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In days gone by, motorcycle spark plugs would wear out so quickly that you would find yourself going through them at a rapid rate. But advancements in technology have helped this issue, making them much more reliable and long-lasting. Even though you don’t need to worry about replacing them as often as you once did, it is still important that you choose one which is going to be beneficial to the operation of your bike. You also need to ensure that you pick a spark plug which is fully compatible with your vehicle.
So, let’s run through just a few of the best motorcycle spark plugs in front of you to help in your task of making a more informed decision.
The Best Motorcycle Spark Plug
First up, we have this pair of spark plugs from a industry leading manufacturer NGK, which come already pre-gapped. You may notice straight away that the diameter is ultra-small. It is designed this way to reduce voltage requirement and extend the life of your ignition system. In fact, the iridium electrode is 25% smaller than even a platinum electrode.
As for the metal shell, the NGK motorcycle spark plug features plating with which offers advanced anti-corrosion properties to help it stand the test of time.
Gain up to 3HP
Pre-gapped spark plugs
Highly small diameter center
Good-quality anti-corrosion properties
- Weight1.44 ounces
DENSO can boast being the first manufacturer to use iridium – something which has become standard for many spark plug makers these days. You will often find them in luxury vehicles, which is testament to their quality.
During their manufacture, a sophisticated 360-degree laser-wielding process has bee utilized. They rank highly on many customers’ reliability scale, and they can really help if your bike is exhibiting any bad spark plug signs.
Four plugs included
First brand to utilize iridium
High-quality reliability and performance
- Weight0.16 ounces
Carbon deposits are the scourge of the car engine, and these spark plugs help to get rid of these performance limiting substances. One of these spark plugs can provide a healthy power boost to your engine. Not only this, but they also promise enhanced fuel efficiency as well. And if you are at all concerned about the environment, they can also help to drastically reduce potential emissions. On top of all this, a limited lifetime warranty is included.
Provides smoother acceleration and idle
Increased power and fuel efficiency
Longer plug life
Limited lifetime warranty
- BrandE3 Spark Plugs
- Weight1.92 ounces
If you are looking for multiple spark plugs, you have a pack of eight here which should keep you going for some time! Iridium is used in the making of these plugs, which has been shown to offer a host of benefits including quicker acceleration, smoother performance, and improved cold starting. It also provides wear resistance and durability. Not only is this product highly-rated, but it is also competitively priced at the same time.
Pack of 8 spark plugs
Iridium offers a host of advantages
Long electrode life
One-piece suppressor seal blocks radio frequencies
- Weight12.8 ounces
Using plasma-assisted combustion, this spark plug offers numerous different advantages to your motorcycle engine including increased horsepower and improved throttle response. You can gain as much as 7 horsepower and 9 ft-lbs of torque. Other advantages that you can expect to receive are better miles per gallon (MPG), a smoother idle, and lower emissions. Since it burns fuel more quickly and efficiently, it improves engine performance.
Uses plasma assisted combustion technology
Created with support from a US Department of Energy laboratory
- Weight2.4 ounces
This 4-pack of spark plugs has the advantage of being highly affordable for people on a tight budget. The strong copper core offers a big spark, as well as improved heat dissipation and conductivity. It also has a longer insulator nose which prevents fouling. To prevent combustion gas leakage, there is a triple gasket. The electrodes are dual ground to provide a more consistent spark.
Solid copper core at the heart
Dual ground electrodes
Triple gasket seal
- Weight8.3 ounces
The last product on our list is this one from Autolite with a copper-glass seal to bond together many of the key components in a way which is leak-proof. The copper core electrode is specially designed to comfortably deal with all sorts of different conditions. A few of the advantages that you can count on include quick starts, decent fuel economy, and smooth acceleration.
Copper-glass seal provides tight seal
Resistor reduces radio frequency interference (RFI)
Full copper core electrode for high-quality performance
- Weight1.6 ounces
Best Motorcycle Spark Plug Buying Guide
Now that we have discussed our top seven picks of motorcycle spark plugs, the next section is all about answering other questions you may have, whether you are looking for a Harley Davidson spark plug or a dirt bike spark plug. First, we will look at what to prioritize when buying motorcycle spark plugs, before listing the different types which are commonly available. We will then look closer at a couple of the top brands on the market. We then have our frequently asked questions (FAQ) section, and a recap of our number one pick of the products discussed.
