I have a yoyojam dark magic yoyo and i heard people talking about the konkave bearing. What is so great about it compared to the bearing that came with my dark magic? can i get longer sleep times?
I put one in mine and didn’t notice an incredible change it’s still quite responsive too.
no, they don’t really do much. Just work on your throw 
They do a nice job of keeping the string fairly centered, but nothing a good throw can’t do.
I thought KKs ship lubed… Try cleaning it or letting it break in. Also make sure you don’t screw the DM all the way in as it has an Adjustable gap.
The point of a KK in a DM would be to help keep the string away from the Oring and the starburst more. You don’t really need it as shown by Operation Dark Magic, and Andre Boulay in general, but if you already have one it’s a good tool to help spin times for learning and such.
On another note:
I usually hear that KKs kill suicides too, and can cause snagging, if you still need a good string centering bearing, I’d recommend the Terrapin X, Their bearings by themselves are amazing, but the centering is a nice plus, but it doesn’t force the string to center, just suggests.(mine always is centered when I look at it.)
Of course Apetrunk is also(or always)right.