I guess I have to try to defend my honour.
Can we agree that the T.E.V. diaphragm has manifold pressure on one side and atmospheric pressure on the other side. If this is acknowledged, the diaphragm is pulled/sucked to the right when the throttle butterfly is closed. Fuel from the float chamber then flows into the other side of the chamber, about a teaspoon full? This fuel doesn't go anywhere it just sits there, no flow in other words. Then, when the throttle butterfly is opened, manifold pressure rises, to what degree necessary I don't know but Mikuni engineers figured it all out with the spring tension and diaphragm diameter. Anyway, at this point, the T.E.V. spring does its thing and pushes the diaphragm over, therefore supplying a "teaspoonful" of fuel to the engine to help prevent it from going lean.
My reasoning is that the passageway from the carb throat to the spring side of the T.E.V. is drilled on the engine side of the carb butterfly.
I hope I am not all flipped up but for the life of me I can't come up with anything else.
There you go guys. Shoot me down! I hope at this point that I am not wrong but when Dave Batman and Versy get through with me I may wish I had kept my mouth shut.