Draining the carbs before storage is the right thing to do. But, it does allow any residue in the carbs to harden up. So, the float pivots could be stuck, the float needle could be stuck or a little piece of crud is blocking the float valve from completely closing. Certainly removal and cleaning will correct this problem and if you are eager to wrench, do proceed. However, sometimes the, now drenched, fuel bowls will soften things up inside the carbs to free things up in a day or two. Also, if the overflow is not too bad, operating the bike for and hour or so helps to flush out the carb, too. The machine's vibration and normal gas flow will do a bit to help keep the carb internals clean.
So, do drain the carbs and examine what comes out for contamination. Keep filling and draining the bowls until the discharge is clean and clear. There is some risk that the smallest orifice in the carbs, the pilot jets, will clog with any remaining debris during the run. This is why draining the bowls clear is done before any run period. The idle jets don't get their feed from the bottom of the bowl, but a bit higher up. In short, sometimes, not always, just operating the bike will get it to behave properly.
Unfortunately the "remove the pilot screw and squirt carb cleaner into the hole trick" won't work with your carbs, as they have a different physical arrangement than the carbs on a 75 CB550.
Cheers,
