Ken, another thought is that looks to me like you maybe missing a few steps on that circle picture. Now most of us know by now that the circles on the X are hard to get tweaked in right but they would have a look of more an ellipse shape if it were pure backlash. The picture looks more like half of the circle is offset which to me is more a sign that it could be missing a step or two on the transition back across the arc. You may want to try and see if you could up the current a little on the trouble axis and try again.
Hope this is helpful
Mark and Trish

 

double check the pully tightness.....mine did that once, and i found out it was slipping. took out screw and made a little drill point dimple...and all was good. peace, randy.

 

I to have to agree with Randy on this one, after looking more at the ramp to the hump. I think this is more likely a loose pulley not belt backlash or missed steps.
Good eye Randy glad to see you back bro
Mark and Trish