Make inspection on the lower engine rod and main bearing after one summer (80H) sence refresh and bearing looking strange dont know for what reason.

Bearing is clevite HN serie.

Anyone have idea on that bearing issue?

Do they all look the same? Or is it just 1 bearing? Looks more like contamination or a flaw in the part than any kind of wear I have run across.

that is from the assembler,,did not do a good job of cleaning before assembling the engine,,my blowgun never stops working apon assembly..may have had some junk still in the main and rod journals or on the surface of the bearings..

Yes they all look like this.

I have also fond some metal flake in the corner of head (in valve train) i think that can be come by the lifter wear.
The lifter was brand new but now they have some scratche and litle wear on them by the mouvement.

Evreting was new before this season, .030 overbore cylinder,piston, rod,cam,bearing,lifter,aluminum head and i canot see where this can be come from.

I have do all the work less the block machining and i have always take care of junk when assembling.

i see no evidance of metal or dirt on that bearing,i have seen that on bearings from a blown alcohol engine,it was caused by alcohol contamination in the oil.can you feel anything if you run your fingernail across the bearing?

i have never seen it on alchol engines but i have seen it on nitro engines..man i miss those days...

Looks to be either crap from oil passages or fuel got in oil and diluted...does not take that much to kill the oil...then the bearings..

This can be a water/meth contamination in oil,
I have run with a water/meth injection systeme at 9psi B&M 250 blower.
The spot look like little hole probably oxydation.

It does look like particle contamination. Hard enough, it looks like it's not scratching surface, but becoming embedded into bearing. What is the clearance between bearing and journal? Do the mains show same? What brand filter are you using?