Need Help: Feuel or Electricity?

Took the '81 KZ 7590 LTD out for a spin today (it's 35 degrees here) which I try to do very weekend - to keep things running throughout the winter months. It was fine last weekend when I gassed up and put in a little "Stabil".
Now she's "missing" when I throttle up for power
Idling beautifully/cruising nicely
Only happens when I try to accelerate
What do I check first?
How do I determine if it's fuel or electricity?
Any relatively "simple" diagnostics anyone can recommend?

Thanks

Dave
NY City Vicinity

Hmmm. Running bad after a fuel up. I wouldn't think that an electrical problem would pop up that quick. I'd guess bad fuel. If it's bad when you get it, Stabil won't fix it. If you have a fuel filter I'd check that too. You may have gotten some dirt in your fuel. How confident are you in the station where you got the fuel? Was the tanker truck there when you filled up?

i would say its the fuel, fuel depots winterize the fuel with Methanol and my bike doesnt like it too much.
Nor does my truck for the matter.