yamaha doesnt sell just the carb bowl.
ab epoxy, jbweld, quick steel it is all prety much the same stuff. I used it to repair a crack in my raptors carb bowl. It would hold for a while but it eventualy will soften up and come loose. Permitex makes this gas tank repair stuff. It is like quick steel, the epoxy puddy that you kneed to mix it. That would be your best bet since it is supose to hold up to gasoline.
Permitex gas tank repair