My friend has a speeder and wants to add a konkave bearing, but, no matter what he does he can’t get the old bearing off, any advice?
This can damage the bearing but you could use a pair of needle-nose pliers. Im not sure if i spelled that right but you get the idea. So basically just get a pair of pliers and tug at it, it should pop out rather easily with pliers. If that doesnt work, well im all out of ideas. Good luck! 
Actually, that doesnt damage the bearing, it only damages if you somehow scratch it. That is the correct thing to do. YYJ’s are made so the bearing doesnt come off easily, so just do that to get it off. Thats what I do.
i usually use a par of round tip bar-b-q tongs. but at the moment i cant get my bearing of my sunset for some reason. later an remember keep it spinning.
I had the same problem when I helped my friend take his bearing out of this darkmagic. We finally got it out with a pair on needle-nose. But when it came out the shield came off too. Idk y. So ya i would say just us a pair of needle-nose but be careful…you dont want to damage anything or anything.
http://www.yoyoguy.com/PN/YT04/Yo-yo-Tools/Pog-and-Bearing-&-Jam-Tool
very effective.
Pliers can damage/break the bearings if you not careful.