Why is the exhaust pipe turning blue and how to remove it?

[MarcosSantiago]

Forum Sponsor

It's just heat. Higher performance engines have a lot of flow, which means more heat past the exhaust manifold. Modern pipes are short to a very hot catalytic box and don't cool down as easily. Any race bike has blue pipes.

If it suddenly happens on an old bike with chrome exhausts, it may mean a rich mixture and gas burning past the manifold, or a thin, single walled pipe.
You can put thermal coatings inside the pipe, but it's just normal on most bikes.

If you obsess about it with polishers, chrome won't last long. Looks great on that H2R.
Hell, some people are even faking it, poorly..

Are we talking about the same bike?

This is neither a higher performance engine, nor does it have a catalytic converter.
It is not a race bike either.
It is not fuel injected. It is not an H2R.

This bike has carburetors and it obviously has a mixture problem. Most likely a lean condition, not a rich condition.

No, it is not just heat, otherwise both pipes would look the same.

My 2 cents!

 

[Schneller]

Are we talking about the same bike?

This is neither a higher performance engine, nor does it have a catalytic converter.
It is not a race bike either.
It is not fuel injected. It is not an H2R.

This bike has carburetors and it obviously has a mixture problem. Most likely a lean condition, not a rich condition.

No, it is not just heat, otherwise both pipes would look the same.

My 2 cents!

+1, finally

 

[CafeRay]

This is neither a higher performance engine, nor does it have a catalytic converter.
It is not a race bike either.
It is not fuel injected. It is not an H2R.

This bike has carburetors and it obviously has a mixture problem. Most likely a lean condition, not a rich condition.

No, it is not just heat, otherwise both pipes would look the same.

My 2 cents!

Marcos, all I ask is that you read what I write.
"If it suddenly happens on an old bike with chrome exhausts, it may mean a rich mixture and gas burning past the manifold"

I can't tell anything about the right pipe from that picture.

See discussion here from a bike mechanic:

http://www.hdforums.com/forum/ignition-tuner-ecm-fuel-injection/16162-blue-pipes-rich-or-lean.html



I was a bike mechanic for several years for Yamaha & Kawasaki when I was younger, Back then everyone was just coming out with the 4cyl bikes and I remember the pipes bluing due to the customers letting the bike run with the choke on too long...running rich. Well when I started riding a real motorcycle Eveyone said your too lean your pipes are turning blue, your gonna burn up that engine!!!
Now after visiting the web site of Krome Werks I find this in the Q&A section:

Is exhaust bluing a warrantable condition?

No. All chrome plated steel exhaust pipes or mufflers will "blue" or discolor when the surface temperature reaches 900°F. This can occur if the fuel mixture is too rich. Instead of the charge burning mostly in the combustion chamber, the mixture continues to burn after the exhaust valve opens, down the pipe, causing extreme heat and bluing of the metal and its plated surface in the most restrictive areas.

If an engine could run lean enough to blue the pipes, you will notice a dramatic power loss and likely a seized piston.

This bluing definitely happens with bikes left on choke too long.

 

[CafeRay]

+1, finally

Two wrongs make a right?

Forum Sponsor