you need to find outy if its spark is missing when its broken down,when it does it next time make sure you have a 21mm plug socket and undo the plug take it out put it back into the ht cap earth it on the frame or engine on a metal part and kick the engine over and see if it sparks,if it doesnt i would say it very likeley to be the primary ignition coil in the stator coil assembly ,if it still sparks them i would look at the fuel flow try it with the petrol cap off in case there is a negative pressure(vaccum) build up in the fuel tank that is stopping the flow of fuel to the carb.let us know please what you find.
adam bike doctor, January 2010
