Using 1.75mm Filament on Ultimaker 2

The guide below is for the Ultimaker 2 (old version) extruders. NOT for our Ultimaker 2+ extruders, unless modified to clamp down further.
YES, it IS possible, but PLEASE read the following guide first and follow the steps rigorously.

https://learn.adafruit.com/using-1-dot-75mm-filament-on-ultimaker-2?view=all

They also provide a nice printable PDF for download which is handy to have at your side.