TOPIC:

Checked for continuity between the phases and two are shorting to earth. I guess that's why the previous owner took the bike off the road due to charging problems. Anyway, crankcase covers will be off to the chromers shortly whilst I get on with painting the engine. I'll be using this stuff as it appears to be the closest match [attachment=

SP995

ENGINE ENAMEL

CAST ALUMINUM

Good to see you have that sorted at least. Such a common problem. It wouldn't hurt to do a little investigating to see if you can see any obvious faults like bad wiring etc. They can definitely burn up on their own over time, especially crappy aftermarket ones but it would be good to rule out anything else. Test all the components using the manuals test procedure once you get it together, just to be sure.

The epoxy windings coating was overheated by the engine oil. Common occurrence, as there is no full pressure oil movement in the covers, only hot oil mist and drain off.

I'm inclined to believe the contact in the voltage regulator are fused closed, causing full output of the alternator to the circuit. as the full output is not being turned on and off, the windings will be fully energized and that will cause overheating of the windings and burn the insulation on the windings to a crisp.
My personal preference is a MOSFET based regulator similar to the one Scotch just finished installing. The MOSFET based regs have a higher capacity for ampereage and don't fry and get stuck closed.
You need to ensure the reg is satisfactory before "just replacing" the stator. Preferably, spend the 130 bucks and get the MOSFET reg and don't look back.

I don't remember the 1300 regulators being of a point design, only solid state. This would ramp up the system on start up, and when charge voltage got to the limit point, excess charge voltage was dropped to engine ground, so as not to over charge. I have seen them fail and not charge adequately, not enough bolts, but, never seen one go above drop out volts.

With no points, no contacts inside them, only solid state components, so, how does the regulator fuse closed a contact it doesn't have inside it?

Last Kawasaki street bike I saw with a contacts type regulator was the 1969 thru 1972 H1 500 triples, those systems turned the rotor on and off to regulate charge voltage, and then, they went solid state regulator and permanent magnet rotor system after that. Rotors in 1300 are permanent magnet, aren't turned on and off to regulate charge

The "diodes" that are used for switching the current to ground on and off are either thyristors, basically a diode with a third leg that acts as a switch, or MOSFETS, which are transistors functioning in a similar capacity. (and transistors are made up out of diodes in their most basic form)

Regardless of what type of "switch" you use, the act of switching it on or off casues large amounts of heat, and when fully on, shorting things to ground, that causes even more heat... That heat is usually much, much more than what the Rectifier produces... But both parts are equally affected by the heat...
What does heat do to the components?

The heat makes diodes of all types age faster, and if you have enough heat, the diode starts to change characteristics, making it less exact...

The loss of precision creates wilder swings between high voltage and low voltage, making the Regulator have to work harder to maintain the output voltage where it's supposed to be... And the harder it works, the more heat it produces, and then it looses even more precision... That creates a pretty steep downwards cycle...

The result of the ageing is obvious, first it becomes even less exact... Then it fails, when it cant keep up... And a diode can fail in two ways...

One, it can act as a fuse and stop conducting... The result of that is that the R/R produces lower voltage than specified and cant keep the battery fully charged... That slowly kills the battery, but the bike keeps working a good while before you notice anything...

Two, it fails by conducting both ways, or in the case of the switching diodes (thyristors) "leaking" when it's supposed to be shut off... That makes the R/R produce wildly varying voltage, lower or higher depending on what combination of diodes are currently conducting, something that again makes the R/R work harder... This results in the battery being overcharged, the bike doing "weird things", like popping fuses or randomly dying...

And eventually, the diode or thyristor short circuits, conducting both ways, or becoming unable to turn off... The result of that is a boiled over battery, smoldering electronics and a big hefty bill for repairing your bike...

But there are other things creating heat... One is corrosion on terminals in the wiring harness... It's bad in all places, but more catastrophic in the connector for the R/R, since it's already hot there... Soldering the terminals instead of crimping them makes it easier to keep them free of corrosion... Making sure that there is no way for moisture to get in there is another good tip...
What is the difference between a thyristor and a MOSFET based R/R?

The switches in the Regulator part are either type, but they both do the same thing... The rapidly turn on and off, shortcircuiting power to ground to keep voltage constant... That's called "Shunting", and almost every type of bike R/R used now is made this way...

Every time you short circuit something, it creates heat, just from the short circuit... That's the same for both types... But, the difference is in how you switch!

On a thyristor based R/R the most heat isn't from the shortcircuit, it's from the switching... A thyristor is basically a diode with a separate leg, acting as a switch... But the switch has a delay... The thyristor relies on the current flowing through it, to keep it open...

Basically the switch opens the door a crack, and then waits for the current to crash into the door, slamming it open... Closing it is similar... You slowly, slowly push the door closed enough until the current looses power and cant hold the door open, slamming it shut...

As a result, the thyristor is horribly inexact and inefficient... It takes time to switch, and it creates huge amounts of heat while doing it...

The MOSFET is a bit more intelligent... It doesn't rely on the current for opening the door, and it doesn't try to close it slowly... Instead the switch is really a switch... Switching it on means it starts to conduct fast, and switching it off means it stops almost as fast... That creates a lot less heat, and makes it more exact... A lot more exact...