1. Run the motor until it dies.
2. Turn off the petcock, and remove the bowl from the carb. Check the level of the fuel in the bowl, it should be full. -if it isn't full see (fuel)
3. Check the jet to make sure it didn't fall into the bowl. -if so just screw the jet back in
(Fuel) fuel supply issue:
- vacuum problem in the gas tank, that kept happening to me, try removing the gas cap and priming the carb with WOT until gas overflows from the valve, try to start it up, if that fixes the problem then drill a very small hole in the top of the gas cap. If you want to ride in the rain simply glue/epoxy a pop bottle cap on top of the hole and drill a small hole in the side of that.
- make sure that the gas level is above all points of the gas line and the carb
This is all I can think of at the moment, hopefully it helps.