CB1100 Idle speed instability problem

[Speed_imp]

Yesterday I removed my old IACV looking for coil wiring, magnet or mechanical fault. The housing and the spool of the valve do not show evidence of wear nor any kind of marks




I tried heating up the valve (sorry but I don't have the heat gun at home) to check coil resistance when hot. Resistance went up to over 120 Ohm, both coils the same. At the moment of the measure the valve was fuc..ng hot.



The spool of the valve its threaded or bolted on to the rotating axle. When the axle rotates the spool expands or retracts by action of the thread. It is not "one piece", the thread part is mounted over a spring and if you force it both parts can slip in reference to the other, still difficult to say there might be an issue




I exploded the valve looking inside for metallic build ups and to see the architecture of it



The coil is clean inside with no metallic build ups



In order to chech the condition of the magnets in the rotor and the magnetic field intensity I did an induction test which I will show you later

Old IACV supplier reference



New supplier reference


After all the checks I have not found an evidence of failure. Always thought that one of the magnets in the rotor could be weaker than the others thus failing in one of the steps and tyhen not being able to keep on turning in the same direction again. I made and induction test where I could check the whole set of magnetic field intensity and coil wiring

https://youtu.be/WcO3KK_2LMA

As I said I have not found a fault anywhere, it makes me think of a mechanic failure probably in the spool of the valve, I has two separate bodies joined by a spring and you can turn one in respect with the other if you slightly force it, where the system could loose the real position of the valve and giving a mistaken fuel mixture after that. I want to emphasize that my issue was LOW IDLE, never had high idle issues