Best Spark Plugs for Harley Davidson – Buying Guider Helpful (Update 2022)
Is your Harley Davidson engine experiencing a lot of stalls or backfires? Does your motorbike seem to be rougher when running than it used to be? This might be the ideal time to replace your motorbike’s spark plugs. The main benefit of doing this is to improve your engine’s performance, save money on fuel and also keep maintenance and service at a minimum cost. This review will give you some insight on the best spark plugs for Harley Davidson so that you can find it easy to choose the best plug when you want to replace your Harley Davidson’s spark plugs.
The spark plugs play a major role in running the engine. The plugs are usually a pair of electrodes which normally produce a high voltage spark necessary to ignite the fuel which eventually powers the engine and get the wheels running. The sparks sent between the plugs each time erodes a tiny amount of metal, and with time, this might result in the enlargement of the gap between them.
When the gap between the two metal electrodes of the plug is too large, the efficiency of the sparking reduces. This results in rough engines, misfires and also excessive gas consumption. This is the time you are required to replace your motorbike’s spark plug. This type of maintenance is easy, and you can do it yourself.
Types of spark plugs

There are four types of spark plugs based on the material used to make them. They are:
- Copper core plugs-These are the cheapest plugs, and they are the best for engines with higher temperatures
- Iridium plugs-These plugs work best for lower temperature engines though their conductivity is not that good
- Platinum plugs-These plugs are of better quality when compared to iridium plugs. They serve for between 40000 to 60000 miles before they are exhausted
- The double platinum-This plug is of the highest quality in terms of services. It is also the most expensive type
How to Choose the Spark Plug for Harley Davidson?

- Model of your Harley Davidson motorbike
Depending on the model of your Harley Davidson motorbike, there are a number of factors that affect the type of spark plug to choose. You should be able to choose the one that is best for your engine. The plugs differ in plug diameter and reach, the nose of the insulator projection and the plug’s conical shape.
- Size of the gap between the electrodes
The gap of different spark plugs also varies in size. They differ in the gap size between the electrodes. This is because different Harley Davidson engines also require different sizes of the gap between the electrodes in the spark plugs to be able to operate efficiently. When buying the spark plugs, you have to consider that some can be manually adjusted before fixing while some come when they have been adjusted already.
- Fuel system of the motorbike
You also need to consider the fuel system of your motorbike. If your motorbike’s engine is fuel injected, there is a need for you to know whether your motorbike has a multi-body or throttle body injection. This will help you in knowing the best plug to buy for it.
- Engine displacement
Consider also the engine displacement. This is the room that is available when the piston system is at its lowest point while in operation. Usually the capacity of the air and the fuel that the cylinders in the engine can hold increases with the increase in the size of displacement so you must as well consider that before buying a spark plug for it.
- Brand of your motorbike
The brand and make of your motorbike really matter. Like in our case the make of the motorbike is Harley Davidson. This is important because different motorbike models require a particular type of spark plugs.
Considering the above factors will help you in choosing the best spark plug that is compatible with your motorbike’s engine.
The Importance of Spark Plugs in Your Harley Davidson Engine
High-quality spark plugs ensure that your motorbike’s engine gives out a top performance and increases the rate of efficiency. If you don’t replace your engine’s spark plug in time, your motorbike might experience misfire which is very hectic.
The spark plugs also help in fuel consumption, and if you do not replace them in time, your motorbike might become less fuel efficient. This might also lead to problems with your exhaust emissions over time.
If you want to avoid these problems and most probably save your engine from damages caused by misfire, make sure you use the best spark plug during the replacement of the used one.
Facts about Mechanical Work Involved
Replacing, checking or cleaning spark plugs is one of the simplest mechanical works one can do by himself on his motorbike or machine. This kind of engine maintenance can be done by oneself at home hence saving the expense that you may incur by calling a mechanic. This work does not require much mechanical knowledge, but it only takes a bit of your patience and willingness to learn and know. If you learn to do it, you will always ensure that you perfectly prepare it in your motorbike for the best engine performance.
Top 3 Best Spark Plugs for Harley Davidson Reviews 2021-2022
Product Name | Score | Price | Our Rating | Reviews |
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* Below, you'll find our more detailed reviews, but you can also click the links above to see current prices or read customer reviews on Amazon.
1. NGK Iridium IX Spark Plugs

