MB 2x, ninja flex, and general extrusion issues

hi guys, i have a makerbot 2x and a folgertech prusa and, quite honestly, the makerbot's been constantly giving me issues. Very rarely will the 2x give me a problem free print.

I usually print ABS with it at 0.1, sometimes 0.2mm layer height. I use stock heat and speed settings (230 nozzle, 100-110 bed), and releveled my plate numerous times. The 2x will usually print fine until it gets to a certain height, then it will start showing signs of extrusion issues, then stops extruding altogether. I haven't checked if it occurs at the same height every time, but it consistently fails my prints in this same pattern.

I decided to give it another go yesterday, after weeks of not using it. I was making rubber tires for a toy car, so i loaded ninjaflex. I edited my heat and speed to match the suggested settings on the ninjaflex website. Once again, the print failed in the same pattern as my ABS prints.

Pictured below is the makerbot printed wheels next to the same wheels printed on my prusa using the same settings.
http://i65.tinypic.com/2wlzkus.jpg

I can't figure this out. The best i can guess is that it has something to do with the nozzle getting father away from the headed bed? (which was only set to 50c for the ninjaflex, so it's not like it was an intense heat). The prints are actually pretty clean up to the point where they start failing.

Any suggestions?

EDIT: the picture appears normal on my computer, but upside down on the phone, not sure why.

which extruder are you using on the mb ?

I had a similiar issue with my right extruder and eventually just gave up (fortunately have another dual extruder machine where both work equally well) and just removed the nozzle and now use it solely for single extrusion prints. Left extruder has never given me any problems with anything.

Basically try the other extruder and see if the issue persists.

i use the right one almost exclusively. I can't recall if the left one did it, but i'll certainly try it when i get home.

Even if the left works, i'd like to figure out what's wrong with the right one. I mean, there has to be a reason behind that failure pattern, right?

yeah, I reckon it's a heat issue. After a certain period of time something gets hot and stops working properly.
Could be loose wire, dodgy motor - lots of things to check. I just couldn't be bothered :-)