4onthefloor and CatDog; thanks for your inputs regarding this matter. There is no doubt she's making pressure. Caused a small leak in the vent tube where it goes into the tank which completey disappears when the cap is left loose. I got the vent tube fixed (not that it really needed it).
I'm on the hunt for a good cap now. My old BMW bikes usea nice cap made by Blau and it uses a nice cork gasket. Too bad they are a bit on the large side because they are beautifully done.

Thanks,

Tom

"old enough to know better"