How do i lube my bearing on a shutter yoyo?
like any other yoyo. I would recommend taking out the bearing from the yoyo with a tool. if it has the bearing shields I usually take them out but you don’t have to. then apply a drop or two of really small quantities in either side of the bearing. is there an issue n why you specifically mentioned the shutter yoyo?
Be careful taking the bearing out. You could break the bearing and or yoyo when doing it incorrectly. My YYF tool didn’t fit right, and it ruined my shutter.
Um… May I ask what you did that ended up ruining the shutter? I’m not trying to sound rude, I’m just confused. 
My YYF tool was a little bit too big, so I had to hammer it into the bearing for it to be deep enough to work. After taking it out, the bearing would be stuck on the tool. The only way I could get it off was by hammering it, and that’s what broke the bearing. As for the yoyo being ruined, the bearing seat received a big scratch, and a little dent. Somehow the tool or bearing did it, I really don’t know. Now the bearing didn’t fit quite right, and the yoyo vibes ALOT. I guess it wasn’t just the YYF tool that broke everything. It was my stupid idea of using a hammer too 
Lol, hitting precision pieces of metal with other pieces of metal may have not been the way to go
Here’s a good place to look for solutions to numerous yoyo problems, including how to remove and lube bearings…
Useful modification & maintenance guides - Axles,Clean, repair, tune, fix yoyos