it has a fuel problem i suspect you will need to remove the carb and strip it and make sure all the jets are clean ,has the bike been standing ?also a faulty stator coil assembly can do this but it will usually run for a minute or two before it cuts out.make sure the fuel in the tank is fresh and has not been standing for more thn a couple of months or it will need to be changed for new petrol
                 adam bike doctor(of milton keynes motorcycle centre)
                
 June 2011