Honda CB350 / 4 ultrasonic carburettor cleaning

One of our customers kindly sent some photographs of his Honda CB350 / 4 carburettors before and after cleaning with an ultrasonic cleaner.

One of our customers kindly emailed some photographs of his Honda CB350 / 4 carburettors before and after cleaning with an ultrasonic cleaner. The text below is from his email.

I Just used my 6 Ltr ultrasonic bath for the first time on some old carbs. The carbs are from a 1972 Honda CB350/4 and they were all quite badly gummed up. I used the carb cleaning solution diluted as instructed (10:1) and heated the water to 65 centigrade. I cleaned them (the bike has 4) one at a time for just 20 minutes each. Please find attached 5 before and 5 after pictures of the dirtiest carburettor.  Regards, Peter

The model Peter bought was a 6 Ltr ultrasonic cleaner with a simple dial adjustment for the time and temperature control. The carburettor cleaning fluid was included free.



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6 Ltr ultrasonic tank that Peter used for cleaning his carbs


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Carburettor Cleaning fluid

Ultrasonic carburettor cleaning fluid in 1 Ltr and 5Ltr bottles.

Our carburettor cleaning fluid has been formulated specifically for use with an ultrasonic cleaner, for cleaning carburettors, valves, fuel injectors, engine parts etc. It safely and quickly removes contaminants including general soiling and dulling, oxidation, carbon, petrol residue and grease etc. It works very well on alloys and aluminium castings, not only removing the physical dirt, but also it visually brightens dulling that occurs over time. Obviously it can’t make a component look like it did when it first left the manufacturer’s factory, but results are very impressive. The cleaning process won’t damage, corrode or darken metal components. Safe on brass, aluminium and other sensitive metals. It is also safe with O rings. Mix the concentrate 1 part solution to 10 parts water. (1 Ltr bottle makes 10 Ltr of working solution).

The fluid can be used many times until it looks dirty. There’s no specific rule about when to change the fluid, but the idea of an ultrasonic cleaner is for deep and thorough cleaning. If your fluid looks like pea soup, it’s time to change it!


The carburettor cleaning fluid is a concentrate and is added to water at a ratio of  10: (1 parts cleaning fluid to 10 part water). For heavily soiled components, this can be strengthened to 7:1. The working temperature of the ultrasonic cleaner should be set between 50 – 80 degrees centigrade. After cleaning rinse with clean water and leave to dry. Always test before use on new applications.

Visit our website for more information: Best Ultrasonic Cleaners fluids

1 litre bottle of ultrasonic carburettor cleaner

1 Ltr carburettor cleaning fluid

Free UK delivery (sorry, we can only ship fluids to the UK).


5 Ltr ultrasonic carburettor cleaner

5 Ltr carburettor cleaning fluid

Free UK delivery (sorry, we can only ship fluids to the UK)


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A bikers guide to ultrasonic carburettor cleaning – how to pick an Ultrasonic Motorbike Carb cleaner?

A bikers guide how to clean a carburettor with an ultrasonic cleaner. Which size and model to buy?

We all know the old saying that a grain of sand in a carburettor can stop the most powerful of motorbike engines. And it’s true. In the World of carburettors, cleanliness is king.

Having owned motorcycles on and off for more years than I like to admit and having rebuilt a few engines, from old BSA Bantam (D2), Norton Commando 750 (fastback) and a Ducati (250 Desmo), back in the day I would soak the carburettor in a bucket of degreasing solution for an hour or two, then rinse with water and blow it off with an air gun. Simple, but not really very efficient.

carburettors before and after cleaning

Technology has advanced over the last few decades and when it comes to cleaning a carburettor and engine components, the accepted best practice is to use an ultrasonic Cleaner. Without getting too bogged down in the technical detail, an Ultrasonic Cleaner has a component called a transducer that generates sound waves, that in turn produce microscopic bubbles that very effectively dislodge dirt, grime and petrol residue from the intricate parts of a carburettor that would otherwise be almost impossible to get to.

