How Does A Carburetor In Bike Work? A Complete Breakdown

A carburetor is a small device in a gasoline engine that helps to control and mix the air entering the engine. As the weight and design of a motorcycle engine are different than that of a car’s, the carburetor used in the bike is also different. Carburetors in bikes are being replaced by fuel injection systems in modern bikes, with the improvements in motorcycle technology.

Learning about carburetors is crucial for new riders interested in classic motorcycles and dirt bikes. It can help you fix certain engine problems while riding solo and make you more aware of your motorcycle. In this blog, we will explain the carburetor function in bikes, its components, and the types of carburetors in a bike. Keep reading to know more.

A] What Is A Carburetor In A Bike?

The carburetor is an essential part of a bike engine, it is responsible for creating the combustion required for generating power. Carburetors are mostly present in classic bike models or bikes used for dirt racing and off-roading. A carburetor precisely intakes air from the atmosphere and mixes it with fuel in the engine cylinder. 

The combustion created by this mixture is then burned to create energy and propel the bike forward. The proper function of the carburetor is essential for a smooth riding experience. Bikes that do not have a carburetor do not face this problem as they use a fuel injection system. A fuel injection optimizer can be used in such cases to autotune the engine to its best operational parameters.

B] Components Of A Bike Carburetor

• Venturi: Venturi is a pipe-like structure in the center of the carburetor, responsible for passing the air and fuel mixture. Its thickness depends on the engine’s CC and speed.
• Throttle Valve: The main function of a throttle valve is to regulate the mixture of air and fuel in the combustion chamber.
• Choke: The choke regulates the intake of air, enriching the fuel-air mixture while starting the engine. The choke usually stays open; however, if the air entering is more than required, it rotates to create a block.
• Float Chamber: The Float chamber is an intermediary fuel storage bowl right before the fuel enters the combustion chamber.
• Float Valve: The Float valve regulates the fuel supply into the float chamber. It ensures the float chamber is constantly refilled.
• Mixing Chamber: The mixing chamber is the primary component of any bike carburetor. It is the chamber where air and fuel mix to create a combustion mixture.
• Metering System: The metering system supplies fuel to the engine. It adjusts the quantity of fuel supply by adjusting to the pressure in the venturi.
• Idling System: The idling system connects the venturi with the float chamber. The idling system is built into the carburetor to supply fuel to the float chamber during idling time.
• Strainer: The strainer removes the impurities from the fuel before it enters the fuel chamber by staining them.
• Anti-Dieseling Solenoid: If the emission control systems of the bike become hotter, the engine can ignite before the stroke. Anti-dieseling solenoid prevent preignition.

C] Types Of Carburator In Bike

• Constant Velocity (CV): Constant velocity carburetor has smooth throttle response and offers better performance. The CV carburetor has a butterfly-style valve at its throat that opens when vacuum pressure lifts it up.
• Slide Type: The slide-type carburetor also known as the mechanical slide carburetor opens and closes the carburetor slide according to the rider’s throttle input. Mechanical slide carbs are best for sport bikes and off-roading.

The choice of carburetor also depends on the type of engine. Two-stroke and four-stroke engines have different throttle requirements. It is best to know the difference between two-stroke and four-stroke engines and choose wisely.

D] Step-By-Step Guide To Bike Carburetor Function

Step 1: Air Intake

The motorcycle carburetor function starts by taking in air from the atmosphere and filling in the venturi. The choke valve prevents extra air from entering the carburetor. In the mechanical slide carburetor, the air is drawn according to the throttle given by the rider.

Step 2: Venturi Effect

When the air is taken in, it passes through the narrow pipe of the venturi. As the air passes through this narrow section, the velocity of the air increases. This is called the venturi effect. The venturi effect decreases the air pressure in the cylinder.

Step 3: Fuel Metering

The carburetor has a fuel jet that meters the amount of fuel drawn from the float chamber into the air stream. The fuel composition is determined by the throttle valve and the amount of fuel drawn is based on the fuel’s demand by the engine.

Step 4: Fuel Atomization

Fuel atomization is the process of breaking the fuel into smaller particles. The atomization process is achieved by mixing the fuel with the fast-moving air. Atomization is a crucial process for effective combustion. Atomization efficiently mixes the fuel and air to create a highly combustible mixture.

Step 5: Throttle Valve

The throttle valve is a passage for more air to enter the piston chamber. The throttle valve is regulated by the rider using the throttle grip. The rider can regulate how much air is entering the engine using the throttle valve. When the throttle valve is open, more air enters the engine and mixes with the fuel.

Step 6: Air-Fuel Mixture Formation

The mixture of air and fuel in the perfect ratio is crucial for efficient engine operation. The use of carburetors in bikes ensures the mixture is within the optimal range for combustion before the air-fuel mixture is used in the combustion chamber.

Step 7: Combustion Chamber Delivery

Combustion chamber delivery is the most crucial process in any carburetor. The carburetor injects the pre-mixed fuel-air combination into the combustion chamber. Meanwhile, the fuel supply stays intact as the fuel is continuously supplied by the float chamber. As the mixture enters the combustion chamber, the piston compresses the mixture during the compression stroke.

Step 8: Ignition and Combustion

When the piston reaches the top of the chamber, the spark plug and the spark plug ignite the compressed air-fuel mixture, combusting it. The force produced by this combustion pushes the piston down and generates the power required to push the motorcycle forward.

Step 9: Exhaust Stroke

As the piston moves downward in the exhaust stroke, the burnt gasses and fuel present in the combustion chamber are expelled.

Step 10: Cycle Continuation

After the burnt gases are removed from the exhaust, the piston moves upward once again. The cycle repeats itself over and over until the engine is revving. The work of the carburetor is based on the engine’s demand.

Conclusion

Carburetors are an essential part of a motorcycle engine. They are responsible for ensuring the optimal mixture of fuel and air for internal combustion engines. A well-functioning carburetor is essential for preventing backfiring and producing proper torque. Knowing how your carburetor functions can be crucial to repairing it yourself and avoiding problems during a solo ride.

To further enhance your safety while on a long ride alone, make sure to always wear a bike riding gear full set. Staying protected from head to toe at all times can help you avoid injuries in case of a crash. If you are looking for premium-quality bike riding gear, visit Bikester Global Shop today!