Vespa Largeframe fuel tank for fuel pump

Modified Vespa Largeframe tank with tank-in-tank construction for operation with a fuel pump, suitable for all Vespa Largeframe models.
The basis for this construction is a Vespa largeframe tank with a lever closure, into which we implement a second intermediate tank with a capacity of approximately 0.8 liters, positioned at the highest possible level:
The fuel pump required for this design constantly pumps the fuel from the main tank into the small tank, which has an overflow at its highest point that leads back to the main tank - the fuel tap draws the fuel from the always completely full small auxiliary tank.
In this way, the carburetor is always filled from the highest level, regardless of the total amount of fuel in the tank. The atmospheric pressure remains constant until the last half liter of fuel is reached, and due to the higher intermediate tank, it is even higher than with a completely full original fuel tank – a huge advantage compared to dual-circuit fuel pump installations, which naturally have problems with pressure differences that depend on engine speed and fuel level, and therefore do not guarantee a truly constant fuel supply.
The Scooter & Service Largeframe Tank with tank-in-tank construction can be operated with both electric fuel pumps and a vacuum pump - long nuts with M6 threads are attached to the underside of the tank for attaching the pump used.
The existing fuel tap lever must be shortened accordingly due to the changed position of the fuel tap - the tank fits with most common seats.