If you have an air compressor, and you know what # spring you have installed in your race gate, you can hook up a line from your air compressor to the bottom port of the race gate and slowly apply pressure to the gate, starting at zero.
If for exaple you have a 14# spring in the racegate, when your pressure gets close to 14psi, the valve should start to open up. It should be fully opened at 14-16psi. With different tollerances and conditions of the spring, the fully open pressure could vary by a couple of psi.
If you hear or feel air leaking from the diaphram, (outter perimeter of the gate around the diaphram seal) there's a good chance that it is torn and needs to be replaced. Go easy on the pressure when checking it, no sense blowing the gate apart. :redface: The valve should fully close when the pressure is turned back to zero. If it hangs open, I would suspect carbon buildup on the valve guide and or valve seat. That would require a further tear down inspection.
This is how I would check one.
Patrick