Here's a typical BSA unit twin including the gear cluster, takes 3-4 hours of do-it- yourself work.

  Now, after ELEVEN years of Vapor-blasting by Bikesalotsm...in all these years "not one single part has ever been lost in shipping!"

   
This Norton International has a magnesium bevel box and covers.
Here's a nice BSA unit single. Couple of hours.

  Ducati twins are massive!  And they take longer.
BSA semi-unit twin
Do you think this BMW can be saved by vaporblasting?
Of course it can.