Air cut valve

I am trying to understand how this valve works on the FCR MX 41 of my husaberg 650. I have noticed that a spring presses the pin diaphragm which in turn opens a bypass which adds air into the pilot circuit, making it lean. A duct carries the vacuum signal on the diaphragm which overcomes the thrust of the spring and retracts, closing the bypass which adds air to the pilot circuit. So it makes me think that the engine always works with added air from the passage opened by the diaphragm, and that when you decelerate the excessive vacuum closes this bypass. Does "air cut valve" mean that there is an air bypass always active except when the vacuum "closes it"?

I am saying that the air cut valve does not add fuel in deceleration, but is constantly leaning the pilot circuit, except in deceleration when the vacuum activates the cut.

I m not at home, but this is from spare parts husaberg 650 2007

This is my carb.
In the center of the photo, in the hole of the brass piece c is a one-way valve which is opened by the diaphragm pin. I repeat it is always open except when a strong vacuum retracts the diaphragm. Taffy would you like an additional hole in the pilot circuit? A second PAJ? I don't think so ... that's why I cut the diaphragm pin to keep the valve always closed (as would be an FCR without air cut valve)