Point contacts are curved and tungsten plated.
Curved to prolong life. Tungsten for high temp oxidation resistance.

Make powers iggy coil to saturation at best.
Break kills power to the iggy coil to collapse mag field at the iggy coil.

The more saturation, the better.
The faster collapse, the better.

To help this collapse, a condensor, matched to the coil eliminates sparks at the points at break point.
The condensor also "rings" with the coil until resonance providing a couple extra pokes at the spark plug for prolonged ionization.

Simple LC circuit.

Don't ask me about carbon nano tubes!

cliff

Automan, what you described is true for the AT1 12v electric start models with the common Kettering type battery powered ignition system.

The Yamaha ET (energy transfer) magneto works pretty much exactly backwards from that... stator coil output is grounded through closed points.  Stator coil and magnets are timed so that the AC sine wave output generated is just peaking when points open.  This "surge" of power (and some sort of inertia effect) creates a sudden magnetic field in the ignition coil primary winding.  This sudden field creation (not field collapse) is what induces high voltage in the secondary ignition coil windings and Viola!  Spark.

When you did the battery trick to get spark from the plug coil were the points 'not involved' or lifted away from earth. Sorry, just asking.

I did not have anything (like a business card) wedged in there holding the points open when I got the battery trick spark.

Ok so holding them open is same as having a card in there. So your two batteries were just energizing the plug coil--well condenser too i guess. Probably confused the system
On second thoughts Maybe i read your answer wrong sorry. So you mean points were closed?. Was thinking you meant held them open by hand. I'm having a Thick Day lol. If points 'were' closed & contacting i'd think that'd be a dead short scratching a battery anywhere that lead to the points, be it condenser or lead into the plug coil primary.
I'm forgetting what the subject is--right--no spark. I won't go confusing things more than i have, but i've used a lighting coil to power up the ignition when i thought the sourcy thing was faulty but wasn't convinced although found no other faults so by lighting coil powering it she gave good spark, almost too good.

Just for clarity, I'll detail everything. I replaced the condenser and points with new ones from Yambits. Don't know if that's a good source or bad source in everyone's opinion, but that's where I got them. After hooking everything back together, I had no spark when trying to kickstart. So, I next replaced the ignition coil under the tank with a new Hitachi one (Yamaha Hitachi coil, SKU: 140-B-YA17206) from a Netherlands company, JMPB Parts. Still, no spark when kicking. Using the D-cell scratch trick is when I get a spark.

Some Yambits stuff is good, some is crap. I would replace points and condenser with original or Daiichi repro - both are usually available on fleabay.

I think you already answered your question. If your points were actually making contact, you could not get spark with your battery test setup, as the current from the battery would be shorted to ground, just like it is from the source coil when points properly make contact. As Mark said, dirty (non-contacting) points is by far the most common problem causing no spark. Clean your points, then verify with an ohm meter that they zero resistance when closed and the circuit has 1 or 2 ohms when open (the resistance value of the coil of wire in the source coil)

Ideally the only thing not replaced is the source coil.
So providing points are contacting when closed & not contacting via a short at the wire post when open & points cam 'is' opening & closing them each lap, then blimey i dunno.
Solder not dribbled over to the condenser body.
Think i said i've wired in the lighting coil to test the theory of a faulty source coil but I shouldn't teach bad habits of things i do in desperation.
Somewhere i have a video of cranking my old 175 i think it was. It shows the voltage output & pretty sure i showed it with points bridged then did it again unbridged & ready to start, which is something you could try.
Too tired to go looking now but i'll find the post & link it tomorrow if i can & if it helps.

Is this my problem you think?

flic.kr/p/2pNZzwV