Originally Posted by
sclogger
Although to firm up some of the comments from above, on my first build I had no issues with my motor mount. On my second build I had to grind down the side facing the motor that the bracket slides into. It seems it was machined about a few thousands too big and hits the motor as you trying to set gear mesh.
I had this issue but it was actually caused by the screws that hold the front face of my castle motor on to the main body. The screws protruded out of their recess by about 1/32" and were making contact with the motor mount when I tried to slide it in. Backed each screw out a bit and hit the head with a grinder to shorten them up a bit and then it slid in fine.
Pretty weak on castle's part if you ask me.