I have a problem that seems to be getting worse. My bike fires up first flick of the button - cold (with choke) or hot. However, after running perfectly it will cut out without respond to applying throttle. Hold the finger on the button for 2 seconds and it fires up OK. Ride for 1/2 hour, come to a stop and dies - no throttle response. Hold starter button for 2 seconds and fires up and runs OK. It's like there's no fuel getting through. Anyone else experience this, and more importantly, anyone got an answer?