I am working on a late 1950's Kenmore 158.371. The motor lets out a puff of smoke whenever I start sewing. I have not over-oiled it. I can't tell if it keeps smoking once up to speed because the air flow the motor produces at that speed blends the smoke into the flow to make it invisible. I would like to open up the motor to see if I can find anything wrong, but the motor name plate is riveted to both halves of the motor case across the seam of the case. I've seen other motors where the name plate was screwed on, or one side of the plate was slotted so the plate could be slipped off on the slotted side. Does anyone have experience with this? I can cut the rivet or pry the plate loose, but I don't want to damage anything if I don't have to. Also, any advise on the puff of smoke is appreciated. Thank you!

Victorian Sweat Shop is a great forum for finding very wise people who can answer nearly any question about vintage machines.
Lots of them came from this board
https://www.victoriansweatshop.com/?forum=511434

Welcome to the QuiltingBoard. If there's no slot on one end, I would use a dremel maybe to remove the rivet at just one end, then you can keep the plate on it. If you have a small enough screw you can use it in the rivet hole for the end you remove.

If you end up removing the entire plate, keep it in a small container of some kind with the machine, so you have the motor specs if you ever need them.

From your picture over on VSS it appears you're using a rubber stretchy belt. If so that type of belt can put a lot of extra tension on the motor shaft which can affect the motor's ability to spin up and to reach optimal RPMs. I would look for an appropriate sized cogged or v-belt.

Thanks for the tip. It had a more rigid belt on it, but it was crusty and I had a rubber belt, so I put it on.

I would also try vacuuming out the motor with a shop vac (before disassembly), from both ends, dust or debris could be igniting when the motor spins up. Vacuuming could possibly pull out any grease that may be in there, if the grease is hard enough.

Good idea, I'll try vacuuming and maybe compressed air. Thanks!