my friends shee had similar damage, not quite that severe though, he came back from a ride and said his bike was down on power, and then we couldnt quite get it to start...so we...herm....tried pull starting it with my trike a couple of times lol
found out later one of the carbs came loose and that side went lean as fuck and fried a piston, the piston started to break up and we did the rest trying to force that broken motor to start