What's THIS?!!!

Big O

Physicist Genii
Donating Member
I've never seen this before and this is not a good pic, but I've go some bluing on my front forks where the fork seal does most of the rubbing up and down. It's about 1 1/2 inches long and on both forks but different widths on each.
What is going on?
Sumbody hep me...

It does look like heat effect on stainless but it would take a lot of heat to discolor like that - like the heat of an exhaust. Maybe it is irridecence (sp?)?

Irridecence is the same thing you see on water when an oil drop is dispersed on the water surface. It looks like a rainbow and is due to atomic sized particles reflecting and absorbing light in a certain pattern. The fork slides could get polished to that level and then an oil film may cause the rainbow to appear? Again just speculation but may work.
I expect it's heat and friction, but like Sierra said it should take a LOT of heat to discolor the metal. The forks aren't leaking, and I can't wipe off the irridescence (sp) from the thin film of oil. Hmmm....my mechanic is closed until Tue and I'll be in Laguna by then.
Another thought I had was the color might be from a worn coating? I think the slides are coated with metallic low friction depositions (titanium or nitrides?). If this extremely thin coating was to wear out, it may have the effect of refracting light like the oil does.

Do your forks stick or resist sliding over those blue marks? If not I wouldn't worry about them.
I've seen forks pitt , rust , finish flake off , dis-colour , but never have a bluing thing . Is it both stanchion tubes Owen,or is it just one ? Friction produces heat, heat can blue things...but yer gonna need a truck load of friction .
When yer flying thru the air catching big bumps (motocross), yer puttin' one heck of a load on yer front suspension . Never enuff to blue it thou . You haven't etched the metal with some new type of cleaner have you?
I'll keep diggin' let you know if I find something .

Exellent brain quiz....thanks Big O .
O ya.....Big O....get that front up in air by way of a front stand that sticks in the bottom of the stem for the triple tree's . Or by jacking it up some other way , now grab the front end and give her a shake to make sure nuthin' is loose in there , you could also walk it and hammer the front brake an listen an feel for noises and clunks....

DO IT BEFORE LAGUNA....just me , paranoid Rubber .

Look in to it Owen.....RSD.
It won't wipe off. And it's not scored, I got Suzuki bike wash on it but rinsed it all off. I got Protect-All cleaner on it but I've done that before with no problem.

No head shake from the steering head.

Maybe I got something under the fork seal that rubbed it, but that would score it, (it does have little lines like scoring but I can't feel it) but the color change....hmmmm
I asked my mechanic about this and he said it was from the heat and there's nothing you can do about it, but it will be ok. Ok, I feel, better!