Occasinally, when I play with my YYF Proton, I hit it so something and the gap loosens. If I don’t stop the yoyo, it splits. Is this normal? How do I fix this. (BTW I bought my Proton used and don’t know much about it).
Add a bit of Teflon tape to the axle.
Yes, teflon tape or light duty loctite work fine. You can also tighten them a tad more. I’ve had a few that would spin apart on a hard throw as well until I gave them an extra twist (not too much though).
Blue loc tite is what I use. works like a charm and cheap as can be!