Custom Built 3D Printer - Infill issues

[LazyDev]

I need help. my 3D printer can print the thin wall calibration test perfectly, but when met with a task for infill, it's another story. Have got any tips that might help? Everything is calibrated (Although I am having an issue with the extruder) 

Extruder: 

I've calibrated it so if I extrude 10mm of filament, it will extrude exactly 10 mm of filament (Tested with the filament going through the extruder). Also, when the printer speeds up the extruder starts to "Clunk". I'm using the J-head extruder 

 

Print speed at 30mm/s 

Initial layer hieght 0.2mm 
layer height 0.1mm 

PLA at 210.C 
Bed at 50.C

20% Density

I use Cura with RepRap

Their's a huge amount of wobble on the Z and Y axis, but this will not contribute to the infill issue (Just incase you see any lines not straight)

[mc141]

Tweetthis post barnacules nerdgasm he might know hes into that stuff

[LazyDev]

After alot of headaches (And probably grey hairs) I think I have found the problem. I'm now confident in saying, my J-head extruder is defective. I also found out my J-head extruder is not a "Genuine" part, but a replication of the real part.

 

I'm getting consistent blockages between the black part and the aluminium block. I drill the filament out and the nozzel is good to go and runs perfectly.. for 5-10 minutes.