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Using an Ultrasonic Cleaner requires no special knowledge or skill. All that is needed is water and a specific cleaning fluid to put into the tank. The unit is then plugged into a domestic power socket and the built-in heater raises the temperature of the water & cleaning solution mixture to around 60 degrees centigrade. Place your dismantled carb in the tank, after removing float bowls and jets, and turn on the ultrasonics. Normally around 15 – 20 minutes is a sufficient cleaning time. Remove the carburettor, rinse and leave to dry. Not only will the carb be deep cleaned internally, but the alloy casting will look bright and clean. NOTE: Some castings were dull when new and obviously the ultrasonic cleaning process can never make your old carb look better than the day it left the factory.

Which Ultrasonic Cleaner should I buy?

I have a mantra about the selection process. Obviously the price is a main consideration, but above that – SIZE MATTERS. I can’t say that enough, so I will repeat – SIZE MATTERS. Several customers make a purchase by guessing or estimating their carb will fit into a particular machine. And when the cleaner arrives, they realise that its a bit too small and phone me to exchange it for a larger ultrasonic tank. That isn’t a problem, but it costs you the customer money to post it back to us and it’s a bit of faffing around. The golden rule: measure twice, purchase once.

Ultrasonic cleaner with a bank of 4 motorbike carburettors

It’s far better to try and get it right first time. And the best way is (if you can) to actually measure the overall dimensions of your carburettor. This isn’t always possible if the bank of carbs are still fastened to the bike and it can still end up being a “guesstimate”. Also, you will be removing some of the carb parts such as float bowls, slides, jets etc and this will reduce the overall required tank size. I think that if you can afford it, get something a bit bigger than you estimate. If you try to cram a small tank full of parts, the cleaning will not be as efficient as putting them into a larger tank. As the saying goes, “what will hold more will hold less”. Do you get the idea?



Degassing – what’s that about?

Degassing is available on some models and is an addition function which, after a change a cleaning solution, quickly removes air from the liquid that in turn, makes the cleaning process more effective. This is especially useful when cleaning carburettors. Additionally, the cleaning power can be increased or reduced depending on the items being cleaned which means that delicate products can be cleaned gently. It does however, add a bit more money to the price.


If you look through all the models we sell, the choice can be a little confusing. To help sort the wheat from the chaff, so to speak, shown below are the most commonly purchased Ultrasonic Cleaners for cleaning motorbike carbs. The 3 Ltr tanks are good for individual carburettors. If you need to clean a bank of 3 or 4 without splitting them, you’ll need a 20 Ltr as a minimum.

What exactly is ultrasonic cleaning? – MORE INFORMATION

3 Ltr Ultrasonic Cleaner with dial adjustment – (suitable for individual small carbs)

  • Tank Size (internal): 240 x 137 x 100mm
  • Wire Basket – included (L: 220mm x W: 130mm x H: 75mm)

3 ltr ultrasonic cleaner with dial adjustment

3Ltr Ultrasonic Cleaner with digital adjustment – (suitable for individual small carbs)

  • Tank Size (internal): 240 x 137 x 100mm
  • Wire Basket – included (L: 220mm x W: 130mm x H: 75mm)

3 ltr ultrasonic cleaner with digital adjustment

9 Ltr Ultrasonic Cleaner dial adjustment – suitable for medium size carbs

  • Tank Size (internal): 300 x 240 x 150mm
  • Wire Basket – included (L: 280mm x W: 230mm x H: 115mm)

9 ltr ultrasonic cleaner with dial adjustment

20 Ltr Ultrasonic Cleaner – suitable for large carburettors and a bank of 4 or 6

  • Tank Size (internal): 495 x 295 x 195mm
  • Wire Basket – (included) L: 465mm x W: 270mm x H: 125mm

20 ltr ultrasonic cleaner with digital adjustment

And finally, don’t forget the all important cleaning solution because an ultrasonic cleaner by itself won’t breakdown the petrol and grease. Additionally, when you’ve cleaned your carb, you want it to look the part and the use of a cleaning solution will give it the cosmetic “wow” factor. Cleaning fluids can be found here.

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