Irun a 2005 gs 500 f and the bike makes the same noise .I am told that it is cam end play but is not harmful to the life of the motor.Ifound that if you keep the oil full with LUCAS oil additive ithink 20%of total oil level the noise is pretty much gone plus you protect the motor.The stock battery croaked at 428 kms .I now have 1200 kms .It is a fast and fun bike with some bling.