Y axis problems

Hello,

I've been having a problem with my Y axis hanging up I think. I wanted to confirm my findings with someone who has a little more experience than I do. When I've printed larger Items like the one in this photo:



you can see that the motor seems to stick and then the print offsets. It feels like this pulley is the cause of my problems:


Pulley video

Does anyone have any recomendations of a better pulley that I could use or how can I fix this?

Thanks,

Loren

hello
I'll throw out that pulley cover and just use the 608 bears, on an prusa i3 dont they use 623? am wondering that because it looks like an i3 pulley system. " it maybe worth posting in the prusa i3 section, from the video those belt tensioner look like they get close to bearing idler, I move them under the bed when it centred. then I look at the motor pulley looking for a loose grub screw.