If a hose came off or split, you will see/hear the gas splashing around in the tank when the bike is turned on, filler cap open. If it's not that, I'm inclined to say those are the symptoms of a swarfed up Crank Position Sensor, other than it started up and then died, but the turning over and not sparking all of a sudden/out of the blue, sure sounds like the CPS should be pulled and cleaned off. It's the sensor to the left of the water pump, behind the hoses. It can be pulled out and replaced with the hoses attached, but not without some dififculty. It may be worth a try.