[Luke Pike]

It seems you're opening multiple references for each set or get. All you need to do is open one reference for each physical device and wire it to as many get/set vi's as you want. Also, you're opening the motors within the while loop, which will slow the loop a lot. Move the Open Motor vi's to the left of the while loop and wire them to the get/set vi's in the while loop.

Motors take -1 to 1 for values, with 0 being don't move. I think if you fix the multiple references and opening motors in the loop, it will work.