As Ned says you don't need the battery or nearly any of the wiring harness for it to run.
If you wanna test it then disconnect the battery and also the yellow and blue cables fron the ignition. Just connect the Red, black, green on the SEM to the coil. You can even disconnect the kill switch from the coil (not sure what model your on but it's orange on mine) to take that out of play. It should still start and run but you won't have any other electrics.
It really does sound like your stator going bad so you should check all the ohm readings of the coils with a meter.
If the SEM checks out OK then I would remove the coil, regulator, rectifier and the main ground cluster connector and clean all the ground connections thoroughly - believe me this is a major source of electrical gremlins.
Coops
If you wanna test it then disconnect the battery and also the yellow and blue cables fron the ignition. Just connect the Red, black, green on the SEM to the coil. You can even disconnect the kill switch from the coil (not sure what model your on but it's orange on mine) to take that out of play. It should still start and run but you won't have any other electrics.
It really does sound like your stator going bad so you should check all the ohm readings of the coils with a meter.
If the SEM checks out OK then I would remove the coil, regulator, rectifier and the main ground cluster connector and clean all the ground connections thoroughly - believe me this is a major source of electrical gremlins.
Coops
