does the petcock have a vacuum on it, or does it have an "off" setting? You're likely getting fuel overlfowing the carb float, going into the cylinder, and seeping down into the oil around the rings. Definitely don't try to start or run the bike until you've changed the oil and check the cylinders. Sometimes the cylinders are full of fuel, and when the piston tries to compress it, you bend things inside.
Start by disconnecting the fuel line from the petcock and see if fuel keeps seeping out. Next have the carb checked. If you are fouling plugs, it's either because of the fuel leaking in, or your carb is running rich.
Start by disconnecting the fuel line from the petcock and see if fuel keeps seeping out. Next have the carb checked. If you are fouling plugs, it's either because of the fuel leaking in, or your carb is running rich.