How to Clean a Dirt Bike Carburetor?

This article may contain affiliate links. As an Amazon Associate we earn from qualifying purchases.

The carburetor keeps your ATV or motorcycle running at the peak efficiency. A significantly dirty carburetor will seriously affect the performance of your bike to a point where it might stop functioning properly.

When that happens, the first step you should take is to clean the carburetor. Carburetors are complicated components but they should not make you feel intimidated when it comes to the cleaning part.

By going through the right process systematically, there is no reason to avoid cleaning your bike’s carburetor. Before you take carburetor off & disassemble it, you will have to gather several tools. And because most of the parts in a carburetor are delicate, you will have to take several precautions.


Clean Dirt Bike Carburetor

Tools You Need for Carburetor Cleaning

Safety is the very first thing you will have to consider when cleaning a carburetor. In addition to wearing safety glasses, you will have to use safety gloves throughout the process to protect yourself from chemicals in the gasoline, which can irritate your skin.

After getting the two items, you will have to ensure that your working area is clean and properly lit. The cleanliness is important when undertaking any classic bike work, but it is more important when working on carburetors. Here are the tools you require when completing the cleaning:

  • The service manual
  • Several rags
  • Carburetor cleaner
  • Hex key / Allenwrench
  • Screwdriver
  • Small screwdriver
  • Socket wrench
  • Wrench
  • Compressed air
  • Medium / low strength thread locker
  • Gloves

The service manual is the most important tool. The market offers many kinds of bikes, which means that carburetors are not made the same way. The purpose of the service manual is to show you the main differences. Additionally, it will fully describe the size of the tools you need to do the cleaning.

And even though the compressed air is vital, it can be hard to access the industrial compressed air. If it is unavailable in your area, do not panic. You can purchase pressurized air cans at the retail locations.

The tools you require are the basic ones. However, the screwdrivers have to be in their new condition because you will use them to remove the brass jets. If the driver does not locate them properly, it will damage them. The typical tool requirements include crosshead and straight blade screwdrivers, metric and standard socket sets, steel rule and carburetor cleaner.

Remove Carburetor From Your Dirt Bike

Typically, bike manufacturers use a circular clamp or two bolts to retain the carburetor on the bike’s inlet manifold. Before you start removing the carburetor, remember to turn off the primary fuel supply and use the small screw in the bike’s chamber base and a hose to drain the bike’s float chamber.

On most carburetors, you will easily remove the slide and control cable after removing the carburetor from the engine.

The part of your assembly will involve removing the float chamber. Turn your carburetor upside down to see the four screws that retain the float chamber – some units will feature three screws while others come with a wire clip.

After you have removed the screws, you will need sharp tap with the plastic handle of your screwdriver to loosen the chamber from the gasket properly.

After removing the float chamber, you will see the main floats, jets, primary jet also known as pilot jet and the overflow pipe. The floats are delicate and you should, therefore, remove them first.

Manufacturers use plastic or brass to make the floats but the former material is prone to leaking and you should, therefore, inspect them to ensure that they do not contain any gasoline.

Floats have to pivot freely on the pressed-in pin, generally fitted to the Keihin and Mikuni carburetors. You should be careful when removing the pins because the aluminum stand, which retains it, is more susceptible to breaking. When tapping, support it on one side.

Most carburetors come with a two-jet system. The first jet controls the flow of fuel from the idle to the one-third throttle openings while the second jet controls the flow to the other two thirds.

Due to their small size, the Jets get restricted or blocked and that will cause an insufficient or lean running condition in the throttle opening period. Generally, the bike will need some amount of choke to negate or overcome the problem. The fix involves cleaning the jet thoroughly or replacing it.

Another item you will have to remove from your bike’s carburetor is the fuel or air adjusting screw. To know the type your carburetor features, examine the location of screws relative to the slide.

A screw situated on the side of the carburetor’s air filter is the air adjusting screw and one situated to the engine side is the fuel adjusting screw.

