Man I know your frustration:
Mine had the same problem, I had spark, it was in time, tried every combination of choke settings. Peddeled around the block gas turned off and plug removed. Thought I was going to have a heart attack it wore me out so much. Tried for a week and called Criss at Bike to Moped, where I bought the motor, he said to change the plug, which i had already done but got the right one and got it to start, but it was still a all out effort. My intake gasket was also leaking. It dosnt take many trys to foul a plug when breaking in with that high oil mix. I would get the correct new plug, take off the intake and seal with high temp sealer if the gasket is there, or make a new one if it is not. Then 3/4 choke and full throttle for a good half block or more, If no start then no choke on the return trip. I would never thought sence I had spark my plug was fouled, but it was, not hot enough spark to start. That leaking intake was the biggest problem, also check to be sure the carb is fully on the intake because of the grove that is cut will let air in. Good luck, Im sure you will whip this problem.
