Fuel Injection vs. Carburetor

Next to the differences between 2-stroke and 4-stroke, the fuel supply is the next big thing about bikes with internal combustion engines.

Regardless of its size or shape, your motorcycle or scooter needs some way to mix the fuel and air for proper combustion.

This can be done with either a carburetor or a fuel injection system

In this blog post, you’ll discover:

How a carburetor works, and the 5 parts of a CV carburetor
Whether it’s spelled “carburettor” or “carburetor”
Differences between fuel injection vs. carburetor
Which was the first motorcycle built with fuel-injection
How your bike’s name can tell if it has fuel injection

Prefer to get this information in podcast form? Listen to the 30 Minute Motorcycling Podcast episode about the differences between fuel injection and carburetors (and how the petcock works):

Quicklinks:

What is a Carburetor?
What is Fuel Injection?
- What was the first motorcycle with fuel injection?
- How does fuel injection work?
Quick Tip – How You Can Tell If Your Motorcycle or Scooter Has Fuel Injection
Fuel Injection vs. Carburetor – In Summary

What is a Carburetor and How Does It Work?

Image by Ralphs_Fotos from Pixabay

For decades, the carburetor was standard on almost every motorcycle or scooter. Today, they’re still around, although most common for small, cheap bikes. The carburetor works by carbureting the fuel and air mixture (hence the name) There are two main types of carburetors:

Slide carburetor
CV (constant velocity carburetor)

Since the CV carburetor is the most common one, we’ll focus on it for this blog post.

Parts of a CV carburetor:

Float bowl – where the carburetor stores the fuel
Throat – a narrow tube where air passes through
Venturi – a narrow passage where the fuel is compressed as it flows through it
Pilot jet – handles the mixture from idle to about 15-20% throttle.
Needle jet – where the fuel passes through when the amount of throttle is 20-80%
Main jet – controls the fuel mixture when your throttle is wide-open
Choke – used to temporarily enrich the mixture during cold starts
Petcock – controls the fuel flow

Discover More

What is the Choke?

Is it “Carburetor” or “Carburettor?”

The main difference is that “Carburetor” is used in American English, while “Carburettor” is used in Australian and British English.

What is Fuel Injection?

Also known as “EFI”, or “Electonic Fuel Injection,” this is standard on most modern motorcycles and scooters, for a few reasons. First of all, fuel efficiency is much better compared to a bike with a carburetor. Secondly, carburetors are much more sensitive to cold temperatures – It’s for this reason that fuel-injected engines don’t need chokes – they’re much better at dealing with cold starts.

Which was the first motorcycle with fuel inejction?

Back in 1980, Kawasaki released the Z100-H1 – the first mass-produced motorcycle to be built with fuel injection

How does fuel injection work?

Compared to carburetors, which are primarily mechanical, a fuel injection system consists of complex electronics and sensors connected to the engine. When they detect a change in either the throttle position or the engine speed, the sensors send a signal to the bike’s electronic control unit (or “ECU”). The ECU then uses the information from this signal to calculate when the fuel injectors should open and how much fuel the engine needs.

Quick Tip – How You Can Tell If Your Motorcycle or Scooter Has Fuel Injection

Sometimes, you can tell if a motorcycle or scooter is fuel injected in its name. Does it have an ”i” at the end? As in ”Kymco Like 200i”? Then the ”i” at the end signifies that it has fuel injection. It’s not always this clearcut, but if you see this “i” in the name of a motorcycle or scooter, now you’ll know what it means.