Temperature of a brushed servo motor?

Just got the Z axis of Bridgett running with a permanent magnet brushed DC
servo motor and a Gecko G320. So far about 45 ipm on a -Z rapid (lifting the
table) without fiddling with the acceleration. A great improvement over the
stock 12 ipm and healthy increase over the 24 ipm I was getting with the
original stepper motor on a G210a.

Question is, how hot is it acceptable to run a brushed DC servo motor. I had
the gain and dampening cranked a little high and the motor got hot to the
touch on the outer case (I would guess it was 120 - 130 F). I will try it
tomorrow with more appropriate settings, but I am wondering how hot is it
normal to run a brushed DC motor. I am guessing that if you keep them at
room temperature you are not driving them as hard as they are designed.

Tim
[Denver, CO]