|Ignitions Pickups Grounding Out on the Engine Case by Stretch
The ignition usually advances in steps dictated by the number of steps on the flywheel, airgap and at which revs the output of the pickups triggers the threshhold in the ignition modules.
The most common problem in Pantahs is the deterioration of the pickup wires - easily determined and fixed.
The more annoying problem is if one of the wires earths itself. The ignition will fire but will not advance. Check with ohm meter if the pickup resistances are in the ballpark (about 250 ohms I think) then check if one is making comtact with earth.
I discovered this when I found that my "extra insurance" blob of high temp silicone used to secure the pickup wire insulation which were beginning to fray and then discovering just how close the LH cover comes to the pickup wires. Now I route the wires down the sides of the pickups rather than down the back.
ed note: Also make sure that the pickups generate a positive voltage trigger to the ignition system. This can be checked by looking at voltage across the ignition pickup terminations at the ignition modules. As you spin the motor the running direction, you should see small ( ~a few mV) POSITIVE pulses being generated by the pickups. At the ignition module, check across the two trigger leads. Neg (-) is the center ig module terminal, Pos(+) is the other terminal. If you see negative pulses, switch the leads.-ed the ed.