Why does the VPI motor thump

Why is it when I turn off my VPI motor I hear a thump through the loudspeakers? The only direct connection to the stereo is the belt.
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You're so right Liz. I just tossed my turntable in the trash.
I asked my local VPI dealer once why VPI does not install the bigger cap right from the beginning so we can avoid this problem. I was told that the big cap does not totally prevent the problem either as some systems will have the same problem with bigger cap rather than the smaller cap ( I don't know if this is really true but it is what I was told anyhow) so it seems like there are 2 versions of the cap and VPI installed the one that should work with the majority of the system (80% per VPI)as standard. If this is the case, I don't see that it is any different than certain preamp that needs to be turned on before power amp otherwise you can get a big thump as well if you turn it on after turning on power amp and I would not think that that preamp is crap either!
Ok ... I pulled my VPI Classic out of the trash and against my better judgment turned on the TT with the rig set at full volume -- no mute -- to see if there was a thump on turn-on. No thump. Oh well ... guess I'll keep this pile of junk for a little while longer. I know it plays great music, but I can let thump-free great performance get in the way of the "unfav" comments above. :)
Correction: double checked thump on turn ON. No thump. However, slight pop on turn off, but not a thump.

But really. Who cares? The TT runs dead quiet as best I can tell and my Lyra Kleos tracks beautifully on the Classic 3 arm. Sorry guys, I think this is a lot of nitpicking.