High idle speed - 1200 Sport

[ohiorider]

What's worse --- this issue or an oil thread? :mrgreen:

I am aware the stepper can be totally disabled by using either an in line valve in the hose between the stepper and the airbox (or simply plugging it 100% of the time), but my bike seems so close to operating properly, I would like not to noodle with the stepper motor. It would make sense, I'm sure, to plug the hose and see if the engine does stay at 1100 RPM once warm. If that cures the issue, well, it'll be time to install either Todd's electrically controlled switch or a manually operated valve in line with the hose and quit fighting it.

Is there an adjustment one can access to change how the stepper motor actuates the throttle butterflies? Obviously, I'm NOT mucking with the 'sacred screw.' I've taken the advice of one of the tech advisors on this forum (tweaking the lengths of the throttle open/throttle close cables at the handlebar). The thinking was if the closing cable was slightly shortened (after slightly lengthening the opening cable), I'd be able to apply light force which would cause the idle to drop when at a stop. The throttle return springs are quite light on this bike. Currently, when the bike begans idling at 1500+rpm, I can lightly pull on the throttle linkage with my right hand, and the idle immediately drops to the desired speed. As soon as I release it, the idle speed goes back up to 1500-1600rpm. The cable adjustment idea made sense to me, unfortunately tweaking the cable length didn't appear to work. (Note - at the time the cable adjustment was suggested, the hanging throttle could be temporarily cured with a shot of WD40 on the throttle linkage springs)

I'll be doing a spring tuneup (plugs, TB balancing, TPS reset) which may help somewhat, but it appears to be more of a mechanical issue vs a tuning issue. Doing these things last year, plus canisterectomy, got rid of all the popping on overrun, but not the higher idle that takes place when the temps are on the cool side.

The drawings in the Teo Lamer parts manuals provide an illustration of the throttle bodies, but don't show (a) where the throttle cables attach, or (b) the linkage between the stepper motor and the TBs. And right now, it's just too cold in the garage to start removing the fuel tank to get a good look at the throttle linkage and cable attachment points.

Thanks for any thoughts on this matter.

Bob

 

[john zibell]

Check the adjustment of you throttle cables. It sounds like there is absolutely no slack in the opening cable. There shouldn't be much slack in the opening throttle cable, but there should be some. Also be sure the closing cable has just about no slack to ensure closing the TBs mechanically. If the cables are correct and you still have the high idle, some have had success by placing a restriction in air supply line for the stepper. Then since it is a US bike, there is always the cannisterectomy.

 

[draidt]

The stepper motor does not physically interact with the throttle bodies but works by injecting more or less filtered air upstream of the throttle plates depending on various inputs to the ECU

Click on the picture to enlarge

This is from the 8V training manual, but the 2V system is the same.

 

[ohiorider]

Thanks, John and Dan. First warm (and rainy) day, I've got a few simple tests and adjustments to perform.

Bob

 

[ohiorider]

Check the adjustment of you throttle cables. It sounds like there is absolutely no slack in the opening cable. There shouldn't be much slack in the opening throttle cable, but there should be some. Also be sure the closing cable has just about no slack to ensure closing the TBs mechanically. If the cables are correct and you still have the high idle, some have had success by placing a restriction in air supply line for the stepper. Then since it is a US bike, there is always the cannisterectomy.

John, I will do this again. I may not have been aggressive enough on taking the slack out of the throttle return cable.

Bob

 

[ohiorider]

The stepper motor does not physically interact with the throttle bodies but works by injecting more or less filtered air upstream of the throttle plates depending on various inputs to the ECU

Click on the picture to enlarge

This is from the 8V training manual, but the 2V system is the same.

Dan, this explanation is very helpful.

Bob

 

[ohiorider]

Check the adjustment of you throttle cables. It sounds like there is absolutely no slack in the opening cable. There shouldn't be much slack in the opening throttle cable, but there should be some. Also be sure the closing cable has just about no slack to ensure closing the TBs mechanically. If the cables are correct and you still have the high idle, some have had success by placing a restriction in air supply line for the stepper. Then since it is a US bike, there is always the cannisterectomy.

John, I will do this again. I may not have been aggressive enough on taking the slack out of the throttle return cable.

