I think a rubber tire tube will dissolve with gas, possibly contaminating the carb. Just a heads up. You'll want to use something fuel safe for this IMO.
Looks like manifold vacuum on one side and air on the other side. Valve closes air to low speed jet, richer mixture does NOT ignite.
Also if someone wold have a defective ACO diaphragm then to investigate if JBM Industries would make one for a VTX.
I am using a JBM Industries slide valve diaphragm.
Or get in touch with me...
OEM ACO hose plugged, quiet at 50 > 35 MPH decel, pops at 80>60 MPH decel, pops at 20 MPH decel in 1st gear(this was the loudest).
My first half dozen 50 MPH decels were quiet, wind noise may have masked some pops.
At 3500 feet or higher my X is a pop-corn popper. Constrained some by baffling, not explosions nor gunshots..