The 2 wire system is easy, one is a frame ground - easy enough.
The second is between stator and coil ."After 05" it is black with a yellow stripe. Remove some plastic coating and solder the 2nd wire in place. Then coat exposed area with black silicone. Walla!
Be careful using wires near a coil. You dont want to ground a high voltage wire because things may melt .This is bad for your machine.