Why is my CV carb not working on my Harley?
Again it should be emphasized, the #1 cause of carburetor related problems on a Harley or other V-Twin motorcycle is VACUUM LEAKS. The CV carb is dependent upon vacuum to function properly. 2) Check that the Needle Jet (nozzle) is installed correctly.
Where is the throttle cable on a CV carb?
The slide on a conventional carb is directly connected to the throttle cable. Twist the throttle grip and the slide is raised in the venturi. On a CV carb the throttle cable is connected to a butterfly valve that varies the volume through the venturi.
When to tune a Harley Davidson CV carburetor?
These tuning steps apply to all Harley CV carbs from 1989 to present that use the CV 40mm style Harley Davidson carburetor but also apply to the CVK40 found on other models. Always start with a fresh set of spark plugs when tuning. The carburetor will need to be removed from the manifold so refer to your factory shop manual for this procedure.
What causes CV carburetor to not spray fuel?
4) Accelerator pump weak or not spraying. Check that fuel sprays from the accelerator pump nozzle when rolling on the throttle (test with engine off). The accelerator pump diaphragm will wear or crack over time or if left to sit in a fuel filled CV carburetor for extended periods and will eventually deteriorate.
Can a CV carb be mounted on a Shovelhead?
This first article will address modifying the manifold to accept a CV carb, while the second article (next month) will illustrate the fabrication and design used to securely mount the carb to a shovelhead. I’m pretty much sold on retro fitting CV carburetors on shovel and pan motors…
Again it should be emphasized, the #1 cause of carburetor related problems on a Harley or other V-Twin motorcycle is VACUUM LEAKS. The CV carb is dependent upon vacuum to function properly. 2) Check that the Needle Jet (nozzle) is installed correctly.
How do you upgrade a CV carburetor on a Harley Davidson?
Step 1 – Unbolt the old carburetor from the manifold. Disconnect the fuel line and vacuum hoses. If the original dual cable setup is to be reused label them for reinstalling on the CV carburetor. Step 2 – Loosely place the flange adapter on the carb and align with the manifold bolts.
4) Accelerator pump weak or not spraying. Check that fuel sprays from the accelerator pump nozzle when rolling on the throttle (test with engine off). The accelerator pump diaphragm will wear or crack over time or if left to sit in a fuel filled CV carburetor for extended periods and will eventually deteriorate.
Can a Harley Davidson CARB be pulled away from the manifold?
A simple “Top” and “Bottom” should suffice when tagging each cable. Now that you have enough slack in the cables you can pull the carburetor away from the manifold. A Harley carb is only held to the manifold with a slip fit rubber manifold boot.
How many turns does a carburetor need in a Harley Davidson?
If the engine responds quickly with a smooth blast and no backfiring through the carburetor, you have your idle mixture right. If backfiring occurs through the carburetor then adjust the idle mixture screw out another 1/8 turn. Normally, the mixture screw should only require 2 to 3 turns.
What kind of carburetor does a 1989 Harley Davidson use?
This simple procedure is a great Harley tech tip that applies to all Harley carbs from 1989 to present that use the CV style Harley Davidson carburetor. Earlier models equipped with the older butterfly style carbs (pre-89 Evo’s, Shovelheads, Pans, and Ironheads) are excellent candidates for upgrading to a modern Harley carburetor.
Who is the best guy to troubleshoot a Harley Davidson carburetor?
Bob’s at the bench with your Harley carburetor troubleshooting questions. He gives his suggestions on where to start when you are having fuel delivery issues. He also gets into other issues that might be the issue for a “stumbling” motorcycle. Watch how to rebuild your carburetor with our Carburetor Rebuild Class.
What’s the top speed of a Harley Davidson Fat Boy?
MCycle mentions that the bike has a top speed of 91.96 MPH and that it weighs 657 lbs. The Fat Boy is perhaps the most car-like of any Bike that we can think of. The suspension is so good you could probably ride directly over an open manhole and never notice.
When to start a Harley Davidson CV carburetor?
The mixture screw or EZ-Just is the key to proper tuning. These tuning steps apply to all Harley CV carbs from 1989 to present that use the CV 40mm style Harley Davidson carburetor but also apply to the CVK40 found on other models. Always start with a fresh set of spark plugs when tuning.
Do you have to remove the carburetor when tuning a Harley?
Always start with a fresh set of spark plugs when tuning. The carburetor will need to be removed from the manifold so refer to your factory shop manual for this procedure. With the carburetor removed, place upside down on a sturdy work surface.
How to troubleshoot no fuel going to a carburetor?
Remove and check all fuel filters located in the fuel line and in the carburetor. Replace any and all filters that can not be confirmed good or have not been changed recently. Inspect the fuel lines for leaks or kinks that might interfere with fuel flow.
Why does the carburetor open when the vacuum drops?
The throttle opens wider and the intake vacuum drops as the engine load increases. It reduces the fuel flow causing the fuel mixture to go lean. There is a vacuum-sensing mechanism within the power valve of the carburetor, which opens to increase fuel intake when vacuum drops.
How to correct a carb jetting motorcycle backfire?
Start the motorcycle cold with the choke on and see if there are any signs that it is loading up with fuel. Decrease the choke to lessen the fuel. Allow the bike to warm up to riding temperature, about two minutes. How does the bike respond to a standing throttle range? Is it smooth in the low RPM range from idle to about 1200?
What are the symptoms of rich carb settings on a motorcycle?
Rich Reduced Power – It has less power but seems to be OK and runs. Reduced Fuel Mileage – Your using more fuel per cycle so your mileage becomes worse. Rough Idle – Combustion takes a just a bit longer with more fuel and at lower RPM’s the engine can idle rough.
What should I do before tuning my CV carburetor?
The air cleaner assembly must be installed prior to starting the engine, not only to hold the carburetor in place but to prevent having the carburetor backfire in toward you while tuning. Start the engine as normal and bring up to operating temperature prior to fine tuning. Let the bike idle for no more than 5 minutes.
Why is my Harley CV carburetor stalling after tuning?
Hesitation or stalling can sometimes occur after tuning or rebuilding your Harley CV carburetor or if your Harley carb has not been maintained. The following are common issues sometimes encountered after tuning or rebuilding a Harley CV carburetor.
Can a carb run well on a cold engine?
Carbs are tuned to run well on a hot engine, which should make sense… if you want to go ride your bike all day, it’s probably going to spend a lot more time hot than cold. The problem, of course, is that the carb then is not set up to deal with engines at lower temperature.