I am trying to help out a neighbor kid that stripped out the oil plug on his quad. I tried to tap out the hole with larger threads but the tap hit something. I looked up the hole and there is a flat head plug?? threaded about an inch up. I unscrewed it and have no Idea what the purpose is. I can't find it on the online scamatics. any Idea's. Can I drill out the drain hole to 9/16 and retap ?? or any other thoughts that could save a 16 year old some $$$$$

 

Buy a tap with a flat end. Or thread a nut on the tap and grind it down. Then unscrew the nut and that should fix the burred threads on the tap.