Remember, engines are simple, they only run one way. Fuel, Air, Fire(This includes timing). If you have good, strong, and consistent fire, then your issue is either fuel, or air. I'm working on an older Kawasaki KE right now, that wouldn't fire unless there was NO gap on the plug, and even then really wouldn't fire consistently when in the engine, my issue was that water had flooded the left side cover, and soaked the stator and points, cleaned them up, sprayed liberally with WD-40, and she fires up first kick now.
Here's a tip, spray the anode of the spark plug with a bit of starter fluid, enough to be visible, ground it, and see if it sparks enough to light that bit of starter fluid, if it doesn't, then there's your problem.
This is my trike. There are many like it but this one is mine. My trike is my best friend, and it is my life. I must master it as I must master myself. My trike without me is useless. Without my trike, I am useless. I must ride my trike true. My trike and I know that what counts is not the amount of miles we ride, but the time we ride together. My trike is human in it's own ways, therefore I will learn it as my brother. I will learn it's weaknesses, it's strengths, it's parts, and it's soul.