Mistery random layer shifting with PLA  

Mistery random layer shifting with PLA

Although prints are mostly ok, after upgrading the bearings to the Mini I am getting these ugly layers randomly in my prints. The quality print is also not as great as before even using the same settings. 

I just changed the bearings from X and Y axis to Mizumi ones using the super lube included. After that, just some cleaning. I printed a couple of different pieces and the ugly layers do not appear in the same height, so they are random and we might discard a mechanical issue. They show in both axis. 

Troubleshooting:

- I have tried both prusament and cheap filaments. They are somewhat dry and there is hardly any stringing. 

- Tweaked the belts tension, should be as before. I had overtightened them and now they should be fine

- Tightened both motor´s gear screw, made sure they are aligned

- Squared the printer

Do you have any ideas of why can these layers appear? 

Thanks everyone.