Motorcycle Repair: carb runs over, hairline cracks, air vent

Question
Hi Wayne i got a 1987 xv700c a couple of mpnths back and it had sat for over a year with gas in it. i took the tank off and cleaned it and removed the carbs and put them in carb cleaner to soak, they cleaned up real good. i got new carbs kits and put them in and then when i tried to set the floats the front one is set ok but the other one keeps leaks running over i have to set the float so that the bowl is only 1/4 full to make it stop leaking,i put in a second neddle and seat and changed the floats around and the front works fine but the other still leaks. i took the tank off and the carbs and placed them on a bench and hooked up the gas line to the leaking carb. and if i pushed up very gentally the gas would stop running and there were no other leaks.have i done something wrong when i rebuilt the carbs. Thanks Roger

Answer
Roger,

-Check the float bowl vents, make sure
it has a clear vent. A plugged air vent
in the carb body might make it push fuel
out.
-check the carb gasket and check the float bowl for warpage.
Could the float bowls be switched, any hairline cracks?