Bob

John, I took another pass at loosening the open throttle cable, and it has plenty of slack when I apply finger pressure at the left throttle body (probably a bit too much now). I then adjusted the throttle return cable length as tightly as possible at the handlebar control (actually ran the adjuster off the threads and replaced it approx 5 turns. Still no good. Once warmed up, she's right back at 1500-1600rpm. But I can still either pull the right side throttle linkage, or push on the left side throttle linkage and cause the idle to drop to 1100.

Here's my thought. I'm now certain you're correct about the return cable needing adjusted, but it appears I'm going to have to make the adjustment where the return cable attaches to the throttle body. There's an adjuster nut visible there, but I cannot access it easily. Solution .... pull tank and airbox to get to the adjuster, and while in there, replace the inner spark plugs. That will make it worthwhile.

Regards,

Bob

 

[GuzziMoto]

It sounds like you are going down the wrong road with this to me.
The closing cable is not there to close the throttle under normal circumstance. With the closing cable disconnected the throttle should still close completely. The closing cable is like a back up cable in case the throttle does not close on its own in emergency situations. It is the springs that close the throttle under normal circumstances.
However, if the closing cable does not have enough slack it can cause the throttle to not close or not close completely.
If you disconnect the throttle does the idle still hang? If so I suspect you have a set up problem.

 

[john zibell]

Guzzimoto may have a good point here. What put me on the closing cable road was the fact that you could get the correct idle by pressing or pulling on the throttle body plate linkage. Closely inspect this linkage. It should allow for the throttle body to hit the stop screw (don't touch that, it is the sacred screw). Inspect to see that nothing is interfering with the linkage. Also see if you can get some dry lubricant Into the pivots of the linkage. Also make sure the linkages are alined correctly and not binding.

 

[ohiorider]

Guzzimoto may have a good point here. What put me on the closing cable road was the fact that you could get the correct idle by pressing or pulling on the throttle body plate linkage. Closely inspect this linkage. It should allow for the throttle body to hit the stop screw (don't touch that, it is the sacred screw). Inspect to see that nothing is interfering with the linkage. Also see if you can get some dry lubricant Into the pivots of the linkage. Also make sure the linkages are alined correctly and not binding.

Guzzimoto is quite possibly correct. However, before I do a pre-riding season valve adjustment, TB balance and TPS reset, I do want to follow through on getting the return cable adjusted, since my return springs feel slightly weak ... which I think is a distinct possibility based on how very light the pull is on the throttle. This costs me nothing but some time. If that doesn't cure the issue, surely doing the TB/TPS will, and if not, blocking off the stepper will take care of it. Since I'll be under the tank, I'm ordering a new air cleaner and two inner plugs today. (guess I should also purchase a small valve to install in line between air box and stepper motor.)

BTW - I don't intend to touch the 'sacred screw', but if one were to raise or lower idle with it, what are the effects? I'm imagining it would cause the idle to hunt, as the ECU attempted to set the idle to the rpm set in memory.

Thanks again, everyone, for staying with me on this. I'll drop a note to let you know how this works out.

Bob

 

[john zibell]

If you move the screw, it will throw off the entire injection mapping. The map is based on throttle position. If you move the screw and reset the TPS, the ECU will get incorrect information and mess up the running.

 

[motobob]

Sounds to me like you may have some slight interference problems some where preventing full closure of the throttle plates. Quick story just to illustrate: Summer of 2010 I helped a buddy redo his tranny in his r1150rt beemer, rebuilt all back together everything where it should be and no problems. He rode the bike all the rest of the riding season put it away for winter started riding again in the spring and in July we took a week trip, and half way through the trip it started running terribly at low speed but on the highway all seemed good. Tried many things but finally decided to bee line for home hoping to get as close as possible in case the bike went south. So anyway one of the last nights away, after a couple of rum and cokes he says to hell with it lets strip the body work off and see if we can figure this out, well guess what it was, a hose clamp had some how worked its way into dragging on the cable quadrant on the throttle body just enough so that it held the right side open at low speed, of course causing severe erratic behavior at low speed.
Bob

 

[ohiorider]

My thoughts, too. A few pieces arrived in the mail that require removing the fuel tank (new air filter, inner plugs, Haven starter wiring mod), so first warmer day in the garage, tank comes off and I find out whats going on with the throttle cables. Amazing how such a small thing can be such a major irritant. (I know the tank can stay put for most of the above parts aside from the air cleaner, but once off, I find it so much easier to work on the bike ... aside from disconnecting the fuel line!)

