Interesting topic to discuss and share experiences!
I have checked my bike's oil temp in the oil tank with a dipstick with thermometer. The red area starts at 120C (248F)
Below interesting links that supports the thought about minimum temp of 100C.
https://www.velox-motorsports.com/single-post/2016/07/10/Oil-Cooling-A-Deeper-Lookhttp://www.calverst.com/technical-info/lubrication-temperature-critical/Car or Motorcycle engines should not differ since its the oil that suffer of higher temps, right?
So what temperature can you run in your car/engine?
That is quite a loaded question and near impossible to answer without a lot of testing. We can give it our best shot, though. Most passenger cars are perfectly fine with oil temps up to 240-260 degrees F *utilizing the OEM recommended oil weight*, with some being designed to handle temps up to 315 Degrees F and higher!Optimum performance, for both economy and power, is achieved at temperatures around 100-107 degrees C (210-225 degrees F). Up to 120 degrees C (250 degrees F) is OK if a decent oil is used, but getting a little warm. I do not need to connect an oil cooler. Max temp I have seen now with the billet block with no air vents between 1-2, 3-4 is 110C (230F). Mostly around 105C (221F).
If living more south riding longer periods in ambient temp of closer to 30C (86F) I guess the temp should be around 120C (248F).
I did not have a temp gauge back in the 80's when I had a toring down to Jugoslavia with my RC 836 with CR 10.5:1. I remember taht I could not keep my boots against the engine, very hot. Amb temp was around 27-32C.
But riding the bike in southern USA amb temp between 30-40C or more, traffic jam that must crank up the engine/oil temperature!
Fairing that block the air cooling the engine can not be good either in a very hot summer.