It sounds like your problem is the stator. Seems like you have done everything else, fuel, plugs, kill switch etc. if there is no spark at the spark plug then your stator is simply failing to produce a spark. I recently had to replace the stator on my sons 2001 ktm 65sx. I had to go through all of these same checks. The stator was the last thing I wanted to replace because it was a 500 dollar part. Once replaced it fired up first kick.