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From what I can see in the pics. the wrist pin looks just a little scared (scratches), most likely from the piston heat transferring into the rod and affecting the lubrication abilities.
Just keep in mind when doing anything, like Vegas remarked, higher altitudes = less air, and less air = burning rich (fat). The reverse is as well true, lower altitudes = more air, and more air = burning (Lean)!
The piston in the pics. doesn't look too bad, as far as burning mix. But remember, this is "not" a race engine, you don't want it to burn too awfully hot & clean. Personally I would like to see mine looking a little darker (Richer/Fatter).
Bikes like to be a little (fat). (Fat) = added torque! And that's what you "feel" in the performance of the bike. HP is great, but you can only really feel it in the higher RPM ranges and only then "if one really know what you're feeling and looking for"!. But, if you don't have the proper combination of HP along with torque, you really won't have much. So in reality bikes that are tuned to run just a little richer, run just a little quicker (torque) and better.
Just to give you an idea in differences. When I was racing, we'd go to the east coast at one race. Lots of humidity= less air, OK, so we'd (Lean) it down some, right. Then we'd leave an go to Phoenix, Hot & Dry = more air, So we'd (Fatten) it up some, right. You wouldn't think that there's a tremendous amount in the altitude differences between High Point NC. (Elev. 1,007 Ft.) and Phoenix AZ. (Elev. 1,117 Ft.) Some yes, but not a lot. We'd have to richen up 2 (main) jet sizes, or we'd loose pistons after 1 run! So the air densidy plays a factor as well. Start being a little rich (Fat) to be safe! Then adjust the ratio.
Just my thoughts here. Good Luck! :2thumbs: