I would not lube a servo DC capstan motor. If it is noisy it may need rebuilt to abate the noise. My 2p. Unless it is obvious there is a felt (or similar) lube pad at the base of the capstan shaft, but I don't recall there being any instructions in the service manual for lubrication of any of the motors. Can you post an audio file of how it sounds when it spins up?
Thanks guys, it's not too bad really and hasn't gotten any worse since I bought I bought it. I haven't noticed a big difference noise-wise in upright vs. flat. I just thought maybe there was a lubrication procedure I wasn't aware of (the operation/maintenance manual doesn't mention anything but I haven't seen the hard-to-find jumbo true service manual). I also now realize the oil I mentioned is more appropriate for capstans with porous sinter bearings.
I just saw fgonza's pictorial on replacing the bearings. Doesn't seem as daunting as I would've feared. I'll try that when I get some downtime. As it is right now, it just a minor nuisance, the machine how low wow and flutter.