Trilby

i have the exact same problem, you desribed it perfect....like metal hitting something. My 2001 SR has only just done 5000 Miles....i thought it was the tappets so i sorted them, then i put it down to maybe the cam chain but that and the timing in general are all fine....then next the mixture in the carb....this does seem to sort it out but it seems to somehow reset itself after an hour or so. I think im just gonna get a new carb and see if it does it again. It is a very intemitent noise and it only seems to occur on tick-over. and when the bike has warmed up it seems not to happen as often....can anyone help?