We just bought a 400ex for 1800. It is a 2002 and it looked like it was in very good condition. My dad test rode it and he said that he was feeling jerkiness in the chain. We bought it and took it home. We rode it around and it started to make noises and the axle wouldn’t move. We rolled it back and fourth and the axle would free up. It is now setting in the garage. Any help?