No electrics

I have just rebuilt my px 200e, non batt. Problem no electrics apart from the horn. All the wiring looms seem fine and connectors and it starts ok. Have checked wiring on the regulator,cdi box and stator plate. All ok. There is a wire that comes from the stator plate. Black that has nowhere to go. The 2 green red and white connect ok and the blue. I have tried a new light switch. Nothing at all. All connections are fine under the horn cover. Any ideas anyone. Thanks.

The black one is your earth it should join your loom above the flywheel (little black connector box) and then it goes to your regulator (or a good connection on your frame).