New stupid problem:
Took the bike for a 40 mile each way trip, today. The whole way there, ran like crap. Got to my destination, took care of business, went to gas station.
Gas cap wouldn't come off. Seized to the point the whole thing unscrewed from the tank; peeling the paint in the opening with it; leaving paint flakes in the opening and, most likely, the gas. I was able to refuel, but still have the issue of the gas cap is completely stuck in the structure that connects the cap to the tank.
The way back, the bike ran much better.
I'm guessing the issue may be old gas (was out of SeaFoam at last fillup) combined with massive fluctuating of temperatures. The last time I completely refuled was early October; and it was warm, 80's. Since then, the temp has gone from 25-90 a few times. Today was 50 when I left.
(The bike only got 40 miles since the last fillup in October; mostly a bunch of 2-3 mile trips in town, riding in all kinds of temps/weather).
The fresh gas seemed to burn better.
I presume the expanding and contracting of the gas cap inside the structure is what seized it.
Any ideas on how to get this unstuck? Thus far, I've managed to bend a pair of needle-nosed pliers and scratch the outer ring with a nice deep gouge, cussed a lot, and still have a very stuck gas cap.