If you have spark only if rectifier is unplugged I understand that it is most likely a stator problem. Can you run the quad with it unplugged and will it cause harm to the electrics?
you are getting spark only when it is unplugged? ??? I honestly can't answer that one. I don't think it will cause any harm, but it shouldn't only work when unplugged. hmmmm
Anybody else?
You have a short between the HV and the charge windings of your stator. Unplugging the rectifier/regulator will eliminate the symptoms of this short and will cause no problems other than the battery will eventually go dead.