before spend to much money check the fuel system tank(is clean ,the valve is clean )if you can make the engine running fine and it stop at 3000 rpm that mean wen the carburators are empty the fuel is not continiusly pooring in the carburators ,could be the gas cap also the vent system is plug off ok good luck I going to buy my vt 500 this evening real nice and cheap. ciao Michel of switzerland