I replaced my stator 3 yrs ago (along with a MOSPHET regulator).
I've now just replaced this one ! All 3 phases shorted to ground and winding ties (a type of cord or string) that secure the 3 output leads), burnt to a crisp and in pieces. This is stator #6
I've been "smashing eggs" the past two weeks trying to understand why my stators are baking like 'tators in the Kawasaki Easy Bake Oven. I've come to some conclusions.
* The only notable auxiliary load on my electrical system is 55W driving light. Instrument cluster lighting is all LED as are my two front signals, brake and tail light.
It's my understanding that the '80B's and up had the alt. cover cast to supply an oil-spray to cool the stator. The '79 and '80A's did not have this oil spray feature. That's not to say there's no oil in the'79/ '80A covers. There is....and a lot more then one might suspect. The oil comes from the crankshaft end bearing. This oil is returned to the oil-pan through a port in the crankcase, adjacent to the bottom of the cover. I will further surmise that Kaw. made an effort (?) to cool the non-sprayed stators by utilizing air circulation within the cover. It was likely Kawasaki's assumption that the oil being discharged out of the end bearing plus some air movement would be adequate to cool the Stator. Clearly it's not. The subsequent change to an actual oil-jet spray substantiates this.
Note the two covers. '79/80A vs. the later oil-spray version.
The oil nozzle in the later versions can be seen in the inside of the stator pedestal. Note on the '79/80A, the "notch" in the pedestal. The "notch" is not present on the oil-spray version. I believe that this notch was intended to provide a path for air flow into the center of the stator where the spinning rotor centrifugally discharges this air within the cover. The rotor acts as a rudimentary squirrel cage fan. How much oil is scavenged and distributed along with this air is unknown but clearly not adequate to sufficiently cool the windings. The problem with this design is there is no replacement/supplemental air to aid in cooling. The air within the cover just gets hotter and hotter and eventually the insulative coating on the windings fails from heat break-down and that's the end of the stator.
For the past two weeks I've broken a few eggs trying to figure out how to get a continuous supply of cooler air into my cover. So far without success.
I suspect that there are more stator failures on the '79/'80'S being blamed on the OEM voltage regulators, then may be fair. Always a controversial topic: Which failed first? Did the V/R fail and take out the stator of did the stator fail and take out the V/R?
My personal opinion based on my somewhat extensive experience and continued bad luck is the '79/'80A Stators fail first, in most cases.
I'm now approaching the "cooling" issue from another angle and if I find what I believe to be a viable solution, I'll come back to the topic.