persistent and odd fuel ration

Carbs are rebuilt and clean. Coils are brand-new Dynatek, points replaced with electronic ignition. Plug wires are new. Choke plungers rebuilt. New fuel lines, new spark plugs, and a Pingel dual-outlet petcock.I am not trying to turn carbs into fuel injection.At idle, the bike audibly stumbles, and that stumble happens at the same moment the AFR spikes. I don’t know which is the cause and which is the effect.Cylinder #2 shows intermittent pockets of lean AFR. Cylinder #1 does the same thing, but to a lesser degree. These traces are all at idle (~1000 RPM). The issue largely goes away if I raise idle speed to ~1200 RPM.The bike is fully warmed up, but the issue is worse when cold. I don’t believe there are intake or exhaust leaks. Carbs have been synchronized.For reference on the graph:
• Green ≈ 12 AFR
• Red = anything above 14.7 AFRThis puzzle probably has nothing to do with jetting, and I’d prefer not to go down that rabbit hole—but for completeness, here is how it’s currently set up.Dec 20 update (after rebuilding choke plungers):
Everything seems to go lean on throttle snap.

• Cylinder 1:
  (Pilot 10 / Main 100 / Clip 2 / 3 mm)
  Small AFR pops at the same frequency as #2, but much smaller. Otherwise AFR looks good.
• Cylinder 2:
  (Pilot 12.5 / Main 102.5 / Clip 3 / 3 mm)
  Large AFR swings—almost like a backfire, but still within range.
• Cylinder 3:
  (Pilot 10 / Main 105 / Clip 4 / 3 mm)
  Perfect idle.
• Cylinder 4:
  (Pilot 10 / Main 105 / Clip 4 / 3 mm)
  Idle is too rich; pilot screw is almost fully closed.

Looking for insight specifically on the intermittent lean pockets at idle and the synchronized stumble—not general jetting advice.
 

 

This effect (at idle) can be a result of weak spark. Have you verified that the supply voltage to each coil is stable, and within 0.5V of the battery voltage (12.5V to 13.8V).
Higher (than normal) resistance wiring ( ground and power) to/from coil terminals, CDI and voltage regulator will be the culprit, or, possibly a failing battery or charging system.
Also, verify plug gaps are correct (0.6 to 0.7mm)
 

If I am reading it right it's no surprise performance is bad, your jetting is not consistent