I just bought a 08 450x and have the same problem with my front forks.I have done a bit of riding on and off road with it.
Before i bought the bike it sat for 3 years and had very few miles on it.My front end started feeling strange so I elevated the bike so that both wheels where off the ground and found that I have play in fron and rear suspension.
Do the forks need a complete rebuild?or is there a way to get the play out via adjustment?