[Purdy Swoft]

I've had that problem and posted here about it, you will have to go back a long ways to find the thread . The problem was ill made parts . Remove the pulley and take a close look at the back side of the pulley . There should be a mark on the pulley or the front motor mount yoke where the pulley was striking the yoke . My fix was to grind just enough material off
the pulley or yoke to solve the problem. Usually not much material will need to be removed . A little bit of spray can black paint will hide the fix . This worked for me every time . A lot of the reproduction parts need a little bit of fitting , one way or another .