The P/C are aftermarket. And yep, the new plugs were gapped correctly. I'll try dragging some paper between them to clean them as suggested. I also have a new emgo coil coming in, an OEM replacement instead of the orange universal ones, so I'll throw that in just as a last resort before I look into replacing the source coil.

I’ve had good luck and bad luck with aftermarket P/C so now I buy Yamaha now if it were mine I would see  if the new coil worked if it doesn’t I would take the stator apart and clean and double check the wiring I personally have never had a source coil go bad

Condenser especially suspect. Some new stuff isn’t very good quality. 

I probably said this already but I’ve never had a bad source coil either… except ones damaged by someone using a jaw puller through windows and most of those even work. 

I should say, I tested the condenser that came out and it tested okay. So I'm moving away from points/condenser and towards the ignition coil and source coil again. 

I'll replace the ignition coil with an emgo unit made to replace the OEM one (instead of a universal one) and I'll disassemble, clean, and reassemble the stator/coil. 

And just for my sanity....the source coil is the coil on the right side (if you're looking at the stator plate mounted head-on, the rearmost one), correct!?!

I feel like i'm running out of options here!

No!!, looking at the pic on page one its the coil on the left. Fat one is lighting charging. I'll go look again incase that's someone elses pic not related.

Coil number 6. Numbers aren't that clear.
www.partzilla.com/catalog/yamaha/motorcy...wheel-magneto-dt250a

 

Yes the left coil it has thicker windings that’s how I remember in my old age Ha Ha

Think you said somewhere that you spun it with a drill & got intermittent spark so that says things are connected up correctly but not producing enough voltage--or bad connection. I dunno. Always wondered if they'd run as 6 volt battery ignition with the right two wire plug coil & let the lighting coil charge battery as it does anyway. Might try it sometime.

I'd better not carry this on haha but 'i think' the wire gauge of the source coil is slightly smaller than the lighting but only going by memory. Deffinitely less windings overall than the lighting. Here's a coil for you if its still a current auction or sale.
www.cmsnl.com/yamaha-dt250-1974-usa_mode...ilsource_4388131220/