Welcome to Ignition Info for 1970s and 1980s mopeds, USA models with brake lights.
The best resource for moped electrical is Moped Army Wiki. www.mopedarmy.com/wiki/Electrical
At left is an original 1974-1986 Tomos A3 stator, the stationary part of the magneto. Left is the points, right is the condenser, top is the ignition source coil (with two output wires, black and blue), bottom is the lighting source coil, with one output wire, yellow, at top right (not the yellow from condenser to points). The ignition source coil has an external ground (the blue wire), while the lighting coil has an internal ground (the solder joint at lower right).
More to follow…
Below is another Myrons hand-out sheet explaining internal and external ground ignition circuits.
How to tell if the condenser is bad:
This is a very useful troubleshooting technique. A condenser can be added temporarily without removing any parts. At left is a “Clip On Condenser” a valuable tool. When a running bike is having ignition misfires due to a bad condenser, this external condenser will reduce or stop the misfiring or “hiccuping”. It can be any older automobile condenser. It can be located anywhere along the wire that runs from the points, inside the magneto, to the spark coil outside the engine. It only takes a few seconds to “T” the condenser off the coil wire, clip the ground somewhere, and go riding.