Gearing--
Early in the morning your motor will run cooler then as the track warms up. Also as the traction gets better the motor will work harder.
I temp my motors on the can just below the endbell. Temps should stay below the 170-180 range. You can actually undergear a motor and have it overheat as well. There is usually a 2-3 tooth "sweet spot"
Scott runs a T4. He should be able to help confirm what Mitch said about gearing.
