Running Issues

[Howie]

So it's not necessary then.
What exactly is the point for it?

The point is to shut automatically off fuel when the bike is shut off and turn fuel on when the bike starts.  If a carb needle and seat fail open when the bike is not in use, particularly in transit fuel will run onto the street, creating both a possible fire hazard and environmental damage.  You now have a manual petcock so the vacuum fuel shut off is a redundant part that reduces reliability.

[Jdan]

Ah, okay. Thanks for clearing that up and the rest of the help with the bike.