I have never spun a bearing before*knock on wood* but hear people talk about it all the time. incase if I do in the future what kind of prolems should I look for, or noise to listen to?

 

Listen for a knocking noise because your bearings develop an egg shape if you spin a bearing and its the sound of your pistons/bearings going back and forth hitting your crank, if it is a semi quiet ticking noise than its most likely lash and youll need a valve adjustment