Hi Adrian,
Thx for your reply. My english is not so good, when I said "pitted" it's no rust-pitting I mean, but clearly mechanical wear, like fretted through the hardened surface. I have the impression that the reason is a bad alignment (not square?) of the crankpin, as the wear apears only on one half of the circumference (the attached picture is the worst example, on the two other cranckshafts wear is just beginning). However, the outer races doesn't seem to be damaged...
Ludo