If you let it sit all winter with E10 in the tank you are getting what you deserve. Over time the ethanol forms a layer in the bottom of the tank with the gasoline floating on top. Fuel preservatives slow the separation, but do not stop it. When you pulled the tank to access the carb, you temporarily mixed the ethanol and gasoline. Allowed to sit for a few minutes, the ethanol will settle out rather quickly the second time around. Result is straight ethanol in the float bowl, which will not run well, if at all, in an engine tuned for gasoline.
Solution is to dump the contents of the tank into a car or truck with nearly a full tank of fresh fuel for dilution purposes--best way to rid yourself of aged fuel in an environmentally responsible manner. Refill with fresh fuel and ride happily.
Best permanent solution is pre-emptive action. When you park the bike, turn the petcock off, hold the bike upright, and run the engine until it quits. Pull the enrichment knob, then restart to drain the dregs. Alternatively, you can mess with the drain screw, but that's usually asking for trouble from a stripped screw head. Fill the tank full to the brim with fresh fuel and stabilizer to minimize condensation. When returning the bike to service, drain the tank into a cage, refill with fresh fuel, turn the petcock on, and go. Much easier to do than messing with a carb cleaning every spring.