This is a little fixture which clips onto the top of the SD2 frame, and holds a smooth 7.3 mm diameter rod just inside and above the Y-axis belt, keeping the wire bundle from hitting that belt when the extruder is on that side of the unit.

I made the "Solidoodle extruder head wire bundle guide" by robbruton (http://www.thingiverse.com/thing:51134), but couldn't get it to print as smoothly as I'd like, and within a couple of days I started seeing some of the black braid surrounding the wires rubbing off on the guide, so I just needed something smoother, and the aluminum rods fit the bill nicely.