You have initial failure and then you get collatteral damage. Post some pics of the carnage. General consensus here in U.S. is that it ends up being cheaper and better to get a new crank that's trued and welded. Unless you put a plug with a2 in nose on it in , it is impossible for the piston to hit the plug because of the dome .Don't know if big end failing would cause piston to fail,sounds fishy to me ,don't matter really , it's broke. Blew a Suzuki T-500 once that only top of piston was left, did piston fail causing pin to drop into transfer or did pin drop into port exploding piston? Don't know , didn't matter it was fucked .