parts manual you can find the part number for the Euro plugs and order them from the local dealer.

#2 Resetting the TPS is as simple as pushing a button on ducatidiag, but that's not the point. What you're doing is ensure that the physical position of the butterfly is what the ECU reads. That's why I go through the process I described. Let's remember that fueling is done on an alpha-n map which means the injectors timing is done by reading butterfly angle (alpha) and engine speed (n). If any of the two parameters is incorrect the injectors stay open too little or too much and you get a wrong trim. And this leads to...

#3 the throttle rod. There is only one TPS and two throttle because the system assumes the throttle bodies are balanced. At idle you balance it with the bypass screw for a very fine tune. Off idle you use the rod. If you're doing the tune yourself and you're trying to be anal, check the vacuum off idle as well, set it around 3000-4000 RPM using the fast idle lever or having someone holding the throttle.

#4 what CO level... WITHIN CERTAIN LIMITS a lower CO makes the engine more crispy while a higher makes it smoother. It's important the caveat of within certain limit. If you've ever ridden a stock 1098 or so with the trim set at 1.5% you probably noticed how the on-off throttle is not smooth, how the bike pops upon decelerating. That's good for emission but affect riding quality. That said a better baseline for me us 5% which is in between the 4 to 6 recommended by Ducati for performance. And by the way, that trim level is what an engine should ride at if it wasn't for government regulations.

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For the owners of US models, you can order the Euro removable rubber idle adjustment covers. Your dealer should be able to get them or order them from overseas yourself.
 

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Discussion Starter #13
ZetaTre (and the forum), thanks for all the feedback to help my stalling issue. Rode the bike to ECS yesterday and got all three of these things done: TPS reset, idle adjusted from 1000 - 1450 and CO increased (trim from -14 to +24). The bike is actually running now when you are at a stop sign!

Also if your in the southern NY area looking for a shop, ECS is great
 

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ZetaTre great info.:yeah:
 

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What about bikes with a lambda sensor? I think my bike has one because nothing seems to happen when I change the fuel trim-- no change in idle speed. Do you need to disable the lambda sensor before setting the CO? How? Thanks!
 

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I have little to no experience on motorcycles with lambda feedback, but I have a few pointers you might want to look into.

For example I know that JPL's writer (that's the coding software you can license from the same developer of ducatidiag) allows you to disable the lambda feedback. What the implication of that are, I don't know. I'm not sure whether it just removes the check engine light or actually defaults back to some value that can be adjusted.

I would also think that full systems for those bikes have no lambda feedback and since the ECU it's the same hardware, just different maps, I would think it handles trim some other way... again a hint to some value controlled by the operator.

I hope this helps a bit...

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I have little to no experience on motorcycles with lambda feedback, but I have a few pointers you might want to look into.

For example I know that JPL's writer (that's the coding software you can license from the same developer of ducatidiag) allows you to disable the lambda feedback. What the implication of that are, I don't know. I'm not sure whether it just removes the check engine light or actually defaults back to some value that can be adjusted.

I would also think that full systems for those bikes have no lambda feedback and since the ECU it's the same hardware, just different maps, I would think it handles trim some other way... again a hint to some value controlled by the operator.

I hope this helps a bit...

Sent from my SGH-T679 using Motorcycle.com Free App
Thanks! I gave JPL an ecu dump and he said the lambda sensor was not active on my bike. The idle speed is mainly set by the bypass screws. Next question: how is the balance adjuster screw accessed? Does the top of the airbox have to be removed?
 

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Thanks! I gave JPL an ecu dump and he said the lambda sensor was not active on my bike. The idle speed is mainly set by the bypass screws. Next question: how is the balance adjuster screw accessed? Does the top of the airbox have to be removed?
Great thinking about sending your dump to JPL!!!!

I believe there's two components in the bike: there's an automatic bypass valve which I believe works alongside with the lambda.

Additionally there's two bypass screw on the TB, just like other bikes.

They are accessible with the airbox on: the procedure requires the bike to be running and the Testa Evo have the injector mounted on the top of the airbox...
 

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What info and thanks although I'm new to these bikes and have no clue what most of this means. I live very close to Oceanside. Is there a place locally that I can have my stalling issue resolved? I'm in San Clemente.

Most of the open questions have been answered, but I just want to reiterate a couple of things.

#1 US bikes have bypass screws just like everyone else. It's just the access plugs on the airbox that are not as simple to pop off. With left runner and filter removed you can go in with your hand and push it out. If you go on the Ducati website and download the non-US parts manual you can find the part number for the Euro plugs and order them from the local dealer.

#2 Resetting the TPS is as simple as pushing a button on ducatidiag, but that's not the point. What you're doing is ensure that the physical position of the butterfly is what the ECU reads. That's why I go through the process I described. Let's remember that fueling is done on an alpha-n map which means the injectors timing is done by reading butterfly angle (alpha) and engine speed (n). If any of the two parameters is incorrect the injectors stay open too little or too much and you get a wrong trim. And this leads to...

#3 the throttle rod. There is only one TPS and two throttle because the system assumes the throttle bodies are balanced. At idle you balance it with the bypass screw for a very fine tune. Off idle you use the rod. If you're doing the tune yourself and you're trying to be anal, check the vacuum off idle as well, set it around 3000-4000 RPM using the fast idle lever or having someone holding the throttle.

#4 what CO level... WITHIN CERTAIN LIMITS a lower CO makes the engine more crispy while a higher makes it smoother. It's important the caveat of within certain limit. If you've ever ridden a stock 1098 or so with the trim set at 1.5% you probably noticed how the on-off throttle is not smooth, how the bike pops upon decelerating. That's good for emission but affect riding quality. That said a better baseline for me us 5% which is in between the 4 to 6 recommended by Ducati for performance. And by the way, that trim level is what an engine should ride at if it wasn't for government regulations.

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For 749 TPS value is 1.3
Personally I don't understand what is about negative pressure adjustment.
 
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