The tapered screw has a significant effect on the mixture strength – lean or reaches – in the throttle opening’s first third and works along with main jet. Before removing it, you will have to check the position of the screw.

Manufacturers set the screw at several turns from the fully closed position and you will have to put it back to that position during the reassembly.

Steps to clean the carburetor

First thing to clean is the float bowl. Use the rag and carb cleaner to clean it and then clean and inspect all the other parts of the carburetor. Flush out all holes in the body of carburetor with the carburetor cleaner and then blow through them with the compressed air.

When doing that, use the goggles to protect your eyes because you will eject fluids and dirt particles from the holes.

Reinstall the Carburetor

To reassemble to the carburetor, you just need to reverse the disassembly process. However, before reattaching the float chamber, you will have to check the float heights.

The height setting of the float is likely to affect the functioning of the engine and the mixture. You can adjust the height by bending the metal tang, which applies the pressure the engine’s needle valve slightly.

If you bend it too much, you will cut off the delivery of fuel into the chamber, therefore, minimizing the height of fuel. The workshop manual will provide you with the appropriate height, which the manufacturer measures with the carburetor inverted from the face of the gasket to the top part of the floats with a ruler.

Each time you overall your bike’s carburetor, you will have to fine-tune its air adjusting screw. After you have reattached carburetor properly and started the engine, allow the engine to warm up to its normal working temperature.

Adjust the screw in quarter turn increments. If your engine speeds up, know that the adjustment is important. If it starts slowing down, reverse the adjustment.

Why Do You Need to Clean the Carburetor on Dirt Bike?

A clean carburetor keeps your dirt bike in a peak performing condition. A dirty carburetor steals power from your bike and, in the worst-case scenario, it can bring the engine to halt.

When this happens, your first step should be to cleanse the carburetor. Carburetors are complex components but, if you need to clean it, that shouldn’t intimidate you.

How do You Know if Your Carburetor Needs Cleaning?

A healthy heart is important for a healthy life and that is true for engines. The carburetor is the heart of your motorbike. Cholesterol in your heart can adversely affect your health.

On the other hand, gummy fuel residue and dirt in the carburetor will bog it down. That can hinder the performance of the engine and engine will finally fail.

To maintain efficient operations, you will have to keep the carburetor clean. Here are some of the signs that will tell you it is time to clean the carburetor.

  • The engine fails to start. If the engine cranks or turns over but fails to start, the carburetor might be dirty. A lot of dirt will prevent attainment of proper fuel and air combination. The fuel will not travel to the engine. The result is turnover but no actual start or catch.
  • It is running lean. If the balance of gas and fuel is thrown off, the engine is running lean. Generally, the ratio of air to fuel is 12:1 or 15:1 and too much air or little fuel will cause popping or sneezing sounds during the intake. One of the major reasons is insufficient fuel getting to the carburetor.
  • It is running rich. An engine that runs rich indicates that the fuel is excess and the air is insufficient. If this happens, the engine will produce black smoke.
  • It is flooded. Presence of debris or dirt in the carburetors fuel bowl will block the needle valve, therefore, preventing its closing. That causes an overflow in the carburetor. That might cause flow out of the fuel and the spark plug gets wet.

The carburetor might not be to blame for some of the issues, but mostly it is usually the culprit. With the signs, you will always know when it is time to do the cleaning.

Is it Hard to Clean Carburetor?

It will highly depend on the bike but generally, it is not hard if you are mechanically inclined and you have a manual. A shop will charge you a lot of money, so cleaning it the DIY is a good decision.

How Often Should You Clean the Carburetor on Dirt Bike?

Most bike owners are aware of the routine maintenance they need to perform on their bike’s various parts, but there is often confusion on how often one should clean the carburetor.

The rule of thumb is, you should clean your carburetor at least once every two years – that’s pretty much the only maintenance exercise you need to perform on a carburetor.

But taking the carburetor apart is challenging, so it’s fine if you choose to clean it only when necessary. For some, this can be once in every few months, for others it could be once in every few years.

