Have 2000 Hayabusa bought one year ago in perfect condition with 12500 miles on the clock. Have done 10000 miles in the last year even with 6 months spent in my bedroom (ground floor) during the winter. Over the last 3000 miles the engine has developed a noise and a knocking especially after a long run. It's not there when the engine is cold and not there when engine is warmed up but not ridden. Not really noticable when riding although it's hard to tell because of the can (Yoshimura). Most noticable after a good run when you are stationary and give the engine a little rev.As the revs are falling you hear this sound that's somewhere between a clack, clack, clack and a GRRRRR and feel a knocking through the engine. I've been told it's not rattly enough to be cam chain noise, but also that big end shell bearings seldom go on these engines, especially if they haven't been thrashed and the oil is changed regularly. I think I may have been riding with an overtightened chain for a couple of thousand miles, in fact, the noise began not long after the new chain was fitted. (Coincidence ?) Could it be clutch (no real difference in noise with clutch in or out)? Or maybe main sprocket drive shaft bearing (but noise Â and knocking happens when stationary). Anybody any ideas ?