I have a 2000 r6 and when it reaches around 120 degrees i can hear this loud knocking sound. I'm pretty sure its coming from inside the engine casing. When the temperature warms up to around 175 degrees, the knocking sound stops. I 'm not too worried about it but it just gets annoying sometimes when waiting at a stop light and theres an ugly knocking sound coming from your bike. Any one know what the problem could be?