TOPIC:

I picked up a 1979 kz650, aka Mad Max. The guy I got it from
said it had issues with the #1 cylinder, I ran a compression test, it checked out, so I assumed it was a bad coil, and the guy said he had never even changed the spark plugs, so I figured there was an outside chance that it was as easy as a new set. On the way home I picked up new plugs, and tossed them in as soon as I got home, I pulled all the plugs one by
one, the spark was weak, and unsteady, on 1/3. Next I tried to start it, and found that the starter button doesn't work, but I crossed the solenoid and got her to fire and idle for a few seconds, than it died, and wouldn't start. I pulled the #1 plug, and cranked it again, it sparked one time, an orangeish colored spark, and than nothing, checked the other plugs, ditto. So, I figured the coils had gone. My friend had a 1980 kz650 parts bike that had ran last year, so I bought the coils off of it, they're different, the bolts are further apart, and it has blade style male connectors instead of being directly wired. I hooked them up. Still nothing.
I noticed that my main fuse had popped, and I replaced it.
Still nothing. I also bypassed the thumb kill switch just to make sure that wasn't the culprit, didn't help.

So thats where I am now. Any Ideas?
All input is greatly appreciated!

Would first assure battery is good, fluid levels correct, and fully charged, with clean tight terminal clamps and good soild ground where battery wire from negative terminal attached to engine or frame.

With engine off or at idle rpm, voltage measured across battery terminals should be at least 12 volts. At 3000-4000 rpm, should be 14-16 volts.

With engine off, voltage at coil primary should be same as battery or only slightly less attributable to old wiring and old, loose or crusty wiring connectors.

Could spray water mist over plug wiring with engine running in a dark garage to see any sparks evidencing current leakage.

All toward assuring sufficient voltage is getting to the coils, before worrying about whether the coils might themselves be defective.

Good Luck!

De ja vu!! For a number of checks and good info check my thread "Coil check question"

Thanks for the tips. I was using a brand new battery that I pulled out of the gt750. So, I'm pretty sure I'm good there.
I'm going to replace the ground and + wires. I'm getting the stuff together to do that W.G. ignition mod too. Do you think that might fix the problem?