I've heard about this in the past- 250r owners should change the metal washer on the drain plug with every oil change. Well my buddy just noticed that he has a hairline crack on the case threads on the drain plug, apparently from not replacing the metal washer when doing oiling changes. I guess the metal washer is meant to collapse a little when the drain plug is tightened, so stress isn't put on the female threads. Just a warning to 250r owners to replace those washers when doing oil changes.