Thanks for the tips guys! The belts do have some slack in them.

The y-belt hasn't been adjusted since the belt guide (http://www.thingiverse.com/thing:359773) I was using cracked. Do you guys use a belt guide or is it excessive?

Also, I noticed that the bed leveling screws toward the back are tightened to the point that they don't clear the slots on the back of the frame. I plan to fix that soon.