this modification will increase the print height from 100mm to 160mm (3.9in to 6.29in). this was achieved with no additional hardware, just printing new parts. the ao-101 use 30 degree angled parts for the upper frame, i changed everything to 35 degrees to allow the carriage to travel higher.
parts and sketchup file can be found on thingiverse
you will need to reflash your firmware with the new Z_MAX_POS value to allow the printer to reach that height. you can find detailed instructions on how to do that here https://www.lulzbot.com/?q=support/re-flashing-your-3d-printers-firmware
on about line 200 of Configuration.h change
#define Z_MAX_POS 100
#define Z_MAX_POS 160
and thats its, you’ll now have over 6 inches of print height!