It could be a bad stock fuel Petcock valve. It is located just below the left hand side of the tank. When the diaphragm in it gets bad, it causes a variety of illnesses.
Oct 02, 2013
Carburetor by: RobG
It's not operator error! Your carburetor is out of adjustment. It sounds like it's getting flooded, the float is sticking, and that's why fuel is coming out. But there's likely more to it than that based on your description.
I'm no carburetor expert, but since three of my bikes have carbs, I've had to become proficient with them. My best suggestion is to have somebody knowledgeable about them pull yours and disassemble it, clean it, and make sure everything is right. If it's particularly old, it might need a rebuild (not expensive; it just means new jets and some rubber seals/gaskets). But once that's done it should run like a top!