carjac75

so i traded a mountain bike for this motor cycle which only has 6,500 miles on it about 4 months ago. got it cleaned up and ready to go. the carburetors have been nothing but trouble for me. i was able to get it running but then it would die and started to leak fuel. so i thought they needed cleaning. did that 4 times, replaced the gaskets, jets, needle valve and seats, the floats, cleaned the tank, put a fuel filter on it. they look clean as a wistle but i cant stop the leak unless i adjust the floats so there is hardly any gas in them, which then wont allow it to run over 6k rpm. i was reading on another forum which the bike sounded like it had the same problem and that someone mentioned it could be hairline fracture in the float bowl overflow tubes. is this possible? where can i get them? will this possibly solve my problem?