I take it you didn't start the bike up at all before September then? Hmmm they could be trouble ahead then. When you put that stabilizing fluid in the tank did you run the engine so the stabalizing fluid went into the carbs? Looks like you'll be calling on the Thunderbird team again next spring.
I bought myself some and I've got it in my tank now so I'm looking forward to see how it is in a months time when I start the bike up.
Bit of advice. Buy a good bed and a good pair of shoes, because if you aren't in one you'll be in the other.