How to clean exhaust headers with harpic toilet cleaner

Car and motorcycle exhaust headers get dirty fast. They will pick up all the grit, dirt, bugs, mud, oil, grime, and water splashes from your front tire. Over time these contaminants will stain and rust away into your exhaust headers. Stainless steel and titanium exhaust headers are unable to stand up to this punishment.

There are 3 easy ways how to clean tarnished stainless steel exhaust headers for motorcycles. They all require some elbow grease and a cleaning medium.

Cleaning motorcycle exhaust with Harpic

For a quick clean, I like to use Harpic Power Plus Max 10 or Lysol Power Toilet Bowl Cleaner Gel. They both use Hydrochloric acid to help break down road grime, stains, and rust. Some other brands use Formic acid which is a weak acid whereas hydrochloric acid is a stronger acid. This is why these toilet cleaners work so well.

Hydrochloric acid is used in household and industrial cleaning applications to remove mineral scale build-ups such as calcium and iron. Perfect for just what we need to remove. Just make sure to use rubber gloves and eye protection.

Place some Harpic/Lysol in a bucket and see a paintbrush or an old toothbrush to dab it on undiluted.

Make sure to wear gloves and eye protection.

Polishing stainless steel exhaust headers rusty

Use a scouring brush or pad to scrub away tough stains on the exhaust. Make sure to fully wash away any Harpic toilet clean from around the exhaust pipes and surrounding parts. Startup your motorcycle to dry off the exhaust pipes to eliminate water droplet stains.

It is safe to use on Stainless and Titanium exhaust systems. But be careful on chrome exhaust systems and wash them off fast. It will stain aluminum so be careful on any exposed aluminum parts.

Cleaning motorcycle exhaust with harpic

Polishing stainless steel exhaust headers

The best way I have found how to polish stainless steel exhaust headers to a brilliant shine after using the Harpic toilet cleaner is to use a product called Autosol metal polish and an old rag cut up into a long strip.

Autosol removes corrosion, tarnish, and discoloration from chrome, aluminum, stainless steel, brass, and copper. So it works on just about every part of your motorcycle. It looks like toothpaste and can restore your exhaust pipes in no time fast.

Start by cutting up an old shirt, tea towel, or rag to a length of over 60cm. The longer the better, this will be used as a polishing buffing rag.

Feed the long rag through your exhaust headers and loop them around the pipe once. As you pull one end of the rag you will cause a buffing action completely around the exhaust header pipes. This is where we need to use the Autosol metal polish.

Keep adding metal polish to the exhaust headers as required. You will need to rearrange the buffing cloth as you come across sensors and hold down bolts.

The following video shows how this process is done correctly.

Autosol Metal Polish is a cool product as it restores that unburnished shine to your metal surfaces. It is formulated to enhance the brilliance of almost any type of metal including stainless steel, brass, copper, aluminum, cast iron, and more.

This paste removes tarnishing with ease whether used by machine buffing or by hand. It gets rid of unsightly tarnishing, surface rust, oxidation, and staining quickly and leaves your metal surfaces well-protected with an ultra-thin layer of wax. This helps to prevent problem build-ups in the future and is safe to use of exhaust headers.

Suitable for use in a wide range of metal polishing scenarios, and has been certified by NSF International as safe for use in food preparation areas and is both non-toxic and ammonia-free. But I still wear gloves to keep my hands clean.

Exhaust Cleaning Brush

A spinning exhaust cleaning brush is another way to clean rusted and heavily stained exhaust headers. I like that these brushes are made out of a tough soft foam that can bend to get into hard-to-reach spaces.

All you need is some of the Autosol metal paste mentioned above on the tip of the exhaust cheating brush. You can then use a battery drill at high speed to clean your exhaust. Start with a slow rotation to work the paste into the metal and the brush. You may need to remove your fairings to get access to all parts of the exhaust.

These brushes are mainly used for car rims and exhausts but work great for our motorcycle headers too. If you are after an easy way for polishing stainless steel exhaust headers then these spinning cleaning brushes are the way to go.

How to clean rusty motorcycle headers

How to clean rusty motorcycle headers
Rusty motorcycle exhaust headers

Rusty motorcycle headers require a lot more elbow grease to get rid of the surface rust. If it is just small pits of rust coming through the chrome exhaust headers then there are a few different products you can use.

  • Lime-Away Toilet Bowl Cleaner
  • Harpic/Lysol
  • CLR – Calcium Lime Rust All Purpose Cleaner
Harpic intensive cleaners for stainless steel exhaust
Finished How to clean rusty motorcycle headers with Lime-a-way

Lime-a-way contains hydrochloric acid, whereas CLR uses a combo of lactic acid, gluconic acid, and a few other solvents. Both do a great job on rust stains but CLR due to the extra ingredients seems to tackle certain stains better. But lime-a-way and Harpic will be cheaper and you may find you already have these toilet cleaners in your house.

For heavily rusted exhaust pipes a wire brush may be required to scrub off any loose rust particles. Use a small paintbrush to wipe on the toilet cleaner gel or the CLR liquid. Rub it in well and white a few minutes before washing it off. Wipe down the exhaust headers with a dry rag before you start it up to prevent any further staining.

Rusted pit marks will still be there but at least the motorcycle exhaust will not look shiny after using Limeaway, Harpic or CLR clear.

It is the fastest way I have found how to clean tarnished stainless steel exhaust headers.

Sodium hypochlorite vs hydrochloric acid for exhaust cleaning

In households, hypochlorite is used frequently for the purification and disinfection of the house. Many of the toilet cleaners I found at the shops use Sodium Hypochlorite as a base ingredient.

By adding hypochlorite to water, hypochlorous acid (HOCl) is formed:
NaOCl + H2O → HOCl + NaOH

Hypochlorous acid is divided into hydrochloric acid (HCl) and oxygen (O). The oxygen atom is a very strong oxidator. So if you do use hypochlorite-based gells you must add some water first to make some hydrochloric acid.

Read more:

If you want the best product to clean your motorcycle exhaust you have to look for a toilet cleaner that uses Hydrochloric acid as its active ingredient. This way you can use it undiluted it just works better as it is stronger.


motorcycle exhaust cleaned with harpic/lysol toilet cleaner

Cleaning tarnished stainless steel exhaust systems can be frustrating but if you use the correct products it will be easy. Hydrochloric acid in some toilet cleaners actually dissolves off all of the rust, stains, carbon, and road grime. Plus it’s cheap at your local supermarket.

If you have fairings it will be easier to remove them before cleaning the exhaust system. Usually, this only involves taking off a few bolts. If you want to remove the whole exhaust then this may require a few more specialized tools for motorcycle repair and maintenance.

Harpic and Limeaway are intensive cleaners for stainless steel exhaust systems and will make your motorcycle stand out in the crowd. For those that have a titanium exhaust like my Akrapovic Ti exhaust on the MT07 the Harpic Max 10 or Lysol power toilet cleaner will do a great job on it as well.

Remember to use gloves and eye protection when working with chemicals and wash off your motorcycle well. Maybe I will see your out on the road one day with your bright shiny exhaust.

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