Motorcycles come in a variety of styles and sizes. Although they may look very different, they mostly share common component types. For instance, there is no motorcycle ignition system without spark plugs and wires or coils. This article will go through the process of spark plug wire replacement and provide the best spark plug wire sets for all models of Harley Davidson.
Best for Softail (2017> Up) – Accel Wire Set
Best for Softail (Before <2017) – Accel Custom Wire
Best for Dyna (Before <2017) – AIP Dragon Fire
Best for V-Twin – Aokus Spark Plug Wire
Best for Low Riders – Accel 172072
Best OEM – AIP Electronics PWJ191
Types of Spark Plug Wires
1. Magnetic Resistance Wire
This type of spark plug wire is the cheapest resistive wire to produce. The insulation of these wires tends to burn through and short out.
2. Molded Spark Plug Wire
A molded wire is made by using a metal braid that runs along the length of the insulator. There are rings with winding loops at specific intervals that make up the path for the high-energy spark needed by your bike’s cylinders to fire each compression stroke efficiently and adequately.
3. Super Spark Plug Wire or Dyna-Core
This wire has a copper alloy core wound with fiberglass cloth, making it more durable and robust, especially for high RPM use and racing applications.
Different Spark Plug Wires – Best for Harley (All Models)
Key Factors – Harley Spark Plug Wire Buying Guide
Here is what you should think about when buying spark plug wires for your Harley:
All spark plug wires are not created equal, so special care must be taken when buying replacement ones to ensure they work with your motorcycle.
The material used in the insulation of the wire has to withstand high temperatures and provide insulation. Cheaply made insulated wires will corrode your engine components and cause poor performance.
Spark plug wires should be long enough to cover the distance between each of the spark plugs on your bike and any ignition modules or boxes that may get in your way. Too short or too long of a set could leave certain areas unconnected. Or create unnecessary bends that might get worn down over time and affect insulation and voltage transfer.
The order you attach the spark plug wires to your motorcycle’s ignition coils is very important. Failure to follow this process might cause reduced power and, ultimately, engine damage. On most motorcycles, the firing order of cylinders is 1 at the front left, 3 in the middle right, four at the rear right side, and two at the front left.
Number of Spark Plugs
As a general rule of thumb, one wire runs from each spark plug to its corresponding ignition module or box. If you have eight cylinders on your motorcycle, you will need a total of 8 wires (8-plug).
The general rule is that most replacements come with guarantees for 12 months or more against defects and damages, excluding physical damage. Knowing this information can help prevent unnecessary problems later down the road, so it’s worth looking into before you buy.
Top Brands for Ignition Cable for Harley
ACCEL: The ACCEL brand product line includes harnesses and sensors for any vehicle, including Harley Davidson motorcycles.
Aokus: It offers many different ignition cables for numerous motorcycle brands, especially Harley.
JBSporty: The JBSporty brand is of superior quality, offering various styles, colors and fits for Harley motorcycles.
Sumax: It Manufactures top-notch products for different motorcycles, including Harley.
ACDelco: It manufactures high-quality aftermarket automotive parts with renowned expertise and a worldwide presence.
DENSO: The DENSO brand was created in 1949 DENSO also produces ignition cables.
Signs of Bad Spark Plug Wire
1. A rattling noise in the engine
It is often created by an ignition coil shorting out because of wear and tear to its insulation coating.
2. Hard to start when cold due to unburned fuel in the exhaust system
This issue may develop when a spark plug wire runs too close to the exhaust manifold, and the heat begins melting insulation off the wires.
3. The cranking speed
This often occurs when breakage in an ignition coil causes it to short out and increase the voltage in one of the cylinders; thus, that cylinder’s rpm will go up on its own.
4. It Starts fine but stalls as you drive along
When a spark plug wire breaks apart inside its protective covering during engine operation, it can cause this problem by providing insufficient electrical power to an individual cylinder.
Damaged Spark Plug Wire – Testing and Fixing
Not necessarily your spark plug wire goes up to its maximum lifespan. Due to electrical or accidental issues, it may even get damaged sooner. Here is how can you find damaged wire and how can you fix that:
- Turn the key on and put the meter across the two wires from the distributor.
- Remove the distributor cap and rotor
- Remove the two wires from the distributor by twisting them off or sticking a small screwdriver between the wire and the connector.
- Turn the ignition key back to the run position and stick your multimeter probe in between each of the eight plug wire boots.
- If there is no spark, you have a bad wire. You can test this by putting a 4-ohm load on it after taking off all eight wires. If there is no continuity, that wire is bad.
- After you have fixed any problems, install all wires again.
- Turn the key to run, put your meter on each wire as you go around them to make sure you have a good connection.
- After putting your meter on all wires, go around it again to tighten them up.
Can You Test Spark Plug Wire without a Multimeter? How?
You can taste spark plug wire using a battery and a clip lead without the need for a multimeter. This is a quick and easy way to see if your spark plug wire has gone bad. This test will only show you if the wire has a short somewhere in its length.
Can Bad Spark Plug Wires Cause Backfire?
If spark plug wires malfunction, it can cause a ‘spark blow-out’ condition, leading to an engine misfire and even backfire. If left uncorrected, this misfire can ruin an engine pretty quickly.
Spark Plug Wire Lifespan
The average lifespan of a spark plug wire is about 60,000 to 70000 miles. It also depends on the motorcycle’s environment, under what conditions, and how they are maintained.
How to Change Spark Plug Wires? – Installing New Wires on H-D
Step 1 – Remove the distributor cap from your Harley engine with a ratchet.
Step 2 – Take out the old spark plug wires and install new ones. After you get them in, tighten their boots to ensure that the plugs have a solid connection to the wires.
Step 3 – Vacuum out your distributor housing with an air compressor at high velocity to remove any dust build-up.
Step 4 – Clean out the cap before reinstalling it onto your engine. This will result in a smooth fit between the cap and distributor
Step 5 – Look at the old spark plug wires and inspect them for cracks, wear, or any signs that they may be failing. If you spot anything wrong with them, replace the old ones as well.
Replacing Spark Plug without Changing Current Wire
The old wire corrodes and becomes brittle over time since it’s always in contact with the engine’s cylinder head. That heat causes oxidation, which wears it down. If you want to replace your plug without changing your current wire. Clean the old wire with sandpaper or emery cloth to eliminate any corrosion and dirt that might have accumulated.
Protection of Ignition Wire from Heat
You can protect your ignition wire from heat using Spark Plug Wire Protector Shield. It prevents accidental damage from getting the plug wire too hot while allowing full ignition performance. It clips directly over the spark plug and sticks to itself using a special adhesive, creating a sleeve that insulates the spark plug wires from engine heat and oil splash.
A spark plug wire is an electrical system that uses a conductor to pass electrical current from the battery to your engine’s spark plugs. The wire itself becomes less conductive and can cause major problems when it wears down or becomes broken. Spark Plug Wire helps reduce misfires in engines and will help keep the engine running smoothly for longer periods. Replacing the wire is a simple process if you follow the tips listed above.
Last update on 2022-06-20 / Images from Amazon Product Advertising API