Has the gas in the bike sat for a long time? If gasoline sits too long it starts to go bad, and will gum up your carbs. You should drain the entire fuel system, and maybe add some carb cleaner to your first tank. The reason it will run on choke and notnormally is that the old gas is gumming up the carburetors. When the choke is on, the airflow is reduced, and the carbs can keep up. When the choke is turned off, the fuel delivery won´t be able to keep up with the airflow.