Originally Posted by
EuropeanAM
Fuel System Connections should be available in the Factory Service Manual.
Section 3-C covers most of what you'll need to know.
The two fittings circled in your thumbnail picture are:
There were several versions of the VST, it "appears" you have the latest one. The INNER (closest to the block) fitting should be the VENT hose, which loops to a hole in the adapter plate (so that fuel would dump into the lower cowling if the VST flooded).
The OUTER fitting (faces AFT or BACK) is the fuel inlet, coming from the mechanical fuel pump.