Latest data showed that non-repeatability was worse with higher amplitudes with cold oil, compared to normal DTE light turbine oil at 115 degree F. design temperature. Motor base vibration was over ½ amplitude at bearings in horizontal direction. As rotor vibration was much worse near the coupling end bearing, with a non-symmetrical orbit, bearing was taken apart and re-assembled. As impact tests on casing during coastdown at slow roll speed showed frequency near 1950 cpm, giving only about 10% margin, motor supports were also stiffened in the horizontal direction - insuring that the rotor/bearing first critical speed remained above operating speed. After re-installing bearing, and checking for soft foot after welding support braces, motor then ran with much lower vibration levels.