Spark Problem

it could be a number of things. a faulty ignition coil or ignition coil ground wire. faulty cdi unit or stator coils. or something as simple as a lose or dirty electrical connection.
 
check spark then if you havent removed TORS, remove it because if its not the spark plug, thats like what its going to be, 85%
 
I forgot to mention like 89custom said, when mine messed up is also when I discoverd my tors went bad. If you don't already know, you can try unplugging the brain and trying it, I believe its the one above the CDI.