When I first got the Grid II the extruder platform traveled about a 1/2 inch too far to the left which made the x axis belt skip. After several hours of trying to get it to stop doing that by changing the home offset position for the x axis I now have a very loose x axis belt which now skips out of sync with the print at random occasions. So basically unless there’s a way to tighten the belt or find a source for a new one I have a $1500 paper weight sitting here.
I had the out of sync because of the dual head sometimes hitting the printed object. Therefor I 've Switch to the single Extruder. I think many People will anyway not be able to use the two Filaments.
Normally, you can take the Extruder apart and shorten the belt by reducing the number of used belt teeth.
in order to tighten the X belt ,loose the 4 screws fix the X motor then adjust it to tighten the belt .then fix the screws