Discolouration on Crank Throws

I took apart my 2000 YZ426F everything looks good inside, but on the crank throws right above where the connecting rod joins to the journal, looks like it got high heat at one point. it has red and blue swirls like the header pipes get. Is this common, or should I really be worried about it. This is a high hour bike and I don't want to put hundreds or even thousands into this motor...

I believe those heat marks are from when the rod was installed onto the crank at the factory.

Bluing on the rod is bad.

its normal ignore it! Tried to find a pic from some old threads but couldn't. They come that way new.

Yep its normal. I believe I have a pic posted somewhere.



Not a great pic, but look at my first post in that thread and you can see the bluing on this bike also.

Ya mine are identical to that...glad to see they're normal... thanks for the fast reply, you guys rock!!!:)

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