FYI Some might find this useful, it was taken from an older Rotax manual for their four stroke single cylinder air cooled engines, used in flat track, road race, off-road and street applications. It may have been updated since then, and those engines did not use an oil cooler, but I think the numbers are still accurate. All temps are in Fahrenheit
195 to 230 - Normal operating temperature
230 to 265 - Hot
265 to 300 - Overheating