It was mentioned in the original posting that the Duo-Art motor that
was running hot had been rewound.  If that is the case, there is either
a problem with the rewinding job, or the motor is overloaded, possibly
by improper spill-valve setting or use of the wrong pulley.

If the motor was not rewound but merely "reconditioned" who knows what
they might have done.  There could be electrical leakage due to
insulation breakdown.  This might have been exacerbated by cleaning
with solvents.  If there is any chance of this, the insulation should
be tested with a megger or a modern insulation tester.  Either one will
test resistance of the path between the electrical connection and the
case of the motor, at high voltage.  If it is not in the high megohms
range, there is a problem.  If nothing else, this can cause a serious
shock when you touch the motor case.  This can also be the case with
the old rubber insulated wire used in the original conduits.  I always
check the insulation with a megger and replace the wiring if it is bad
and rewind the motor if the insulation in it is bad.

Spencer Chase