Bob

 

[coco]

Hi,
I have the same problems, would like to know how was solved?
Thanks in advance

 

[kiwi dave]

Hi,
I have the same problems, would like to know how was solved?
Thanks in advance

Easiest way to determine if the stepper motor is the culprit is to squeeze the hose between the air box and the stepper motor with a pair of pliers. If the idle changes, then yes the the stepper motor is contributing to the high idle.

On my 1200 Sports bikes, I have installed a pneumatic switch to kill the affect of the stepper motor for normal operation. The stepper motor is valuable only when the motor is cold, otherwise who needs it?

If you have a Breva 1100, a later map may be beneficial.

 

[coco]

Hi,

Thank you for you reply Dave, I am sitting down south Chile, with very less possibiliitys of technologie, is possible to eliminate in a easy way the stepper?

I am copying an extract of Bob's exposure, and is exactly the same issue on my bike!!! :

...."The throttle return springs are quite light on this bike. Currently, when the bike begans idling at 1500+rpm, I can lightly pull on the throttle linkage with my right hand, and the idle immediately drops to the desired speed. As soon as I release it, the idle speed goes back up to 1600-1900rpm."

By the way I am riding a 1200 Sport 2009

Thanks in advance

 

[GuzziMoto]

On a fuel injected bike with butterfly throttles, like a FI Guzzi, you do not need much spring to close the throttles. That is, in part, because the butterfly throttle plates have air pressure pushing equally on bother sides of the throttle plate, the right half and the left half (Guzzi butterflies pivot vertically). Pressure on one side is pushing the throttle open, but there is equal pressure on the other side pushing the throttle plate closed. It is basically balanced, so all the spring needs to do is add a little force to close the throttle.
If the closing cable is adjusted too tight it can cause a bind, where the two cables are working against each other, and that can cause the spring to be too weak to properly close the throttle. The fix, in that case, is to add more slack to the closing cable. Tightening the closing cable would actually make it worse.

As mentioned by Kiwi Dave, I have added a valve in my stepper motor system that allows me to turn the stepper motor off. But, as Dave mentioned, an easy test to see if the stepper motor is part of the problem is to use a clamp or a pair of pliers to close off the line between the air box and the stepper motor and see if the issue stops. If it doesn't make a difference the stepper motor is not part of the problem.

 

[coco]

On a fuel injected bike with butterfly throttles, like a FI Guzzi, you do not need much spring to close the throttles. That is, in part, because the butterfly throttle plates have air pressure pushing equally on bother sides of the throttle plate, the right half and the left half (Guzzi butterflies pivot vertically). Pressure on one side is pushing the throttle open, but there is equal pressure on the other side pushing the throttle plate closed. It is basically balanced, so all the spring needs to do is add a little force to close the throttle.
If the closing cable is adjusted too tight it can cause a bind, where the two cables are working against each other, and that can cause the spring to be too weak to properly close the throttle. The fix, in that case, is to add more slack to the closing cable. Tightening the closing cable would actually make it worse.

As mentioned by Kiwi Dave, I have added a valve in my stepper motor system that allows me to turn the stepper motor off. But, as Dave mentioned, an easy test to see if the stepper motor is part of the problem is to use a clamp or a pair of pliers to close off the line between the air box and the stepper motor and see if the issue stops. If it doesn't make a difference the stepper motor is not part of the problem.

Thanks John,
For instance I will check with the pliers, just to know where can I get and what kind of a valve do I need?
Coco

 

[Bisbonian]

Thanks John,
For instance I will check with the pliers, just to know where can I get and what kind of a valve do I need?
Coco

This is what I used: https://www.amazon.com/gp/product/B00230ECOK/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

I think there are a few different ways of doing this. I just ran the hose from the bottom of the air box to the valve, and then from the valve to the stepper. Open the valve on a cold morning to get some fast idle and then when I start getting some exhaust popping I shut the valve off. I've been running it this way since 2013.

I've seen at least one person who plumbed one end of the valve to the stepper and then put a small filter on the other end of the valve. That might make it a bit easier to install but it also means more parts to buy. Of course they would have capped off the nipple on the bottom of the airbox as well.

 

[Brian UK]

I control my valve with a temperature switch fixed to the cylinder head, soon as it gets to 70 degrees Celsius it switches the air off.

If you find that opening the throttle a tiny bit drops the speed, then almost certainly the stepper motor is causing it.