Throttle Body Balancing

[Huzo]

I need to have it explained to me what the idle stepper readouts are conveying.
This is the current status.


The bike is performing nicely, so I don’t suspect any gremlins are present, but I do note that stone cold startups require a bit longer than ideal crank time.
Can be up to 5 seconds, but from there on it’s just perfect. Could my stepper be “parked” in a condition that is allowing too much air (producing a leaner than optimal condition) and is this reflected in the display ?
IF this was the case, can I intervene safely and have the stepper park at a more closed setting ?
I have no clue on this topic, so any answers I (hopefully) get, will need to be pretty basic or I’ll get lost for sure.
Thanks in anticipation.
Huzo.

[tris]

There's lots written about sticky ICVs so it could be that, and it's worth noting that Ducati (which is where this was sourced from) went away to a different design

Also the perceived wisdom ist that the metal bodied (older) are not as good as thecplastic ones

But as a trial you can pinch off the inlet to the ICV and see if that helps before fitting a valve in line.

I found a stepper motor controller board on line and coupled that to a 5v  USB power supply and the appropriate Ducati connector allowed me to stroke the valve over its full range.

That's how I worked out that it leaked

HTH

[Huzo]

I’m not suggesting that there’s any malfunction present, but I’d like to know what the numbers mean.
Is there anyone out there with a 2 VPC Norge like mine, that can show or tell me what numbers they get ?

[Seweryn]

Thanks for the replies, very interesting.

I am trying to resolve the abrupt running off/on throttle between 4.7 (throttle closed) and about 5 degrees (throttle very little open) when driving in traffic and low rpm, engine braking, etc.

I have a modified fuel map installed, but that only helped a bit and I am trying to eliminate all other issues.  I may try with blocking the inlet to the stepper and see if that helps.  I think the issue is with too lean mixture to one or both cylinders between 4.6 and 5 deg. and (in my opinion) it is unlikely anything to do with the fuel map.

BTW, do you know the diameter of the rubber hose inlet of the step motor?  I am thinking about running a rubber hose through a mechanical valve between the air filter housing and the stepper hose / inlet.

[tris]

BTW, do you know the diameter of the rubber hose inlet of the step motor?  I am thinking about running a rubber hose through a mechanical valve between the air filter housing and the stepper hose / inlet.

Sorry it's 4 years since I played with a B1100  but I think it was 8mm

If anyone is interested as best I can tell from my 2019 Ebay history, the bits for the circuit to stroke the valve is
Stepper motor controller Ebay:- 294651017040
Ducati connector Ebay:- 192918850805
USB power:- chop the tail off a wired mouse 

[Huzo]

Here’s how my new mercury manometer went. https://youtube.com/shorts/um5MnfzZXUg?si=eDkFGg0qmC53yrws
I went ahead and did the rest of the procedure as required.
Suffice to say that this open loop one works better than the previous closed loop effort.

[Seweryn]

I ran a test at the weekend by installing a valve on the inlet hose to the stepper.  The bike ran a lot worse and was difficult to control on cold engine, so I abandoned the idea.

I am not sure what it is when the bike runs not great (it sometimes runs just as you would expect).  I am trying to trace the issue, but running out of ideas.  The engine does not pick up smoothly from the closed throttle position to a very little open position (5 - 6 degrees).  When I slowly open the throttle from idle, there is no reaction / hesitation until about 5+ degrees of opening angle and then the engine surges a little.  On the road there is a clutch action required often at roundabouts and junctions to compansate for that.

I connected GuzziDiag yesterday to see if the TPS reads the minor changes at low opening angles and it seems to be OK.  There can't be many other issues (a bit of play on the throttle shaft?), but I understand the sensitivity of the throttle control system.

[Huzo]

I ran a test at the weekend by installing a valve on the inlet hose to the stepper.  The bike ran a lot worse and was difficult to control on cold engine, so I abandoned the idea.

I am not sure what it is when the bike runs not great (it sometimes runs just as you would expect).  I am trying to trace the issue, but running out of ideas.  The engine does not pick up smoothly from the closed throttle position to a very little open position (5 - 6 degrees).  When I slowly open the throttle from idle, there is no reaction / hesitation until about 5+ degrees of opening angle and then the engine surges a little.  On the road there is a clutch action required often at roundabouts and junctions to compansate for that.

I connected GuzziDiag yesterday to see if the TPS reads the minor changes at low opening angles and it seems to be OK.  There can't be many other issues (a bit of play on the throttle shaft?), but I understand the sensitivity of the throttle control system.

Can you take a shot of this page on Guzzidiag ?

<br /
I’ll be interested to see the comparison.

[Seweryn]

Can you take a shot of this page on Guzzidiag ?

I’ll be interested to see the comparison.

Yes, I am sure I can do later this evening.  The engine is off I see, but warmed up.  My CO Trim is at 0, do you need that changed to 10?

[Huzo]

Yes, I am sure I can do later this evening.  The engine is off I see, but warmed up.  My CO Trim is at 0, do you need that changed to 10?

I hadn’t noticed on the status bar, but it says clutch pulled and that’s not the case.
Can’t explain that one.
As for the CO trim number, I’m told that each increment adds one microsecond (or something similar), to the injector pulse width, I don’t know if that helps the cold start mixture or not, but there it is anyway…

[Seweryn]

Here are the screenshots:

[Huzo]

Ok .
I notice there are a few differences in some of the details. Can these be explained ?
Mine.

Yours

[Seweryn]

Is your engine 2 valve?

[Huzo]

Is your engine 2 valve?

Yes, ‘07 2 VPC

[Seweryn]

Yes, ‘07 2 VPC

That may explain the differences.

