I put a new Dura Ace crank on my SL2 when I built it and I can't believe how much noise the chain makes on the chainrings. When the chain line is near perfectly straight for the ring I'm on it is very quiet but if I shift up or down more than a cog or two in the back I can really hear the chain on the rings. I've got just over a hundred miles on the bike and just gave the front der a tweak because it had shifted some but otherwise my drivetrain alignment appears good. I'm running a SRAM 1090R chain but if this continues I think I'll pick up the Shimano CN-7801 and see if that's more quiet.
So, is there a break in period for cranks? I'm wondering if there isn't just a bit of an edge to the chainring teeth that will be smoothed down. Let me know what you think.