Via Amazon.com
Overview
This plug has great performance since it is made using the ultimate plug technology from the leading industries. The plug is 25% smaller than the platinum electrode. Its ultra-small electrode diameter center helps it to reduce the voltage requirement which thus extends the life of the ignition system.
The plug is designed with the new metal shell plating which enhances it with anticorrosion qualities. The plug is a quarter size of the conventional nickel electrode, and it usually comes already pre-gapped.
Features
- The product comes when pre-gapped
- Has the new metal shell plating which gives it enhanced anticorrosion qualities
- The plug has an ultra-small diameter electrode center which reduces the voltage requirements hence extending the life of the ignition system
- The iridium electrode of the plug is 25% smaller than the platinum electrode
- The electrode of the plug is quarter the size of the conventional nickel electrode
Pros
- The ultimate spark plug technology that they are made of make them serve efficiently
- The fact that the product comes when pre-gapped makes it easy to fix or to adjust before fixing
- The new metal shell which the plug is made of enhances it with the anticorrosion qualities. Hence it serves for a longer time
- The plug has the ultra-small diameter electrode center which reduces the voltage requirements hence extending the life of the ignition system
- The high temperatures in the plugs allow the electrode to burn off any residue which might have built up making them have a property of efficient self-cleaning
Cons
- The plugs seem to be small in electrode diameter making them not to be compatible with other motorbike models
- The factory gap may require manual adjustment before they are fixed
2. NGK # 6046 Iridium Spark Plug
This plug is constructed to be exceptionally durable. The product improves the response of your engine throttle and a stable spark in every startup. The plug is designed to have great anti-seizing qualities and has a metal plating which resists the corrosion. The iridium tip that the plug is made of offers great performance.
Features
- The plug is designed with a long insulator nose which keeps the plug from fouling hence increasing its efficiency
- The iridium has an extreme melting point which makes the plug durable enough for even the high-temperature engines
- A ribbed insulator which prevents the flash over
- The metal plate is designed in a way that they resist corrosion hence increasing the plug life
- Made iridium alloy material

Via Amazon.com
Pros
- It is designed to be resistant to oxidation and wear even at high temperatures of the engine when in operation hence making them always last longer
- Has a long insulator nose which keeps the plug from fouling
- The iridium has an extreme melting point which makes the plug durable enough for even the high-temperature engines
- Has a ribbed insulator which prevents the flash over.
- The metal plate is designed in a way that they resist corrosion hence increasing the plug life
- The iridium tip of the plug allows fast acceleration hence making it work perfectly
Cons
- May not perform well in other motorbike’s like German motorbikes
- May require manual gapping before they are fixed
3. NGK (6046) DCPRR7EIX Iridium IX Spark Plug

Via Amazon.com
This product offers great performance as it is designed with exceptional ignitability. The plug is designed with improved throttle response as well as super anti-fouling. It has super fine welded iridium tip of 0.6mm which ensures high durability of the plug as well as consistently stable sparking.
The plug is also equipped with tampered ground electrode which minimizes the electrode quenching effect. The insulator nose is designed to be long hence preventing fouling, and the ribs on the insulator are also corrugated to prevent flashover.
Features
- The trivalent metal plated plug is anti-corrosive which makes it last longer. This property also makes it to be anti-seizing
- The plug is made of iridium alloy which has an extremely high melting point. This makes the product to have high melting point hence can be used in high power engines which operate at high temperatures. The product also resists electrical wear
- Insulator nose of the spark plug is usually designed to be longer hence preventing fouling making the plug to be efficient
- The spark plug also has corrugated ribs on the insulator which prevents flashover from occurring
- It has tripled gasket seal which eliminates combustion gas leakages
- The tapered ground electrode of the plug also minimizes the electrical quenching effect
Pros
- Insulator nose of the spark plug is usually designed to be longer hence preventing fouling making the plug to be efficient
- The tapered ground electrode of the plug also minimizes the electrical quenching effect hence making the plug to work efficiently
- The spark plug also has corrugated ribs on the insulator which prevents flashover from occurring
- It has tripled gasket seal which eliminates combustion gas leakages
- The trivalent metal plated plug is anti-corrosion which makes it last longer. This property also makes it to be anti-seizing.
- The plug is made of iridium alloy which has an extremely high melting point. This makes the product to have a high melting point hence can be used in high power engines which operate at high temperatures. The product also resists electrical wear.
- This spark plug is designed to offer great ignitability and improved throttle response which makes it be perfect
Cons
- The plug may need manual gaping before fixing it
Wrapping up
Most people always take pride in owning a Harley Davidson motorbike. Therefore, it is always important to take care of these machines each and every time. You must ensure that you use the very best plugs to make sure that they offer you the best performance.
You should make sure that the plug that you buy for your machine is the best to improve the engine’s performance every time. When you want to buy a new plug, I would advise you to go for NGK (6046) DCPRR7EIX Iridium IX Spark Plug. This plug offers excellent performance for Harley Davidson hence it is the best one for the engine.
Please leave a comment in the comment’s section below and post any questions that you might need to be addressed. Please share this article with other Harley Davidson motorbike owners.