That's right, we're talking about stock engines in general, since modifications like over-boring and racing pistons would naturally bring their own special considerations to the forefront.

 

I really only have substantial experience with car/truck engines, not so much with motorcycle engines. But I've never heard of breking-in ANYTHING by beating on it. Clutches, differentials, cams, brakes...they always call for a strict, gentile break-in procedure and I don't see how a motorcyle could be any different, but like I said, I'm not an expert.