It has to do with a bearing lubrication issue. I don’t know if it’s due to the heat generated or the rpm’s, but the only lubrication is via the fuel/oil mixture. I run two temp sensors, one for the water and one for the main bearing temp. During a long WOT run, you can see the bearing temp climb and as soon as you lift and the rpm’s fall, so does the bearing temp. When geared correctly, it’s never been an issue for me on a purpose built kart track…..but they do warn it could be a potential issue in a road course.
