You’ve dreamt of owning a Harley Davidson for the longest time, and now you finally have a Hog. You love every little thing about your bike. It’s tempting to go to a professional mechanic at the first sign of trouble. You want your bike to have the best care possible. However, some issues are easy to fix on your own.
One example? Adjusting the idle on your fuel-injected Harley Davidson.
The idle speed refers to how fast the bike moves after releasing the brakes on a running engine. After continuous usage, your Harley Davidson may need an idle adjustment.
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How to Adjust the Idle Screw on a Fuel-Injected Harley
If you have a fuel-injected Harley Davidson, you can adjust the idle with a few simple tools. Twisting the little knob that juts out of the engine compartment on the right or left side of the bike allows you to adjust the idle speed. Let us look at how that is done.
Know Your Bike’s RPM
To identify and access your Harley’s idle screw, you must first understand your Harley’s recommended Revolutions Per Minute (RPM). Go through your bike’s manual to understand the average RPM of your Harley. The perfect setting is between 700 and 1,000 RPM.
A lot of bikes come with a tachometer to help you pinpoint the RPM. A tachometer is a compass-like device that helps you to understand the speed at which your bike is idling. This will allow you to check if you’re in the ideal RPM range. If the tachometer shows that the RPM falls within the recommended range for your bike, then adjusting the idle screw is unnecessary. But, if it isn’t in the ideal range, then you know that you have to adjust the screw. You should be able to control the bike once it picks up speed without placing your feet on the ground.
Unfortunately, if you don’t have a tachometer, you will have to determine the RPM by ear. You should hear a steady whir when the bike is idling. If you hear a high-pitched whir, then you know you have a problem. If the idle setting is too high, your bike might backfire spectacularly.
Once you’ve determined the RPM, the next step is to locate the carburetor on the bike.
Locate the Carburetor
Usually, the carburetor is located right next to the engine or just below it. It is a long and blocky component that has a circular opening in the middle. I advise you to go through your bike’s printed manual to locate the carburetor. This large piece of metal is located differently on bikes and may not be apparent to the inexperienced eye.
The carburetor is responsible for mixing gas and air to drive your engine, making it an essential component in your Harley. It also stabilizes the idle speed of the bike through the idle screw.
Both the carburetor and idle screw have interlinked tasks. The carburetor converts gas and air to power your bike. Meanwhile, the idle screw regulates the amount of air and gas entering the bike while it is idling. Once you find the carburetor, it’s easy to locate the idle screw.
Locate the Idle Screw
The idle screw is located on either the left or right side of the bike. It is bolted to the end of a small gas canister under the carburetor.
You can see this screw inside a small spring in the float bowl, which is connected to a coil. This coil can be placed either vertically or horizontally on the carburetor. Remember, the idle screw can be unfastened using a 12-inch Phillips flat-headed screwdriver.
Remove Anything That Blocks Access to the Idle Screw
Sometimes, a piece of metal can obscure your view of the idle screw. Remove that part from the bike temporarily, but don’t throw it away. Put them aside so you can finish adjusting the idle screw. Use a socket wrench or an Allen wrench to loosen the screws that keep the panel in place. Then, smoothly lift the panel from the bike.
Remember, some bikes don’t have bolts on these panels. Instead, they have clips that secure them to the bike frame. To lift the panel, all you have to do is apply pressure at the edges of the clips.
Stabilize the Engine
Before we get into adjusting the idle screw, switch on your bike and let it run for a minute or so. This allows the engine to warm up and stabilizes the bike. You can adjust the idle screw when it isn’t running, but it’s much safer to do it while the bike engine is on neutral. You want the engine to change gears slowly while fuel’s coursing through the bike.
If it’s winter or you’re in a cold place where the temperature is below 40 degrees Fahrenheit, keep the bike running for at least 15 minutes. Warming up your engine helps improve the engine’s performance.
A lot of bikes have a “cold idle setting” that controls the idle speed of your bike as the engine is warming up.
Adjust the Screw
Let’s say you’ve determined the problem, and now you have to increase the idle speed. What do you do? Simply turn the screw clockwise for a higher setting. If you see that your idle speed is considerably low, turn the screw clockwise using a Phillips screwdriver.
Now, this is useful if your screw is horizontally placed in the coil. If it’s vertically placed, then you will need to turn the screw counterclockwise. If you have any minor adjustments, turn the screw once or twice. But, if you think it requires major changes, then turn it in at least four to five times. You usually won’t need to go that far.
You can turn the screw by hand, but I recommend using a screwdriver because that’s safer and easier.
Unfasten the Screw
You won’t always have to tighten the idle screw. You may have to loosen it as well. Instead of turning the screw clockwise, turn it counterclockwise. Do this to reduce the speed of the idle. Keep turning the screw until you reach your desired idle speed or the idling engine sounds right. You most likely won’t need to turn the screw more than three to four times.
Use the Tachometer Again
After doing all this, you will need to use your tachometer again. You need to track the changes you started to look for the idle screw. Again, the changes you make should fall within the ideal RPM range. If they don’t, then tweak the screw some more until you get the desired results.
Go for a Test Ride
Once you’ve made the changes you need, shut the bike off. Then, turn on the ignition again for a test ride. Lift the kickstand and sit on the bike. Release the brake and let the motorcycle idle for at least five to seven feet. This way, you’ll be able to observe if the changes you’ve made to your machine are effective. It also lets you see whether you need to make more adjustments.
You must remember that a fuel-injected Harley Davidson will idle higher than most bikes. The bike may idle high after adjusting the screw. Do not take this as a sign to re-adjust the screws. Harleys tend to idle higher so that their engines will warm up faster. Give it a few minutes, then check if the adjustments made are all right using the tachometer.
It’s possible that the idle still feels a little low or high. That’s alright; you don’t have to get the perfect settings on your first try. Simply make further adjustments to your idle screw. Soon, your bike will be good to go.
Harley Davidson Idling Issues
Fuel-injected Harleys and other bikes tend to have more problems with their idle speed. These problems are usually caused by a serious mechanical problem or an unclean throttle. If the latter is the reason for your idle speed problem, you need to clean your bike thoroughly. To prevent this and other mechanical issues, cleaning and maintaining your motorcycle should be done regularly.
What if you’ve cleaned the bike and the idle is still not working properly? Then you probably have a serious problem on your hands. This could be a sign of defects in the speed sensors, a vacuum leak, or engine trouble.
When this happens, reach out to a professional mechanic for help.
Conclusion
Does your Harley’s engine sound off while idling? This may seem like a challenging obstacle to overcome, but it isn’t. Adjusting your idle screw is neither time-consuming nor difficult, even for non-technical people. A bike cannot take care of itself. It falls upon you to lavish your bike with the weekly washes, monthly checkups, and tune-ups it needs to run smoothly.
You already spent all this money on purchasing the bike of your dreams. Make sure you protect your investment by keeping it in tip-top shape. Then you can ride your Harley Davidson for years to come.
