Clutch Main Spring.

Regardless how it’s knocked out, I’m not comfortable with the cross type hit the bearings gets in this process. The balls can get deformed from this type blow.

What makes this method of removal so attractive is a hammer smack is used instead of pulling the engine off the bike and completely disassembling it, splitting the cases.
Even the nylon hammer will cause potential bearing deformation. The issue isn't usually the ball bearings that get deformed but the cage they ride in. Plastic deadblow hammers are the most ideal style to use as the force they exert is more of a shove than a punch so they tend to be a little kinder to bearings. I would personally just put new bearings in anyway as I did the repair but I know not everybody is as willing to spend the few bucks as I am.