My motorcycle recently required a new stator (plus a new regulator rectifier and battery) because the stator burnt out and fried everything.
What are the typical causes of a burnt-out stator?
2012 Kawasaki Ninja EX650
I think it is more likely that a fault in the rectifier would have the caused the overload of the stator. A bad connection is unlikely to have caused the problem, however a short circuit could have caused it, but that would more likely have blown a fuse first. Extra load on the electrical circuit could have damaged the rectifier and then the stator, especially if they were bypassing a fuse, however heated grips and brake lamps don't sound like they would cause too much extra load.
A Bad Diode in Your Rectifier Can Allow AC Current into Your System
A bad diode in a rectifier will dump AC current into a system. The AC current heats up the stator and the heat destroys the insulation and ultimately carbonizes it turning it into a low resistance brick. Most stators are three phase AC systems so there will be three diodes in the rectifier that can potentially fail and allow AC current into the system.
As well, the additional heat destroys the insulation on the leads in the wiring harness that can cause a cascade failure of the harness due to heat degrading insulation.
Here is a link regarding testing of rectifiers and stators.
The faulty diodes in the system could cause such ap problem , but there is ap small problem we always miss out , and that is the starter motor relay. Some times the relay fails to switch off after ignition and stays connected , the starter motor gets really hot just within 30 seconds . This heat eventually damages the whole electrical system ! Since the old starter motor also failed , i suggest you are better off replacing the relay ! Its very cheap ! Dont bother testing your old relay !
