I recently purchased a 2014 KLR 650. I was tightening the oil drain bolt, aftermarket Tusk magnetic bolt, to 21 ft-lbs when the bolt fractured in multiple places at the head. The threads don't appear to be stripped, and there aren't any cracks in the crankcase. I looked up into the the drain bolt hole and noticed that the threads have a downward v-shaped tapered opening to them near the top when looking up and to the bike's right side. Is this how the threads are manufactured? Is it for oil flow when draining, or could I have broken a piece of the upper threads? Any knowledge would help to calm some fears.