If you regularly ride your bike, you may need fewer cleaning sessions compared to someone who rides less frequently. Regular rides help clean the carburetor.

Therefore, those who don’t ride often have to clean their carburetors more often because bikes that are barely used tend to build up dirt and grime in the carburetor quickly.

You can use a fuel filter to keep your carburetor clean for longer. Fuel filters catch the tiny peddles that the screens and petcock in the carburetor miss.

Besides, after every month, you should flush out all the premix fuel. Sediments are more likely to accumulate in your carburetor if you usually use pump fuel.

Can You use WD40 to Clean Dirt Bike Carburetor?

WD-40 is a strong solvent-based cleaner that washes away oil, grime, and tough carbon deposits. The WD-40 cleaner spray is supper effective in cleaning the carburetor, unpainted metal parts, and the throttle body.

What distinguishes WD-40 is its dual-action cleaning system. First, the solvent breaks down the tough baked in dirt. Its powerful spray then blasts away the dirt leaving no residue behind.

The results are efficient engines that start easily and fast and level to a consistent and smooth idle with no stalling.

W-40 works not only well in dirt bikes but also in new and old vehicles and in equipment like tractors, lawnmowers, weed trimmers, boats, and other gas-powered equipment.

Besides, it’s doesn’t affect catalytic converters or oxygen sensors and you can safely use it on most of the unpainted metals.

When using chemical or compressed air, it’s prudent that you use ear and eye protection. Ideally, you should replace the o-rings and the gaskets in the carburetor during the cleaning process.

As you clean, use a straw to shove the solvent through each of the passages in the carburetor and ensure the cleaner flows completely to across the passages.

Then, blow in compressed air to ensure the passages are clear.

If there is any float bowl discoloration, fuel staining, or any irregularities within the carburetor, you should remove them through soaking them in a cleaner or by any other means or else your carburetor will likely develop jetting problems in the future.

Can You use Brake Cleaner to Clean a Dirt Bike Carburetor?

Using the bake cleaner to clean brakes is obvious but it can be useful for other purposes too. The brake cleaner is a multi-purpose cleaner, for the most part.

What makes is so great is that it dries fast. You can use it to clean brake fluid, grease, or oil – it cleans almost everything effectively.

The brake cleaner, therefore, makes for a great carburetor cleaner. You can use it safely on your carburetor, and it’s effective because it’s formulated to dissolve grime and grease buildups just like carburetor cleaners are.

Generally, there are two types of brake cleaners: chlorinated and non-chlorinated. You should avoid chlorinated cleaners because their aggressive chemical makeup can harm your health.

Conversely, chlorinated brake cleaners are safe and thus preferable. You can spray it on anything without any issues.

You shouldn’t use brake cleaners on powder-coated materials, though. The powder will likely get sticky; this will mess up the perfect finish.


The carburetor is the component in which air and fuel mix before they are channeled into the engine. Gas often dries out and crystallizes on the walls of your bike’s carburetor resulting in a sticky film that enlarges over time.

You can keep your dirt bike’s carburetor in good shape by cleaning it with particular cleaning products. A clean carburetor helps maintain your bike’s engine power as well as gas mileage.

But before you start cleaning your carburetor, remove all rubber and plastic components because, often, cleaning solvents are damaging them.

When an engine is not used for a long period, the fuel starts to degenerate. Ensure that after cleaning up your carburetor, you replace the fuel in the tank before you turn on the engine – otherwise, the same carburetor issues will soon recur.

In a nutshell, similar to when cholesterol builds up in the heart, gummy fuel residue clogs a carburetor. The blockade, in turn, eats into your engine’s power and often leads to “engine failure”.

You can keep your bike in tip-top shape by regularly cleaning the carburetor.

Josh Berry - MotoShark Editor
Josh Berry
I'm a off-road enthusiast, extreme sport fan and the editor of MotoShark. If you have any questions or suggestions regarding this article, please leave a comment or contact me.

Leave a Reply

Your email address will not be published. Required fields are marked *