This is my first post on the forums! I am "restoring" (mostly just doing overdo maintenance) my father's 1983 GPZ1100 (DFI). I am located in the Huntsville, AL area. Part of the maintenance needed is the replacement of the fuel lines. As I was replacing the fuel lines, I noticed that the vacuum hoses leading to the Clean Air System were cracked and needed to be replaced as well (just another thing to do
Going to be doing this on the ZRX this Winter, remove the clean air system.
Saves a bit of weight, and cleans up under the tank.
Has to come off to do a valve clearance check too, which I will be doing.
I've bought block off plates, but you can plug the stock ones, or run a hose between the two.
The air box connection will need to be plugged, as well as any other connections, such as the carbs in the ZRX's case.
The regulator-looking thing is just a vacuum-controlled valve. Air is allowed into the exhaust ports by default under most conditions, but when you decelerate that would lead to popping in the exhaust, so the air is shut off by that valve during deceleration. It is controlled by vacuum in the intake which is very high during decel. This works fine because the mixture is always lean during deceleration anyway, so you don't need the extra air in the exhaust at that time. (Same reason why you get popping on decel if you go to a free-flowing exhaust without adjusting the jetting.)
When the vacuum lines leak or the valve gets stuck open, you get big pops in the exhaust during decel. That is the main symptom when the clean air system fails open. As the others said, it doesn't affect performance much or at all since it's only affecting the gases after they have left the cylinder.
If it's not working, or you just want to be rid of it, you just have to remove everything and seal off the openings and vacuum lines.
I would agree with the first response to just replace the existing vacuum lines as they do go to the pressure regulator required for the fuel injection on your bike. You MAY be able to just reroute the vacuum lines from the intake boots to the pressure regulator to do away with the clean air system on the valve covers but I'm not sure if that would change the vacuum and therefore affect the pressure regulator ?