This kit updates the fuel valves on 750 Ambassador and 850 Eldorado fuel tanks to a later, next generation type of fuel valve that was used on later Guzzis. Think of it as upgrading from a 1960s valve design to a later 1970s valve design. One appreciated benefit of this update is that the newer valves are specifically left side and right side valves, which means that the "on/off/reserve" valve handle positions will be oriented the same on both sides of the fuel tank. And, the valve handle positions are more clearly labeled and easy to look down and see. Beyond that, many people consider the newer valves to be more resistant to damage caused by fuel additives.
This kit contains everything you need to update the petcocks on your Ambassador or Eldorado fuel tank. You get: 1 new left side petcock, 1 new right side petcock, 2 threaded aluminum adapters, 2 plastic gaskets to seal the petcocks to the adapters, and 2 fiber gaskets to seal the adapters to the fuel tank.
Note: you must remove the filter screens from the new petcocks prior to use. Ensure that the plastic tube that creates the reserve function is fully seated and secured in the correct hole. In order to ensure that you have adequate fuel filtering, you might inspect the fuel inlet screens (43934000) where your fuel lines attach to your carburetors, and refresh them if necessary.