By the way, a good bench synch will make the vacuum synch MUCH quicker and easier. If the bench synch is poor enough or no bench synch, many owners end up killing the battery just trying to start the bike.
Also, as with any synch... First warm up, then adjust the side air screws for best idle/rpm using 1,000 rpm as a base. Your bike should have the side air screws set initially about 1 1/2 turns out before start up. Fine tune them.
Then, do your vacuum synch.
I made a detailed post on bench synching the VM carbs at another thread, but I didn't save it. If interested in it, do a search. The thread is in the technical section, authored by "Hoomgar", title is something like: "GS1K re-jet, poor fuel mileage, attn Keith Krause".
Also, as with any synch... First warm up, then adjust the side air screws for best idle/rpm using 1,000 rpm as a base. Your bike should have the side air screws set initially about 1 1/2 turns out before start up. Fine tune them.
Then, do your vacuum synch.
I made a detailed post on bench synching the VM carbs at another thread, but I didn't save it. If interested in it, do a search. The thread is in the technical section, authored by "Hoomgar", title is something like: "GS1K re-jet, poor fuel mileage, attn Keith Krause".