Wouldn't you know it - no spark!

Argh. So got the rig all put back together again last night. Or, at least, mostly back together again...seems like I'm not getting any spark. Electrics are the bane of my existence, as I don't really understand the systems fully, but I'll try to lay it out as best as I can.

Bike: '78Kz100A

The only intentional change I made to the electric system, was to swap in a new combo reg/rect from Jeff. And I'm reasonably confident that I have things at that end of the bike wired up correctly. And, other than the new reg/rect, it should be the same and it was definitely running when I took it apart. Though I did take it apart all the way down to the frame, so it's anyone's guess what the hell i fouled up.

All of the lights work and the starter turns over like a champ. I'm pretty sure I have the Dyna S coils wired up correctly as I took good pics of those and the connection to the three part connection that runs to the lower right (ignition?) case.

One thing I did not document very well that seems like it could be wonky is the wiring coming from the kill switch on the bars. On my harness this is pretty much hard wired into the harness. there are three leads coming from the switch...a red, a black and a yellow & black.

Both the red and black seem to be well linked into the main harness, but the red & yellow connector isn't hooked into anything and, for the life of me, I can't find a corresponding connection.

I realize this may be nothing more than a red herring. Any recommendations or best practices on how to start to unravel my spark/starting woes would be greatly appreciated.

red/yellow wire is supposed to feed battery positive voltage to the coils when ignition switch is ON and killswitch in RUN position.

Coil can't function without voltage supplied to its primary terminal.

The problem isn't related to the reg/rec. And engine ignition system will perform perfectly okay on just battery power until the battery runs down. Same as if the alternator (aka dynamo aka stator) and regulator and rectifier are completely removed from the bike.

Would trace voltage in red/yellow wire to determine where it gets interrupted before reaching the coils.

Good Luck!

Damn straight -- more sleuthing yielded a buried red/yellow receptor for the lead that i had missed. I gots ta clean up that damned rat's nest of a wiring harness under the tank...shameful.

Thanks again Patton for the sound advice!