:that is just a weak point in these cranks. There is not much material at that particular joint in the crank.
One of the reason I know that doing that machining to widen the stock rod journal is not a good idea. Any material you take away from the "meat" or "cheek" of a crankshaft in a critical area such as a rod journal you are only doing yourself harm. The issue is how the oil system works & harmonics with these crankshafts. Balanced right and even line honed properly with the adequate clearances made...the crankshaft is still going to have a good bit of harmonics being generated. The only safe way to somewhat eliminate these frequencies being produced is to infact run a harmonic style damper that does the job in a good enough manner where it allows the engine to stay together.
