CB1100 Idle speed instability problem

[Enzofour_imp]

Enzo since you have a bad iacv can you think of a reason that made it fail slowly?
And which screw was the most difficult to remove in the airbox?

As I wrote in another post, I bought the bike used in November 2020.
Due to lockdown covid I did very few 400 km approx. Twice it turned off due to a too low minimum, the last vote was turned off by the Honda dealer who found the problem, in fact the new IACV valve is given to me under warranty.
No screws were particularly difficult, the difficulty was getting the filter box out of the frame, due to the very little space.