I have just bought a beautiful Silver VFR 750 F 1997 model with 29k on the odo. She runs very smoothly but a very audible knock is transmitted from around the cams when she is warm on idle only. It comes and goes. Does anyone have any comment to set my heart at ease about this. I do believe these to be the most reliable engines of all Jap bikes so I´m a little preturbed by this. Kind regards in advance