CB1100 Idle speed instability problem

[Speed_imp]

My old IACV phisical condition:

https://youtu.be/0HCgrUdMVIQ

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Speed ​​,
I want to test IACV by connecting it to the power supply.
I want to see if it turns with the same power to the right as to the left.
I don't want to damage the IACV by wrong connection to 12v power supply.
There are 4 connectors.

According to SM one coil - two inside connectors
second coil - to outside connectors


Question:
If I connect the IACV in the wrong (reverse) polarity can I damage the IACV coil ?

No, actually each coil is receiving first 12 volts from one side and then from the other side alternatively as shown in the shots I took, that is why measuring both ends you can see alternative pulses 12V and -12V

Sync, it runs on 12 v just like Speed mentioned, with a resistance of 105 ohms that means the current is 0,12 Amps or 1.5 wattts per step, not very strong.

There are 2 sets of coils inside and a multi pole permanent magnet on the rotor;



As the pulses are sent from the e.c.u. the motor "steps" with every pulse to it's next position;



You can apply some dc from your supply but the iacv will only move a small amount in one direction, energizing the other coil will move it some more, very un-interesting and disappointing to look at but it will show you the principle.

Normally the current in the two sets of coils is reversed as well but i think if you just take the 12v supply wires and pulse coil A then coil B etc. that will motivate the rotor in one direction ( video? ) and there is no danger in changing polarity in the coils,, they just move in the opposite direction.

In order to not damage the iacv use very short times to energize the coils, if the dc is applied for a long time they will overheat i think, it's very thin wire.

One possible explanation could be that the permanent magnets inside the iacv loose strength over time due to the heat which is a known phenomenon with magnets and would explain why it occurs in slow traffic with heat building up in the throttle body, just a guess and probably not the cause, it could be that the software change produces better pulses with full pulse with other than just a smaller peak as shown in Lord Popgun's nice video.

Thanks for your video, it answers a lot of questions i had previously but it still does not solve the mystery why it fails, although i found the marks inside the groove interesting, awesome of you to post this!

That's it Max, what a great graphical explanation! The way it moves to one or the other direction is inverting B and B' for example, in a similar way you change the direction of a triphasic induction motor. I think we are at this point very close to reveal what is the exact issue. I am also sorry it is getting too deep diving technical but I am very interested as it is happening in my own bike. I owe her the time spent and of course I am having so much fun actually!