Ok I found a 2005 yz450f with a blown motor for a pretty good price. I havent seen the bike, but ive been researching for reasons why this would happen. I found many problems with the cam chain, but that shouldnt lock the motor up. All he said was " I was ripping down this road and it just locked up and slid to a stop. And that there is a crack on the engine mount." So whats some of the reasons why the yzf450 likes to seize? I havent really found any anwsers. Thanks, Im just trying to know what to look for when I look at the bike.