Just like our bodies, our motorcycles are complex but at the same time very simple. Heck, we only need air, fuel, and spark – the same can be said about a motorcycle.
The Carburetor: The Motorcycle’s Lung
We are going to dive in on this series to talk about various motorcycle parts and how they work, that way, you better understand how and why they function. First, we want to talk about our good friend, the carburetor, aka the lung of your motorcycle.
The Carburetor has one job
Its main job is to distribute the perfect amount of air mixed with fuel to the beating heart of the engine. Just like your lungs, if you hold your breath for too long you’ll choke, and/or if you breathe too fast continuously you’ll eventually just pass out. It is a very delicate process, and each motorcycle is unique to its own carb and mixture but in general, it’s all the same reasoning.
136 years and counting
Before the modern fuel injection system, these carburetors have been around for well over 100 years invented by Kari Benz in 1885 and patented in 1886, that’s 136 years! This revolutionary invention opened up doors for many internal combustion engines and, as we all know, the motorcycle was born.
Let’s take a technical dive into the carburetor
All of these internal combustion engines have various versions of a carburetor, some use one and some will use multiple ones but all with the same principle in mind. With a basic carburetor, you have an open pipe usually called the “throat” which the air passes into the manifold of the engine.
The air will narrow through a butterfly valve called the throttle valve – a rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it completely blocks the flow of air. This valve controls the flow of air through the carb throat and thus the quantity of air/fuel mixture it delivers. The throttle cable is connected to the motorcycle accelerator throttle grip.
When the throttle is pulled fuel is introduced into the air stream through small holes at the narrowest part of the venturi. All of these components and jets should be adjusted accordingly to get the perfect mixture and keep your engine running. Along these steps, you also have a choke that is critical when the engine is cold.
In those situations the engine needs a richer mixture (more fuel to air). To provide the extra fuel the choke comes in place, this is a device that restricts the flow of air at the entrance to the carb, before the venturi.
A reference point never hurts
This is a lot to take in, we know. It’s important to get an understanding of how this very simple but complex machine works. It’s vital for your engine and as mentioned it works like the lung of your fire-breathing machine aka carb motorcycles. You can find the complete details and breakdown here The Carburetor if you want to get a complete breakdown.
Get your hands dirty
We all learn differently and that’s ok, some of us like to read instructions, some of us like to watch tutorials and some of us just want to get our hands dirty. Whichever way you want to learn, get right down to the gritty and dirty and clean your carb. I would highly recommend it to get a great idea of just how it works.
I also would recommend if you are doing it for the first few times take photos of each step so that you have a reference to reverse the process and put it back together. Also, I recommend you get the manual for said carburetors so that you have the details to know how your particular carburetor works.
Such a small part
It’s all in the details and the smallest little components, who knew? We keep saying it’s so simple but it’s way more than that. Once you have mastered your carburetor your confidence we guarantee will skyrocket. It’s intimidating at first and you might have small moments of panic when you have the whole carb tear down in front of you, but rest assured it’s ok, you got this!
With many many brands and types of carburetors out in the wild, it can be a little intimating. From CV, to S&S to Mikuni, plenty to choose from and each one has its own advantages – Don’t be afraid to ask questions. These carburetors are so small but they play a huge part and you will learn to love and hate them all at the same time, in any case, you got this and as always feel free to ask our motorcycle experts questions.
Now go and get your hands dirty and enjoy the road, friends.
Enrique is a creative originally born and raised in the Mile High City of Denver, CO but in 2021 he skipped town to the rolling hills of North Carolina for a quieter kind of life. He specializes in visual storytelling and finding a voice for a narrative. With over 15 years experience in the industry, he brings professionalism along with experience to every project.
Find him on Instagram or see his work here.