High Idle Speed - SOLVED AT LAST

What about the TPS Roy?

GD can graphically show signals and the TPS is one of them.

It might be worth setting GD running (I think you can do it with the engine running or not) to track the TPS.

Then steadily/slowly open/close the throttle and see if there are any jumps in the trace. Also with the throttle closed try some judicious light taps with your toffee hammer and again see if the trace jumps about

My thoughts being if the ECU thought the throttle had closed somewhat due to a change in the TPS value, then it might open the stepper to compensate

Feel free to disregard if this is gibberish!

Not sure stepper would respond to TPS trace - Service manual says ECU changes stepper & ignition timing to correct revs to target revs (& target revs is mainly adjusted by measured engine temperature).....wouldn't it be more likely that stepper is jumping because the engine temperature measurement is jumping around (assuming stepper is OK itself) ?

Don / Paul,
                 Thanks for weighing in.
I'm sure the stepper is giving me a clue, the sudden drop from ~60 to zero accompanied by the increase in revs. Blocking off the stepper inlet hose will bring it back down about 500 revs but it can still be doing 2000, I can feel it sucking on my finger.
I now think the sudden drop was the result of the revs shooting up, not the cause.

The throttle opening remains the same. I believe that's the TPS Voltage expressed as °

I have just one bypass screw open about 1/2 to 3/4 turn.
I thought it might be air getting into the crossover hose where the canisters were but that's well plugged off.
Next step will be to pull off the throttle bodies in case there's something weird going on there, it's pretty hard to check it properly on the bike.

With Mark's pdf (bottom of page 2) I now have a good set of instructions

I'm sure it's something really stupid, I have missed so I welcome any input.

A general question:
I think the stepper valve feeds into the air bleed screw, is that correct or is the stepper a separate port?

I'm not sure what the internal plumbing of the throttle bodies are but the air bleeds are underneath (see pic) and the stepper air comes in through the rubber pipes that connect at the top (see pic) ...but they might meet inside and enter inlet at same point (can't remember how many holes in body near the butterfly !)

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Found this - looks like they are separate !

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Paul,
Is there anything holding the throttle bodies in place or are they just supported by the intake rubbers?
Obviously the throttle cables, what about the injectors?

I'm sure Pete has told us but I was staring out the window in that class.

Actually that's an 1100 ...

Just the clamps on the inlet bodies & the airbox connection (after taking throttle cable off)....it's a squeeze to remove them past rubber but no other bolts. Injectors are on the inlet tract so don't have to come off - see below picture after TBs off

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Thanks Paul, It looks a lot easier than I thought, I will try to fit it in this evening.

One thing I didn't mention I have more than the usual cable slack, I loosened it off when the problem first arose but I don't see how that could cause anything, the throttle reading doesn't move.

I pulled the throttle bodies off this evening, I just pulled it out the RH side without lifting the tank, I don't think it will go back as easy.

I didn't find anything unexpected but there is about 0.5 mm of end float in the butterfly shaft, does that seem excessive?

I took some pictures looking into the throttle with a light on the other side of the butterfly to show the effect of pushing the shaft first one way then the other.

There is also about 1mm end float in the linkage tying the butterfly together although being spring loaded its kind of under tension, so it should be consistent, might possibly stick under vacuum but that should show as a difference in the throttle opening on GuzziDiag.

I inspected the grub screw, no sign of tampering. The link rod also has the yellow paint intact.
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RH throttle body was the dirty one, fairly clean now since I sprayed in there with carb cleaner
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LH looks pretty grubby, I didn't spray in that one because from the other side it seemed fairly clean.
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I held a lamp in the throttle and pushed the shaft first one way and then the other
LH pushed one way
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Then the other
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RH pushed one way
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Then the other
I think the light shining through the gap makes it look worse than it really is.
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Showing end float, I thought this seemed a lot, there's no reason it couldn't be 1/10th of that.
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I think I will attempt to shim out some of the end float in the shafts but I don't think that will make any difference to the amount of air that gets through. I can only see one way of changing that.

XX

Mine has similar 'float' and 'gaps' and runs fine....sometimes just removing, cleaning & refitting (& re-balancing etc solves the high idle issue.

Thanks Paul
PM Sent

paulbrice wrote:

Mine has similar 'float' and 'gaps' and runs fine....sometimes just removing, cleaning & refitting (& re-balancing etc solves the high idle issue.

(Cough!)

It turns out that it was the Bell Crank. If you move that too far it opens the RH throttle adding too much air. To get balance at idle you then add even more air via the air bleed.

I closed both air bleeds and started the bike, still idling too fast so I backed off on the crank until the revs came down then went for a ride. It seemed to be running nicer than it ever had before.
Just out of curiosity I hung the manometer on, it was within 6" (oil filled "U" tube manometer)

Tip: if you use plastic hose to make a manometer be sure to make the final connection to the throttle bodies with something like rubber that will take the heat otherwise the plastic will become soft and drop off or leak air making the levels unstable.

If I might suggest a something.

With both air bleeds closed and the engine at idle the stepper motor should be able to add enough air to maintain idle speed (the stepper valve ports are larger than the air bleed screws)
If the engine is idling too fast try backing off on the Bell Crank CCW see if that lets it slow down, it could be that the crank is wound in so far the RH screw is open letting too much air in.
if you hook your finger around the back of the crank you will feel the tip of the screw, I find mine projects through the metal by only 2 or 3 mm, any more and the idle starts to climb suggesting that the butterfly is too far open.
I took some measurements with a dial gauge and found for every complete turn on the Bell Crank screw (very fine thread) the Right hand butterfly opened (turned by) 0.015",


In a normal link lever system both levers normally start out at the same angle and follow each other.
Changing the length of the link in a link lever system effects the linearity because it changes the relationship of the two levers skewing the angle as they pass through mid range of travel. I expect this adjustment is used on the flow bench to compensate for any differences in flow over throttle angle.

It's hard to visualize the difference between changing the angle of the bell crank and changing the length of the link, perhaps its one and the same.

Great you're sorted & nice detective work Roy .

Is the bell crank screw the "sacred" screw? Or the adjustment screw?

Adjustment.

The idle stop on Left throttle is sacred and I assume the Link length is also sacred although I don't see why as it's coupled to the Bell Crank.

I think the reason they don't want you touching the idle stop is because the stepper needs to have control over this fine air flow so it can make the bike idle properly.
It also means all bodies are set the same I assume the factory just slap them on and don't need to fine tune anything.

On my bike the bell crank was so far out it overwhelmed the left butterfly with the right one too far open.
I was partly to blame for that although it was fast when I first bought it, I screwed it up worse.
Never mind, I saw the light.

After riding the bike for several days I can say it's never run better
I am running the stock map I think see below
I'll hold off on one of Marks maps until I can afford an after market exhaust.
And a decent laptop.

This is what I see when I log in with GuzziDiag

IAW5AMPF16
Z229GRS1103
IAW5AMHW610
NX9T002240
2011.20.07

Does it have an upgraded map?
Thanks
Roy

Mark will tell you what that all means , but its definitely not a beetle map. if you think it goes good now .............. Just you wait Kiwi boy , Just you wait
PS: glad you have it all sorted

Not loaded by GuzziDiag either. Either Rexxer, or some other 3rd party.

NX9T002240 - likely the software loader identifier.
2011.20.07 - the date it was flashed.

One Question from my poor understanding:
How will affect this the synchronisation of the System above idle? If the right hand butterfly has to be more opened to achieve a good synchronisation measured by dp??
So i have to choose between normal idle revs or good synchronsation at 4000 rev?