*Update Jan 9, 2015
New filament guide works at faster speeds (tested at 30mm/s) and seems to work alright. I would still recommend 20mm/s, at hotter temperatures than they recommend.
Place filament guide as pictured above, so it is touching (or almost touching) the G2 pulley.
First attempt at making Printrbot filament guide for Ninjaflex.
Prevents filament from tangling up.... Tolerances need to be smaller.
Still requires very slow print speeds... like 10mm/s speeds for everything... at least that's what I've successfully printed at with it so far. 20mm/s seems too fast.
Print temp 240.