Motorcycle Carburetors

Understand Your Motorcycle Carburetor to Get the Best One  

How Do Motorcycle Carburetors Work?

If you have ever had the joy of jetting a motorcycle carburetor, you know what a fun job this can be. Getting to a base jetting so the motorcycle runs and then adjusting your mixture until you get to optimum performance. Too far one way and the bike bogs and chokes, too far the other way and the thing pings and pops. It’s all part of the motorcycle jetting process. 

Getting the perfect combination for your setup can also take some time and no matter what people may tell you, choosing the right carburetor jets often takes a little guess work. It seems like it should be a simple process, but it usually takes some patience to get everything working perfectly.

Identify and Clean Your Carburetor

The first step is to know exactly what you are working with so you can identify the correct type of carburetor jets and carburetor needle jets you need to complete the job. All carburetors are marked so you can identify them, and most of the time if you look up the specifications for the bike you are working on, they will tell you what carburetor came stock with the bike. 

The next step would be to remove the carburetor and take it apart for inspection. Often it is a good idea to get a carburetor rebuild kit specific to your carburetor, and replace some of the common items. Gaskets, springs, rubber O-rings should be replaced to ensure you are working with a good foundation. 

It’s also important to toughly clean the motorcycle carburetor. If the bike has been sitting it is very likely that the carburetor jets clogged with debris. Get some carburetor cleaner and spray it down.

How do you adjust the main jet on a carburetor?

Next you have to make some determinations. Take a look at manufacturer specifications. This is a good place to start. If you are keeping the bike in its original stock form, you may only need to reinstall the clean carburetor and test it out. If you modified the motorcycle intake you are probably going to need a bigger carburetor main jet in order to compensate for the increase in intake airflow. 

This is the most common jetting scenario. If you are running the bike and you hear pinging or the bike is not making full power at wide open throttle, your mixture is too lean. You need more gas. A rule of thumb is that it is better to run the bike rich instead of too lean. If the bike is run too lean you can cause damage to the motorcycle engine. Better to run the bike a little rich and work backward. 

What to do if my carburetor is too rich or too lean?

For that reason, it’s best to go one carburetor jet higher (bigger) than you think you need. If you test it out and the bike is stumbling, you are probably too rich. Now go down one carburetor jet size, and you should be close. Now you can raise or lower your needle to adjust your needle jet to get the perfect tune. Lower the clip on your needle for a richer mixture, raise the clip on your needle for a leaner mixture.

Lowbrow Customs carries a variety of carburetor jets for sale for Harley Davidson® and Triumph® motorcycles. We have everything you need to help you jet your motorcycle carburetor for optimum performance. We also have a selection of carburetor needle jets and carburetor jet drills to help you clean your original clogged jets as well. When you are ready to jet your motorcycle carburetor, take a look at what Lowbrow Customs has to offer.