Yeah, stuck float or dirt under a float needle valve (use an inline fuel filter) or worn float needle valve (cheap and easy to replace) or worse case is that the brass overflow tube which goes up from the bottom of the float bowl is cracked - still an easy fix.
My suggestion would be to take off the carbs. take off the float bowl(s), remove the float and float needle valve, dip a Q tip in carb cleaner and run it around the brass needle valve seat and around the tip of the float needle itself. Check the brass tube for leaks. put it sll bsck together and if it still leaks order replacement float needle valves and replace. Also - manke sure the floats are not getting hung up or sticking on the edge of the bowl.
Good luck.
1980 kz750E1, Delkevic exhaust
