Source of the engine ‘Clacking’?

I'm pretty sure the source of the clacking noise has been identified!

The shell bearing on piston 2’s conrod is scored and showing significant wear compared to the other conrods…. 0.4mm difference across both shells vs the other conrods!!! 

Plenty of room for movement and so noise. The shell and conrod oil pathways/holes are all blocked solid (melted metal?)….so I suspect it was running dry before then the wear filled the oil holes?

The scorings is also on the crank but no measured difference….hopefully this can be saved? The oil feed in the crank are clear in all cases here though! 

Stripped all components down and wiped clean. I'll box it all up and take it off to Swiftune to check the crank work, when we take the block and head over for reworking.