What would be the correct value for choke? I already tried a 200V electrolytic capacitor without choke, and it got hot within 1 minute
Ah, well that is a good question! But not a simple one.
I think you need a choke, an inductance, rated for a bit more current than your motor draws, in one of the wires to the motor, plus a mains-rated film capacitor across the motor. The cap should be rated to something like 630 VAC, and will only be maybe 0.1 uF. Not expensive stuff. An alternative would be to buy an IEC filtered mains socket, but then you would need an IEC plug as well. Not a silly idea, mind. You would (have to) earth the earth pin on the socket.
The 200 V cap was simply the wrong thing to try. It sounds right, but it could not handle the RF spikes.
A caution: do not try using an 'ordinary' capacitor. It would probably fail fairly soon. By the sounds of things, this is a harsh environment!
Now, this is quite different from putting in a large filter capacitor. But try it and see how it goes. If you need to add a large electrolytic filter cap as well, you will probably need a rating of about 400 VDC at least.
I doubt you need a bleed resistor across the 0.1 uF capacitor: it's very small, but it won't hurt.
Cheers