The LM8UU bearings they stick in these MPs are complete garbage. I think instead of balls they just crammed the things full of sand. That's what it felt like, anyways. These new bushings are buttery smooth when properly lubricated. I used some 7000 cSt RC diff oil and slathered the rods up good, now my Y wobble problem is dealt with.
Monoprice Maker Select V2
Came off the printer good in terms of OD, but the ID was too tight, so I used a drill to open em up a little. A 21/64 bit is a little over 8mm, but with the flex of the plastic, it cut away just enough material for a good fit.