Your stator or magneto is the electrical powerf or your scooter when ever the engine is turning. Created by coils of wire with a fly wheel going around coils producing electrical power. Same as alternator in your car.
The stator charges battery also at 13.8 through voltage regulator plus pick coil is here also providing plus for CDI/Coil for spark to spark plug,
There are three different versions of mag for the GY6 50 139QMB it all is in the wiring.
White connector and seperate wires in these
3+1
3+2
2+2
There are also insulted coils which on some there are two and others one so its good to notice this also.
The newer scooters could have no insulted coils and one seperate wire besides white connector.