motorcycle carburetor-image from pixabay by emkanicepic

How To Tune A Motorcycle Carburetor? – Guide


February 23, 2022

A motorcycle carburetor is a machine or device that enables the proper amount of air and gas to be blended for use in internal combustion motorcycle engines.

Motorcycle carburation tunes the performance of motorcycles wheels racing motorsports. High-performance motorcycles custom-built motorcycles handcrafted motorcycles factory racing team racers HRC Honda Yamaha Suzuki Kawasaki Kawi KTM Ducati Aprilia Buell BMW Triumph

The most important part of a motorcycle is the engine, and nothing feeds it better than a finely tuned bike. A bike does not run very well with crappy gas, so you do not want to feed it crappy air either. This is where knowledge about how to tune a motorcycle comes into play.

How To Tune the Carburetor

How To Tune the Carburetor

When you are learning how to tune a motorcycle, there are some motorcycle tuning tips that you should become acquainted with.

First, motorcycle carburetors work by feeding the engine just enough fuel to keep it running cleanly and smoothly at idle or low speeds. At higher RPM levels, an engine needs more gasoline for extra power.

After you have set the throttle stop screw on your motorcycle check to see if your motorcycle carburetor is flooding. This happens when too much gas enters the motorcycle carbs. If this has happened to you even once after tuning it yourself or taking it in to be tuned, then chances are good that this will happen again.

When your motorcycle starts flooding, there are motorcycle tuning tips that will help you get it back under control. First, do not turn the motorcycle carbs upside down to drain them out. Next, try to lean the motorcycle slightly so that you can drain any excess fuel from one side of the motorcycle carburetors.

To overcome flooding problems in motorcycle carbs when your motorcycle dies at a stop sign or a light, try changing your motorcycle air filter. Usually, floods happen when dirt gets into carbs and prevents it from running properly. Replacing your dirty motorcycle air filter with a brand new one will help you start your bike again after flooding occurs.

After performing these steps several times during motorcycle tuning and motorcycle carburetor tuning. You should eventually get the hang of motorcycle tuning. If not, there is nothing wrong with getting a professional motorcycle tuner to help you out with motorcycle tuning tips.

How Does Motorcycle Carburetor work?

How Does Motorcycle Carburetor work?

The motorcycle carburetor mixes fresh air with gasoline and atomizes it into a fine mist so that the fuel can burn in the engine’s combustion chamber.

A motorcycle carburetor functions similarly to any other atomizer. It takes liquid and mixes it evenly with air so that the liquid evaporates instantaneously when exposed to an open flame or heat source. The motorcycle carburetor must do this in such a way as to maintain a high-velocity airflow through the venturi.

Parts of Carburetor

Parts of Carburetor

Float Bowl

The float bowl is the part that holds the fuel when you tip your motorcycle upside down. The main jet is what controls how much air and gas mix, next to the carburetor throat (the constricted area where airflow meets mixture). It regulates this by controlling fuel flow into the main air stream, through the venturi.

The needle valve controls fuel spray in pulses in response to the intake vacuum. In other words, it meters fuel to match engine demand in an ongoing, ever-changing manner. When you press on the throttle handle, it opens up a passage for more air. It then dumps extra fuel into that passage via holes or passageways right under the throttle butterfly valve plate.

For motorcycle tuning purposes, back off the idle adjustment screw enough so that the idle speed will be low enough for you to listen carefully as your motorcycle runs. Then adjust mixture screws until both cylinders are equally loud or equally soft.

To obtain optimum motorcycle performance, you will need to experiment with your motorcycle carburetor. It’s done by adjusting the mixture screw while the motorcycle is running. An adjusted motorcycle carburetor should idle at around 600-800 rpm and deliver maximum power.

Main Jet

The main jet is a component that controls the amount of air-fuel mixture from entering into the motorcycle engine. It works by allowing a certain volume of air to pass through a small opening. It also controls the motorcycle engine’s speed and acceleration by providing fuel accordingly.

Different motorcycle engines have varied sizes of main jets. On motorcycle carburetors, there is a notch on the top of the main body that denotes its size. This number can be 100, 110, 120, etc., which stands for their size in hundredths of millimeters (i.e.: 110 = 0.110 meters or 4 mm).

Air Screw

This adjusts how much air goes through the motorcycle carburetor’s venturi, which in turn affects how much fuel will be mixed with it. It also controls when that will happen by regulating when an air valve opens within

Needle & Seat

The throttle valve, or slide, has a long tapered needle attached to it that fits inside a matching taper in the carburetor’s main body. The needle is controlled by a spring-loaded clip that hangs off the bottom of the slide. When you twist open your motorcycle’s throttle, this opens up the passage from the float bowl to the engine. It allows fuel to flow into your intake tract.

This component controls when gasoline can enter or not enter through an adjustment to the motorcycle carburetor’s throttle slide in relation to its position.

What can happen if motorcycle carburetor needle & seat are neglected?

Neglecting motorcycle carburetor maintenance will cause sluggish performance and poor gas mileage. There will be an increase in emissions. If left unattended for too long, even small amounts of wear can lead to severely under 1eliable operation.

For example, many motorcycles use a single round jet for idle mixture and another single round jet for main fuel delivery. Some motorcycle carburetor kits use needle valves that cannot be disassembled. If needles are seated in the carburetor body, these motorcycle carburetors will be almost impossible to tune properly.

Choke Tube

A motorcycle’s air-fuel ratio (AFR) is controlled by twin carburetors under normal circumstances. They are operated by a vacuum system. This covers the throttle blades to prevent airflow, creating an area of high pressure in the manifold plenum chamber.

An opening inside the throttle body vents this excess pressure into the atmosphere or returns it to the low side of the intake manifold. This allows fresh air that has been “entrained” into the flow to be carried into and through the engine.

Motorcycle carburetor is cold, motorcycle engine has to be “choked” with an extra rich mixture of fuel and air. This is done by routing part of the incoming air/fuel charge through a tube that is inserted into the motorcycle carburetor.



Jeffrey Bryce is an experienced motorcycle rider with years of experience caring for motorcycles. His natural fondness for motorcycles have made him come up with, which is dedicated to answering and teaching you how to care for your bike with the care it requires. LetsGoForARide is the one of his important lifework in reaching out to communities of motorcycle enthusiasts on how to take care of their bike and choosing the correct spare part.