Sean,

>My first thought was "aw sh*t, I gotta drop the tank" but further
>inspection showed that the only thing leaking was one of the rubber
>cloth-covered hoses that leads to the vent tank in the driver's wheel
>well.  That one hose was soaked with gas while the others were dry, and
>I didn't see any leaking on the passenger side.

>So, I have to replace one hose.  No big deal, it's in plain view and I'm
>happy.  The question is what size is the hose?  Looks like about 7mm.

It's a 5.5 mm inner diameter hose. You should change all rubber hoses.
The rubber hoses may dried out of a '81 Westy. I changed all recently
and they ALL looking odd. You don't have to drop the tank for this work.

Helmut
'80 Camper