Have been using an 08 KFX450 and haven't experienced any issues. One day, while it was being driven, it just died and wouldn't start. I have been reading on the forums for solutions, and have checked fuses, main fuse, relays and rollover sensor and no luck. It does not make the priming noise when I turn the quad on, and the starter works fine, but fuel pump seems to be not working properly. What could the issue be?