I've been doing a little studying on this subject, and I'd like to make sure I know what I'm doing before I dive in. Maybe some of you with more experience can confirm or correct my understanding of the process.
1. In charging the magneto, the goal is to restore the full strength of these permanent magnets on the flywheel.
2. As the flywheel turns, those magnets spin by this coil ring and their magnetism shoves electrons from the coil ring through a circuit. This is the current that powers the ignition system.
3. There are three ways of recharging the magnets.
A. With the magnets in the car, pass a DC current through the coil ring by way of the mag post, causing the coils on the ring to acts as electromagnets to charge the magnets on the flywheel.
B. With the magnets in the car, remove the transmission cover and recharge them with a charger like this one by James Golden.
C. With the magnets out of the car and perhaps off the flywheel, recharge them with a charger like the one above.
4. Methods B and C are better than A because the charger restores more magnetism by being in physical contact with the magnets, while in A there's open space between the magnets and the coil ring.
The magnets can easily be recharged out of the car by laying the coil ring on the assembled flywheel / magnets and applying 36 volts for a split second.
I have used the method that Royce describes. The first step should be to fully disassemble - Check the magnets and flywheel for cracks - re-assemble with new hardware - set magnet heights. I place a small voltage on the mag ring and lower it onto the flywheel. It will self-align to the correct polarity. Then I hit it with the full voltage. I have also taken a bronze hammer and gone around and given each side of all the magnets a fair "tap" while the mag coil is energized.