I've got an older replicator 2 and newer plastic from makerbot. After a while into the print the filament jams and the extruder starts making the knocking/clicking noise. I have measured the filament diameter, which is around 1.83mm (totaly not 1.77, makerbot store you lie). Almost all of the newer rolls we have are around 1.8-1.9. Changing the filament diameter helped but the extruder still jams part way through.
Also the prints have a gap at the start of each layer, creating a what looks like a seam up the side of the print ( which can be seen on the side of the thumb on the hand, and down the chest of the rabbits) I am hoping they are part of the same problum

19238627_1613066055384850_539080211_o.jpg 19549697_1613066058718183_15765521_o.jpg