The first time I came across these 3 phase A/C oil cooled shunt systems was in 1977 with the Suzuki GS series-stators were frying-if it opened just the stator went out- a short would take the stator regulator and sometimes the light blubs-Suzuki's answer was oil related-it seems if the oil was old dirty low or the wrong weight the stator would over heat-they claimed if 20/50w oil was used-these were air cooled engines-the thicker oil could not carry away the excess heat fast enough so use 10/40w CCI Suzuki's brand all year long and only use 20/50 if the bike burned oil in the summer months-this worked no more problems-and oil burning in the summer with Suzuki's CCI 10/40w was way down over any other oil
I run mobil 1 20/50, and I can tell you that there is some truth in what you stated about taking the heat away, however, many of the stator failures were from a short at the connection or a short between cross over connections, this isn't caused from poor heat conduction, the primary cause is insulation break down and expansion, both directly related to the shunt regulator. Every time the engine goes above 4000 RPM for a sustained 10 minutes or more the stator heats up due to maximum output, each time the engine is at idle for 5 minutes or more the stator cools down as the output is reduced to base load.
Giving this some thought, let us say that some Kawasaki dealer starts offering a optional series regulator for $200 more, part of that offer they include a 5 year warranty on the stator, provided only the accessory load circuit is never exceeded ( 5 amp fuse).
So the question asked is why spend $200 more , the salesman says something to the effect that the stator never exceeds 60% of maximum output, under normal conditions .
Why could they offer extended warranty? Simply put, the stator is guaranteed to run cooler, a fraction of heat cool cycles of the shunt regulator and not the extremes of heat cool temperatures. So for the price of 2 tanks of fuel you too could upgrade your system using a used Polaris regulator.
Caution, if your stator has already started to fail, chances are good that eventually it will take the Polaris regulator out with it unless you install a accurate voltage indicator like neat little voltmeter
, once it starts going, best to park the bike and replace the stator, a couple failures have been caused by the 3 phase socket where one connector failed, what resulted was the other two phases carried the full load, called a single phase condition, the regulator ( shunt or series) cannot handle 23 amp single phase, a early sign is being below 12.8 VDC at idle but at 14.0 at or above 6000 RPM.
I hope I have clarified some of the technical aspects of this thread.