Can you clarify that temperature drop Kawboy? Perhaps in Celsius? My rough calculations are telling me that's at least 20 C in the engine oil temperature? That would be a lot and just because of using a different regulator? That seems way better than having a triple size radiator, if even possible. And perhaps not desired. The engine would never warm up in winter.
The stock regulator and some of the aftermarket regulators are shunt regulators. They operate the alternator at full output all the time. by regulating how much voltage goes to the operating circuit and how nuch gets "shunted to ground". The stator will be operating at max output causing the windings to generate a lot of heat. The engine oil keeps the windings cool by absorbing that heat which obviously causes extra heat in the oil.
The latest version regulator/rectifier from Shindengen is a series reg/rect. which switches the output on and off as required to maintain the output voltage so depending on how much load is on the electrical circuit, the alternator will be running at lower output and generating less heat.
One of the other motorcycle sites I happened across had done some studies with the new SH847 Shindengen reg/rect and found that as a result one of the benefits was a reduced engine oil operating temperature and they had measured as much as 30 deg F (which is 16.6 deg C.)
Wow! That is an awesome advantage, well worth having. My KZ1000P suffers here as well( Just swopped out a very burnt-out looking stator a month ago)... I might buy a Shingdengen for that too, see how that pans out, and then put one on the KZ1300 as well when I'm there.
I was planning to run waterless coolant through the system anyway to keep the temperatures down, as that has far better cooling capacity than water plus additives, and doesn't need to be changed, ever, but this is an added benefit to be gained if starting from scratch. I shall sure look into that when I get to putting the electrics together.... which looks to be soon as I have struck a deal on the forks and once I have found a pipe bender to form the rear hoop, I'll be concentrating on electrics and cooling.
So I now need a radiator and fan. I read there are two types, four blades and six blades. Are these both stock? Are the radiators different from model to model or will one from any model fit mine (a 1979 KZq300 A1)?