I started tearing into the B4 today -- finally!
Have a look at this pic:
I think line 2 is the vacuum line, since one end went to the petcock and the other connects to the carb boot. Is that right? It flows fine.
Line 1 connects to a T at the rear of the carbs, between 2 and 3 (dead center). I couldn't tell if the other end was connected to anything... should it be? When I blow into it, the two holes on the lower lip of each carb start to spew fuel. So I wonder if this is just a breather that remains open on the other end.
I should say "is supposed to" remain open on the other end. It was pinched flat under the tank when I took the tank off! Wonder if this wasn't part of my problem...
Plugs are fine. I replaced some fuel line while it's open -- no more dry-n-cracky, by cracky. Next stop is the sediment filter in the petcock. Damn, I hate smelling like gasoline!