What to Look for in Motorcycle Spark Plugs
You may still feel like you need a little more information in choosing a motorcycle spark plug. Well, in the following section, we will offer you an overview of a few of the key features which you need to stay vigilant for. Most of these relate to making sure that you match up the plug with your vehicle. Otherwise, you could end up with a product which is entirely incompatible for your needs, and this could lead you to need an early replacement.
- The Size
Motorcycles come in different shapes and sizes – as do spark plugs. The size is measured by the diameter of the threaded area. If this is wrong, you won’t be able to tighten it as needed. Vehicles differ in their engine design, so you need to choose a plug which will work well with your bike. You should check your owner’s manual for more information on information on the recommended plug. If you choose one which is the incorrect diameter, you are not going to be able to tighten it in place as needed. Or you may even damage the cylinder head by destroying the threading. So, if you are looking for the best spark plugs for a Harley Davidson, make sure that you clarify that it is compatible.
- Electrode Gap
Another specification to pay attention to is the electrode gap. This term refers to the distance between the center electrode and ground electrode. The latter is always at 0 volts. When the former reaches the correct voltage, it will release an electrical discharge as a spark, which will ignite the fuel and move the pistons. This needs to be especially precise or it can lead to a whole host of problems for your vehicle including a high number of misfires, power loss, bad fuel economy, and reduced lifespan. Remember, this figure needs to be precise within hundredths of an inch.
- Heat Range
Spark plugs come in different heat ranges (we will go into more detail about this a little bit later). Make sure to check your owner’s manual so you know which one to go for. All heat ranges are displayed in numerical terms with the lower numbers being hotter and the higher ones being cooler. If your bike has a modified engine, you should consult with an expert who know a lot about performance modifications.
All of the points we have discussed so far are in some way related to compatibility, but it is worth giving this point its own separate section as well. Before you can buy the right spark plug, you need information like the make and model of the vehicle, the engine type, the kind of fuel system, and the part number. The more information you have, the more likely it is that you will make a wise and informed choice when it comes to spark plugs.
Whenever you are buying any product for your motorbike, you want to be sure of its quality. Firstly, you want it to stand the test of time. And secondly, you don’t want it to do anything harmful to your bike which could have otherwise been avoided. One way that you can be surer of the quality is by checking the brand and what sort of credentials it offers. Also, you could look at previous customer reviews to see what they have said about the product.
The right spark plug should offer a decent amount of functionality for your car engine. Assess your different options closely to determine what sort of positive features they can all offer. It is easier if the product lists a lot of information beforehand. This way, you can compare and contrast the different options available to you.
Types of Motorcycle Spark Plugs
Motorcycle spark plugs vary in various ways. So, let’s start by looking at each of the top three types of electrodes in more detail, as well as offering a rundown of some of the main pros and cons. We will then move onto some of the other major variations which you can expect.
- Type of Electrode
First up, we have copper electrodes. This design is the most old-fashioned, and it is one which doesn’t exist particularly widely anymore. Essentially, it features a solid copper core with a nickel alloy coating. Even though you don’t find them in modern bikes, they still may be suitable for bikes made before 1980 with low-voltage ignition systems. However, be wary that cheaper models made of copper tend to collect deposits more quickly, which can end up degrading their functioning.
Platinum electrodes electrode features a copper core with a platinum disc welded to the central electrode. Platinum is a hard material which is designed to last for a long period of time. Since it will run hotter than a copper plug, it will lessen the deposits which build up. This tends to be a much more standard option in the world of modern bikes. You can also get double platinum plugs, which have discs on both electrodes.
Finally, you have the electrodes with a copper core and an iridium tip rather than a platinum one. Iridium is around 25% harder than platinum, and ever since it was introduced into the market, it has become a highly popular choice. It is celebrated for its long-lasting properties, but it is also at the premium end of the price scale.
