"Blue" downpipes

[joelyvette]

About 2 weeks ago I got tired of the crud building up on my down pipes, so I dedicated a few hours of time and buckets of elbow grease to sand them down. Started with a 240 grit sandpaper and worked my way to 2000 grit. They came out amazing, just like new!

But now, after 2 weeks and various heat cycles, I am noticing that they are turning a deep blue almost purple color. An older friend of mine said that in Carb'ed bikes that was a sign of a rich fuel mixture and that something needed to get changed.

Would the same apply to my ST3, even though its EFI? If so, what map is recommended for the TOR's and K&N filter? I believe I have 20589 loaded right now.

Can someone give me some advice?

Thanks!

[Lush_trucker]

The blue color comes from heat.
I would be inclined to believe that would indicate a lean condition, not rich.
Our bikes have a system that pumps fresh air into the exhaust, this causes popping on deceleration and I think would cause the same extra heat in the exhaust that a lean condition would create.

In short, it is normal.

[mcteague]

I wish mine were blue! They very quickly went from shiny silver to bronze to a dark brown\grey. Way too much work for polish them up. Can't see them when riding anyway.

Tim

[Vallejo]

Originally Posted by mcteague

I wish mine were blue! They very quickly went from shiny silver to bronze to a dark brown\grey. Way too much work for polish them up. Can't see them when riding anyway.

Tim

Same. They're almost black now so at least it matches the bike

[joelyvette]

Originally Posted by mcteague

I wish mine were blue! They very quickly went from shiny silver to bronze to a dark brown\grey. Way too much work for polish them up. Can't see them when riding anyway.

Tim

With about 2 hours and the right sand paper they come out looking really good, and mine stayed shiny (and blue) until I got caught in some water.

If you have a small finishing sander it can really make it quicker on the easier to reach areas.

Going to see if I can get a half decent picture to upload.

[rand4ll]

Personally I think the blue looks awesome! And yes I would agree normal, mine are blue too.

[joelyvette]

Ok cool, i love the blue as well, just wanted to make sure that there wasnt anything wrong.


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[Malcolm21]

The blue is a chemical reaction in the metal from the heating and cooling cycles. You see it in our Triumph twins all the time. The only ways to avoid it are obsessive polishing, ceramic coating your pipes, our finding some double walled headers for your bike.

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[Deanoh]

What's wrong with heat darkening of the headers? Heat comes from power and I see the dark headers as a badge of honor that the engine is working hard and doing a good job. Shiny bright headers makes it look like the guy always just putts around like an old geezer.

[joelyvette]

Again, i dont see anything wrong with it. And i love the blue/purple color, it looks great to be honest. I just wanted to make sure there wasnt anything wrong.