I break an engine in how I plan to drive it.Dont have to worry about most cams now a days because they are rollers and dont need break in time and rings shouldnt take much to seat in as long as they are honed right.Arent most bike sleeves plated.I believe if the engine is going to break, its going to break if broken in easy or hard and I think if you build it right it wont break.I build lots of motors and non have broken from me beating the piss out of them.