As most have weighted in...40Wt is not heavy enough film for an air & oil cooled engine, once it achieves normal operating temperature rises to normal 200 deg C plus for the oil (and yes who says every day will be cool...even in winter, especially here in SoCal...got up to mid 70's on the coast, but in the 80's and above inland...personally do not ride only in one area...hope you don't either?