Is the fuel pump primed? Since you have spark, my guess that it has to be fuel related... You can put 12V to the fuel pump with the prime harness inside the harness bag next to the oil tank. Put 12V to it and see if the fuel pump starts. I had to do this once to get it to start after the pump got starved of fuel and lost prime.
The other things to check is the wiring harness from the stator. My main harness connector had melted along with the plug down on the voltage regulator for the accessory (not related to your issue, but still something to check).