What's that on the cowl under the horn? Air pump to pressurize the fuel tank, or an accessory oil feed?
Manual fuel pump on the side?
There are two different pumps. The top one has only one line and the bottom has two.
Top would be an air pump to pressurize the gas tank. Lower is usually an oil transfer pump to move oil from a storage tank to the crankcase, often seen on race cars, rarely on speedsters.
Maybe in a Model T, this guy used the lower pump to transfer water to keep the radiator full!