Originally posted by jwwu
I've been overgearing my stock motor considerably... it gets ridiculously hot after a run... and I noticed that the comm winds are darkened. Is the motor cooked? And if so, what's the effect of a cooked motor? it seems to run fine...
If the windings are darkened, throw it away. The motor will still work, but not to the performance as it would be if it were properly maintained, and geared.