Engine light knock

[Worz]

After a lovely long dry summer I finally bit the bullet & took the lump out of my 12,000 mile fzs600, the local dealer and a number of mates were all flummoxed by the noise, so after checking all the usuals timing chain, valve caps etc I began stripping the engine, just hoping to find the source of the noise.
To my amazement once the barrel was off no3 big end was as loose as a dick in a bucket, somewhat relieved to have found the cause of the light knock, but very surprised to find on such a low mileage lump.
No other obvious signs of oil starve & no play or wear in any of the other journals.
Any thoughts ??.....…

[Gav]

Wow yeah not good for 12k.  However, great you found it and I know what it's like to that huge relief feeling.

[Dave48]

Either a breakdown in the pressurised oil supply or faulty/incorrect size big end bearing shell?
While engine stripped check entire oil supply system-strainer,pickup,oil pump,oil feed jets,pressure relief valve but I imagine faulty oil supply would affect more than one set of shells.
Re bearing shells-any clues from code numbers?- see relevant section in Haynes manual.- assuming engine has never been dismantled from new this points towards incorrect size/clearance from original assembly?

[Worz]

Cheers dave, will pay close attention to all that, does look like engine hasn't been stripped before, bores are like new and no oversize stamps on any shells text :-/
Thanks
Worz