Harley Davidson Cv Carburetor Troubleshooting

If you are a Harley Davidson owner, then you know that the CV carburetor is a vital part of your bike. But what do you do when it starts to give you trouble? Harley Davidson CV carburetor troubleshooting can be done by checking the air filter. A dirty air filter can cause all sorts of problems, including a loss of power and an erratic idle.

This blog post will help you with the causes of CV carburetor problems, as well as will provide some simple steps outlined here, you can quickly and easily troubleshoot any problems that may arise with your CV carburetor.

What are the causes of CV carburetor problems?

There are several potential causes of CV carburetor problems, and it is important to identify the root cause to find the best solution. Some of the most common causes of CV carburetor problems include:

1. Dirty or contaminated fuel

Fuel contamination is one of the most common causes of CV carburetor problems. Over time, dirt and debris can build up in the fuel lines and eventually make their way into the carburetor. This can cause a variety of problems, including decreased performance, engine hesitation, and stalling

Furthermore, fuel contamination can also lead to corrosion and other damage to the carburetor itself. As you know that fuel is necessary for the proper working of Harley Davidson and if it gets contaminated then it will surely give you problems.

2. Clogged idle mixture circuit

The CV carburetor has a series of tiny passages connecting the mixture screw, pilot jet, and air intake jet located on the side of the front of the carburetor. The idle mixture circuit is responsible for supplying the carburetor with the correct mixture of fuel and air when the engine is idling

If this circuit becomes clogged, it will result in a lean mixture at idle, which can cause problems like lean popping and backfire, and engine hesitations. Because when the engine is idling, it needs the correct mixture of fuel and air and if it doesn’t get that then it will stall. As a result, the circuit gets clogged.

3. Faulty float needle

The float needle is located in the float bowl and is responsible for regulating the flow of fuel into the carburetor. Over time, the float needle can become worn or damaged, which can cause fuel to leak into the carburetor. This may result in several issues, including a lean combination. A bad float needle can also lead to the carburetor overflowing, which could harm other components of the bike and make a mess. Therefore, it is crucial to regularly inspect the float needle and replace it as needed.

4. Vacuum Leak

A vacuum leak is another potential cause of CV carburetor problems. The importance of a perfect seal where the carburetor spigot press fits into the intake manifold cannot be overstated. If there is the smallest vacuum leak at this point, it will have a major impact on the carburetor function. In addition, this leakage can also cause the engine to stall. So, it is important to get this fixed as soon as possible.

How to troubleshoot Harley Davidson CV Carburetor problems?

As we know, the CV carburetor is located under the carburetor cover. So, if you find that your Harley Davidson is having problems with the CV carburetor, then you should follow these methods to troubleshoot CV Carburetor.

1. Fix the vacuum leaks

One of the first things that you need to do is fix the vacuum leaks. You should apply a small amount of silicone grease to the O-ring that is located on the spigot of the carburetor. 

Make sure the carburetor presses firmly into the intake manifold. If there is still a vacuum leak, you may need to replace the carburetor gasket. To test the vacuum leak use a propane torch and hold the flame next to the carburetor while the engine is idling. If you hear the engine speed change, then you know there is a vacuum leak.

After that, you need to reinstall the carburetor and start the engine. If the engine idle is still not stable, you may need to adjust the carburetor mixture screws.

2. Check the float level

Another thing that you need to do is to check the float level. The float level controls the fuel level in the float bowl. If the fuel level is too high, it can cause fuel to leak into the carburetor and eventually into the engine. This can cause engine stalling or a lean mixture. 

To check the float level, you will need to remove the carburetor and look inside the float bowl. The fuel level should be about 1/4 inch below the bottom of the carburetor body. If the fuel level is higher than that, you will need to adjust the float level.

3. Check the float needle

To check the float needle, you will need to remove the carburetor and look inside the float bowl. This will allow you to see if the float needle is seated properly. If it is not, it can cause fuel to leak into the carburetor and eventually into the engine. This can cause engine stalling or a lean mixture. To fix this, you will need to adjust the float needle.

4. Check the gas cap venting

As we mentioned pressure inside the gasoline tank may build up if the gas cap vent is malfunctioning. So just look at the gas cap to see if the vent is clear. You can also try removing the gas cap and see if the engine idles changes. If it does, then you know the gas cap vent is not working properly.

How to clean Harley Davidson CV Carburetor?

If you own a Harley Davidson, chances are you will eventually need to clean your CV carburetor. While this is not a difficult task, it is important to follow the proper steps to ensure that your carburetor is cleaned properly and that you do not damage any of the parts. Here is a step-by-step guide on how to clean a Harley Davidson CV carburetor.

1. Remove the gas tank and disconnect the fuel line from the carburetor.

2. After the fuel line is disconnected, remove the four bolts that hold the carburetor in place.

3. Once the carburetor is removed, take it apart and remove the float bowl.

4. Use a carburetor cleaner to clean all of the parts of the carburetor.

5. Once the carburetor is clean, reassemble it and reinstall it on the motorcycle.

6. Reconnect the fuel line and reinstall the gas tank.

7. Start the motorcycle and let it idle for a few minutes to ensure that the carburetor is working properly.

8. If the carburetor is not working properly, consult a Harley Davidson dealer or mechanic for further assistance.

Cv Carburetor Diagram:


Final Verdict

Harley CV carburetor issues can be caused by several different things. Some of these are gas cap venting, idle circuit channels, float level, float needle, vacuum leaks, and Harley vacuum slides. You will need to take off the carburetor and rebuild it to diagnose these problems. 

You can then clean the idle circuit pathways after that. Additionally, you want to replace the Harley vacuum slide and check the float level. You might need to take your Harley Davidson to a technician if you’ve tried all of these fixes and the CV carburetor is still giving you trouble.

In this guide, we have discussed some of the most common Harley CV carburetor issues and how to troubleshoot them. We hope that this guide will help you fix your Harley Davidson.

About David Riedel

I am David Riedel founder of Bikerwhizz, I'm a technician at Keystone Harley Davidson with more than 10 years of industry experience. I’m here to help you solve motorbike problems, customizations, tweaks, and easy fixes to enjoy your rides more.

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