Sanduhr

Hi guy's, Im new at this forum weile ive received a suzuki gsx1100e from a friend of mine. He had problems wih the dynamo falling of the shaft and therefor pushed it in their garage for 15 jears. Now Im dismantling it to check te status and the firt this i found is the chamshaft is damaged and the bearing toplayer is ruined. Is ths happened before and does this mean i need a new cilinder (head) Thanks