Mine has CDI ignition, so can't blame the distributor, but yesterday, a no start, checked the plug and no spark, then I noticed a rather poor system of connection between the plug wire and the part that goes over the plug itself. It just sort of loosely pushes together and is held that way by a rubber sleeve. When I pulled the plug, I must have pulled the wire a little ways out away from the cover. To me it seems a little half-assed, maybe the connection was better as it was first installed but I loosened it. Thinking of putting it together with a small amount of rubber cement to hold the three components together.
Another small problem was that it wasn't getting fuel. I must have disassembled and cleaned the carb three times, then as I pushed down on the lever, I cracked the throttle just a smidgeon and it started right up. Mine has a Dell'orto carb and the thin plunger that is attached to the slide enters into the very top of the pilot valve, so unless you raise it just a bit, it won't start. Also, it shuts down if you release the throttle completely. There is no kill switch, so maybe that is why.