Having cut my motorcycling teeth on your bikes predecessor (the m) and having learn't a few of the gremlins.
Make certain the cap its self and cap to lead connections are good, have a couple of proven plugs to hand even if they are from cars. Check the earths, esp if the frame has been re done, they can get covered. Even run a temporary one from the HT coil to the engine, (NOT the battery) if its easier for now.
Disconnect the kill switch at the headlight so your sure that isn't tracking, crank the bike over a couple of times in the dark to see any sparking at the points, there should be just a little, you may catch sight of other unwanted earth tracking around the engine.
Lastly, does it actually run at all?.