title_body: How hot is too hot when it comes to multirotor motors?
upvoted_answer: Temperature is a killer of motors over time. If motors are exposed to prolonged heat, the magnets in the rotor lose their magnetic field strength over time and consequently reduce the lifespan of the motor.
  
  Generally, a well-tuned drone should not have extremely hot motors after flying (with a few exceptions). It depends on the motor, but you should avoid raising the motor’s temperature past 170°F; any hotter, and you run the risk of damaging the rotor’s magnets and decreasing performance and longevity. 
  
  https://dronenodes.com/drone-motors-brushless-guide/
  
  https://www.rcgroups.com/forums/showthread.php?1329288-Normal-brushless-motor-temperature-range