I have yet to see the timing off on a vintage machine like a 401 unless Igor or Bubba have been working on it before I got it. Too often timing is blamed when other things are actually the culprit. I've also never seen a worn out motor on one. Ones that need to be serviced, but not worn out.
I also sew over pins all the time. Occasionally break a needle or bend a pin but I've never thrown off the timing in a vintage machine. I am careful however when I sew over pins with a newer machine, knowing that it could happen.
Cari