Yes, make sure to check that the wires in the harness that you connected to are the right ones... I looked at the wiring diagrams and they show a black wire from the CDI plug you tapped into that goes to power the ignition coil. I'm almost 100% sure that wire is actually orange.

I could be mixed up though. Wouldn't be the first time.

So I hooked up the jumper wire and no spark. Am I correct that by using the jumper the no spark problem is isolated to the ignition coil, source coil, points and condenser? I rechecked the source coil and it is 1.7 ohms at 68f, points open. Is that close enough to the spec of 1.5 ohms? Points are new and gap is correct. Condenser is new although I don't think I checked it before installing. Is there a way to check it on the stator?
Plug and cap were off. Just had the snipped off wire from the coil against an unpainted part of the engine. Thanks!

Not sure but think the way you're testing the source coil resistance you're adding the condenser resistance into it. But i wouldn't worry if they're all new bits providing nothing is shorted to ground. Forget about the wiring loom for now & just run the black wire from the points/coil/condenser straight to the plug coil under the tank & see if any luck.

Did use the jumper wire as suggested but no spark. I did test the source coil with the condenser installed. Do I need to remove it to properly test the source coil? Thanks!

I don't know [old & confused] points systems are so reliable. My couple of random looks at two similar systems are DT3 source coil Black = 0.508 ohms [only a bit over half an ohm] but CT3 [which i thought'd be very similar] says 2.1 ohms so i dunno. Let's assume all your bits are A ok. so is there a chance you've fitted the new coil flipped end for end as that'd muck it up?.
Here's a random link i found which isn't realy any help--just googling away. Just check it for flipped over. did it come with an earth screw mount attached or just two bare wires.

advrider.com/f/threads/anybody-to-help-w...ition-issues.909634/

Don't forget to clean the points. Even brand new ones sometimes get a nonconductive film on them

Sorry, I am a bit lost. Not sure what you mean by flipped end for end. Are you referring to the source coil or the ignition coil?
The Emgo ignition coil came with a mount which I had to modify to bolt to the bike. I checked and it is grounded.
Apologize for my ignorance here. Can you explain? That very well may be the problem.
Appreciate the link. Thanks

Hi, sorry, yes talking source coil on the stator plate. was wondering if it's possible to fit it wrong or is it just too obvious which way it goes. Looking at the parts pic for a "74 it shows the earth side of the source coil heading into the lighting coil. This was a Yamaha trick to earth it via the lighting coil but i'm not sure why. Years ago i had an earlier 250 with a faulty lighting coil [loose & jangling on the pole its wound on] & was causing an ignition misfire & terrible running, so i earthed the ignition source coil separately & misire was ok after that. I'd guess [looking at the parts pic] that both wires come out of the source coil at the rear of the coil for it to be correct.

Thanks! I get it. Not something I considered. I'll check it out. Appreciate the help!!!