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
How old is the Replicator 2? MakerBot released an upgraded extruder part which could help.
While printing and hearing the clicking noise, try pulling the extruder lever up a little - if this causes thicker extrusion without clicks, you need to beef up the extruder.
have you tried good quality non MakerBot filament? Innofil, Colorfabb, Faberdashery are great. 1.8+ is awful tolerance- how did you measure? If it is outside spec can you you return for a refund?
Not knowing any of your settings I would say slow down and check the temps.
Where exactly does the jam occur? If it is up high in the barrel then you may be getting some heat creep. This could be from aggressive retractions on small areas with higher temps.
