as Wayne says, very most likely float needle valves leaking. your float level adjustment would have to be really off, to overflow out of carbs. if carbs were not leaking before and now they are leaking, i can't imagine anything but gas getting past the float valve's needle & seat. i use small industrial wooden Q-tips lightly dipped in Simichrome, insert cotton tip in to needle seat, spin the Q-tip between my palms. or, at least i used to... what i actually do, is chuck the wooden shaft of Q-tip in my Dremel and w/ light pressure shine the seat. with the crappy gas nowadays, if the bike sits any small length of time, debris can form from gasoline degradation, particularly where ethanol is part of gas. and, i have seen on numerous occasions, new Honda needles and seats leak. when i have carbs off, i always bench test them overnight to be certain the float valves are not leaking. and i do not set up carbs by float level, but by fuel level. i know some guys only use float level, but in my experience if you want to know exactly what level the fuel is rising to in the bowl, then fuel level is the best accurate measure.
if carbs sit over winter months in a non-temp controlled environment, it is even more likely fuel will degrade, and debris will form in carbs. A gas stabilizer should be used.