38mm mikuni 34 mm slide carb

I have a 1975 xs650 with the original 38mm mikuni carbs, K&N filters, worked fine for 46 years, until the pandemic, bike sat for over a year, carbs full of gas, gas corroded and gummed up carbs, now it won't run, wont even start. I have thoroughly cleaned the carbs, and appear to be normal...