Not sure I qualify as bright but here goes anyway !
What range is your meter set to ?
Unusual for the ignition generator coil to fail , I'd suggest just a simple set up first to eliminate the kill switch (?) or ignition switch - both of which short the black/white to ground stop the bike .
IE Just disconnect both and see if there is a spark with the engine wound over , if not check for an ac voltage from the generator with the coil etc disconnected , points clean & gapped ok , condensor ok not shorted ?
Tricky with a direct ignition set up as you need to kick and diagnose at the same time - best of luck !