So when I was going thru everything to bring this amazing machine back to life I had spark so I left the original Mitsubishi points in place despite coming in at a way below spec gap when at “.126 BTDC. 

After tweaking and optimizing everything other than the ignition I have a bit of a breakup when over 6000 rpm so my thinking was that the too narrow points gap was contributing to this either because not enough primary saturation time, bounce or both. So I installed a new set of Daiiaci points and reset timing with dial indicator and now this bike hauls ass right up to redline and I have to lay off the throttle at around 70 mph out of fear!

so my question is, isn’t the points gap “is what it is” when timing is set since gap and timing are not independent since stator isn’t slotted?  This was my take so once I got new points set to precise timing I didn’t even bother to check gap since 1. The cam follower is new and 2. Nothing I could do about if if not in spec. 

make sense?

why not a slotted stator to enable setting gap to maximize ignition output and to optimize timing?

thoughts? 

her is my new gal, I love her!

 

You're right, timing sets the gap. As the points wear over time, there comes a point where you just can't get to the sweet spot and then it's time to get a new set.

I watched member DVM set timing by sight & feel "in the field" (at a group ride), peeking through the flywheel window, watching when the points open against the pointer & "feel" of the flywheel's movement when rotating it. His method worked just fine. The more you mess with these bikes, the more natural these detailed adjustments become.

Because the points need to open when the magnets and coils are aligned so that the voltage is at or near max when the points open. 

I've seen a bike with worn out points and slotted stator that had the gap in spec but a very weak spark because someone moved the slotted stator to the end of the slot to compensate for the points wear.  I put the stator back near the center of slots and installed new points and strong spark was back.

that is a very interesting nuance Mark, thank you
the timing of the magnets add another twist over old points set up that I grew up with where you set the gap (dwell) before setting the timing because dwell changed timing, but timing didn't set dwell.  So the idea of setting gap then setting timing via slots wouldn't necessarily work in this case, unless points following block/tolerances were in spec, in which case slots wouldn't be needed 

 

Dwell is more or less irrelevant with these systems. 

Ignition coil is just a step-up transformer.

The common Kettering (battery) ignition I'm sure you're talking about requires the points to be closed a sufficient time to "charge up" the primary winding in the ignition coil so that when the points open, the sudden collapsing magnetic field of the primary winding induces high voltage in the secondary winding of the ignition coil which creates the spark. 

The Yamaha ET magneto system relies on the points opening when the AC voltage in the stator winding is peaking.  Points opening allows this surge of voltage to flow to the primary winding of the ignition coil...  The sudden creation of a magnetic field in the primary winding induces high voltage in the secondary winding of the ignition coil and again you have spark. 

When your points wear you can adjust them to get the timing back in spec but now they may be opening when the stator voltage is less than it could be so the spark is weaker.  This is not really an issue until the max point gap gets out of spec like yours did. 

So best practice is:  Set timing to spec.  Measure max point gap.  Gap in spec range?  Done.  Gap not in spec range? Replace points and start over.