i have an 04 400ex. it was running fine until i had a party at my house. everybody was riding it and it was going fine. then after wards, i stoped the machine and couldn't get it started again. i towed it home and jumped it. i just got a new battery so i knew it couldn't have been dead. then after i jump started it, it was running fine. then a week later i went to go start it and it just kept rolling over.