BTW, I am using a custom fuel map.

[Huzo]

That may explain the differences.

BTW, I am using a custom fuel map.

Yes ok, point taken on the 2VPC / 4 VPC thing.
My map is also non standard, Beetle.

[Seweryn]

Do you know where to source a bushing and seal rebuild kit for the throttle bodies?  I don't believe I can improve things further unless I eliminate the play in the throttle shafts.

[Huzo]

The bushes would probably be something you could make, but the wear on the shafts would be a problem.
They’d need to be precision ground.

[Seweryn]

I have just inspected the valvetrain and found that the left cylinder inlet valves were both loose - I guess they were at 0.3 - 0.4 mm.  The rest of them were more / less OK.  I then ran the vacuum test and found that I needed to correct the high rpm ballance by almost third of the turn of the screw (clockwise) for the vacuum balance.  Does that seem right?  It means that I now need to increase the opening angle of the right cylinder throttle by about 0.5 degree (roughly measured with Guzzi Diag).  Then to compensate for the idle I will need to open the left cylinder bypass screw (currently both are closed).  It all means there will be more air getting into the engine at idle.  I started the balancing work yesterday but didn't finish yet as the correction values were surprisingly high to make it in balance, so I had to sleep with all this in my head.
 
Your valuable comments would be appreciated.

[guzzisteve]

Sounds correct, adjust bypass on one to make columns level at idle.
Huzo may be sleeping being in Australia.

[Huzo]

Again Seweryn, it’s sounding more complex than it is.
Close the bleeds.
Run up to 3,000 rpm.
Adjust the CORRECT screw to match the manifold depressions.
Close the throttle.
Open the appropriate idle bleed to get idle depressions balanced.
Set the TPS with Guzzidiag.
Open and snap shut the throttle.
Re check TPS.

There won’t be “more air at idle” under normal circumstances, because the stepper will move to manipulate the air/fuel ratio to achieve 1150 rpm.

[Huzo]

  I then ran the vacuum test and found that I needed to correct the high rpm ballance by almost third of the turn of the screw (clockwise) for the vacuum balance.  Does that seem right?  It means that I now need to increase the opening angle of the right cylinder throttle by about 0.5 degree (roughly measured with Guzzi Diag).

This part of your statement is what I find a bit awkward.
When you move the balance screw, you are moving the right throttle, to balance it with the left.
It is the left plate that has the throttle stop (do not touch this one…)
Once you have tweaked the adjustment screw to balance the throttles, you have to re set the TPS with Guzzidiag.
This is to “tell” the brain in the bike what 4.6-4.7 degrees looks like.The bike does not know what 4.6 degrees is, it just knows that you have nominated it’s closed position as 4.6 degrees. It just says..”oh ok then, I’ll take my readings from that point…”
Remember your TPS is on the RIGHT TB, the throttle stop is on the left.
If you follow the procedure, you do not have to reason it out too much.

[Seweryn]

Thanks Huzo,

I understand all the procedures and had set the throttle balance before.  I was just surprised that the valve clearance made a noticeable difference to the vacuum - finally about 1/4 turn was the correction I had to make.

[Huzo]

Thanks Huzo,

I understand all the procedures and had set the throttle balance before.  I was just surprised that the valve clearance made a noticeable difference to the vacuum - finally about 1/4 turn was the correction I had to make.

Yes S.
Roper is all over that  one. I guess you could make the case that any alteration in valve clearances makes a discernible change in gas volume and therefore cylinder pressure.
That’s gunna’ alter your depressions on the manometer and be recognised as an imbalance.
Touche’ Sir…

[Seweryn]

Hi All,

Would it be possible to identify if my engine was converted to rollers from these photographs?

[paulbricey]

Probably as you have the revised earth tang & second pic looks rollerish to me (although bad camera angle). Here's what you are looking for

[guzzisteve]

The bottom pic you can see the roller on bottom of fork. you got rollers.

[John Warner]

9. Use the 'Re-set parameters' function in actors.

As I understand it, resetting the Autolearning Parameters is only necessary after a remap.
After a TB Balance/Sync, all that needs resetting is the TPS, due to the TPS sensor being on the R/H TB.
If the Sensor were on the L/H TB, you wouldn't need to reset it.

[Huzo]

But Tris, the sacred screw never has and never will be, there to set the idle. The stepper is there to adjust the fuel/air mixture to set the idle to the target value of 1150 or so…
The TB will never be correct until you can adjust the sacred screw to match the flow rate set ex factory.
I have brought a set back that were monumentally molested, by attaching a known good one to an air reservoir and timing a dump using a manometer between two arbitrary limits.
I recorded a dump time of 20 seconds on a control unit, then adjusted my rooted one to reflect the new value.
You do not need to know what the flow rate is in litres/minute, just that it is the same as the factory one.This is the principle. https://youtube.com/shorts/NGHMAry4iks?si=tAJjtAJwDdP44oFZ

[John Warner]

Do you know where to source a bushing and seal rebuild kit for the throttle bodies?  I don't believe I can improve things further unless I eliminate the play in the throttle shafts.

There is no such thing I'm afraid.
I have read/heard of a couple of owners doing a re-bush (or at least getting it done by someone), but I've yet to find out the details.
To be correct, it's not a re-bush, as the Throttle Plate Shafts just turn in the Throttle Bodies, there are no Bushes.
The fix is to machine out the TBs and fit Bushes.
I very much doubt the Shafts would wear, they'll be much harder than the soft Alloy of the TBs.

Any appreciable wear will let air into the Intakes, making TB Balance a lot more difficult to get consistent results from.