Why does motorcycle exhaust turn blue?

Are you worried about why your exhaust header has turned blue? Can this be cleaned to revert to the shine of the chrome?

The exhaust is too hot. There are a few reasons for this, your engine is running lean, your engine is running rich, or you have been standing idle for a long time, and the heat is not being dispersed due to no air running over the exhaust pipes.

Why are my motorcycle pipes turning blue?

It’s simple; your exhaust is too hot. If your engine is running lean, the temperature will build in the exhaust and cause bluing. Bluing commonly occurs on chrome pipes and gold colour on stainless steel.

Running rich can cause the same problem: the fuel will ignite and burn in the exhaust header and not the combustion chambers, sharply increasing the exhaust temperature.

A burned valve will also increase the temperature, as will incorrect timing. There are so many reasons.

There is a myth that blue exhaust pipes are caused by running lean, and gold is because of running rich. This is a myth and is wrong.

If you stand for long periods at idle, then your exhaust is not being cooled by air flowing over the exhaust surfaces. Blueing can occur in this situation.

How do you get blue off motorcycle pipes?

It’s a simple procedure in most cases. Allow your motorcycle to cool down to touch the exhaust and wash the exhaust with a decent detergent to remove any road debris and excess dirt and grime.

Dry the exhaust thoroughly. With a microfiber cloth, apply a little chrome cleaner/chrome polish and rub in circular motions. This part cannot be rushed, so take your time for the best results.

Use a liquid polish. It’s slightly abrasive and easier to apply. Be careful not to rub very hard and remove a chrome layer.

When the blueing has been removed, buff to the original chrome lustre.

What does a blue exhaust pipe mean?

A blue exhaust means your exhaust pipe has reached 293 degrees Celsius or 560 degrees Fahrenheit, pretty hot, and it will cause a severe burn and ruin your motorcycle boots.

Your engine could be running lean; this means you have more air than fuel which causes a hotter burn of the fuel that will blue your exhaust and possibly damage your spark plugs.

Running rich can cause the same symptoms but with the opposite problem. A rich engine has too much fuel compared to the ratio of air required.

Excess fuel can enter the exhaust system and ignite in the exhaust pipes. This causes the exhaust to become hotter, and bluing occurs.

Your motorcycle will run rough and maybe stall as you try to accelerate from a standstill in both situations.

How do I stop my chrome exhaust from bluing?

Keep the motorcycle well maintained and serviced. Don’t sit idle for an extended period allowing the exhaust temperature to rise due to the lack of air flowing over it.