- Double-Grounded or Single-Grounded
The next variation to discuss is all about whether you choose double-grounded or single-grounded plug. Next to the center electrode will be one or more ground electrodes. If you have more, this will help to extend the life of the spark plug. If one wears out over time, you still have more to fall back on. On the downside, the use of fuel may end up being less efficient.
- Fixed Gap or Adjustable Gap
Some spark plugs have a fixed gap, which means that it stays rigidly in place and you don’t have the freedom to adjust them as you would like. Otherwise, you have plugs which are adjustable, which allow you to alter them in accordance with the gap gauge medallion. Ultimately, you need to consider whether adjustment is a worthwhile feature which you would like or not.
- Spark Plug Reach
A specification which we haven’t discussed so far in this blog post is the reach of the spark plug. This refers to how far it projects into the combustion chamber. The number of threads that a spark plug has is a good indication of its reach. If the plug fails to protrude enough into the combustion chamber, you will not get good combustion. But if it protrudes too deep, the pistons may damage it while the engine operates. Alternatively, pre-ignition may occur, which will cause the fuel to ignite too early. Again, this can lead to a loss of power.
Spark Plug Brands
If you have never thought in great detail about different spark plug brands, this next section will enlighten you about a few of the different options that you have. If you select a brand which is well-known for creating high-quality, reliable products, you have a better idea of what you are buying. Also, there will be a lot more information readily available including product reviews etc.
This Japanese manufacturer has been around since the 1930s and is a very well-known and widely respected option. They sell well, are renowned for their regular innovations, and have been adopted widely as an OEM brand.
Another Japanese brand, Denso started as part of the Toyota brand, before splitting off to go independent. The brand is well-known in the industry, and it is often used as OEM equipment including compressors, starters, and filters.
This is a branch of the renowned company General Motors Company. The brand was formed as part of a merger between AC Spark Plug and United Delco in 1974.
Best Motorcycle Spark Plug FAQ:
Q: What is the heat range of a spark plug?
A: The heat range of a motorbike spark plug refers the speed at which it can transfer heat, starting from the firing tip, and into the cooling system. The majority of spark plug creators suggest that the heat range should be between 500-850 degrees Celsius. Each manufacturer will display its heat range in a number. But bear in mind that different brands have different methods of assigning heat ranges. These can be broadly divided into what are commonly known as ‘hot plugs’ and ‘cold plugs’. The former have long insulator nose lengths, which slow down the rate at which heat is transferred from the firing tip to the cooling system. They are best for applications which run at low rpms, and they have the advantages of allowing the plug to self-clean and prevent fouling. Alternatively, you have the cold plugs, which are better for high rpm engines as they have a short insulator nose head, which transfers heat more rapidly from the firing tip to the cylinder head water jacket. If you are not certain, it is always worth asking questions of the manufacturer.
For high performance engines, choosing the right heat range is essential. If you choose one with a heat range which is too cold, the spark plug will not be able to self-clean in the same way, and it will not be able to burn off carbon deposits. On the flip side, if you choose a range which is too hot, this could lead to negative effects such as detonation, pre-ignition, and power loss. Look for a special performance spark plug.
Q: What is the purpose of metal in a spark plug?
A: Different manufacturers use different metals in the center and side electrodes of a spark plug. The metal is meant to channel the high voltage from the spark plug wire through the rest of the plug. This enables it to spark across the small gap between the central electrode and the side electrode, which starts off the combustion process. Hard metals like platinum and iridium are used to reduce the wear caused by high voltage sparks. Also, they help to decrease the rate of misfire, offering a more reliable engine performance.
Q: What is gapping?
A: Your spark plug needs to be properly gapped for the engine to perform properly. When you are shopping for spark plugs, you need to know about the gap specifications of your vehicle, so you can choose one with the correct specifications. Alternatively, you can try and take on the task of gapping the plug yourself. There are plenty of guides online which explain the process in more detail, but you need to start by getting the right tools. Next, you should clean the spark plug and measure the gap carefully. You then use your tool to carefully adjust the bottom electrode, continuing to remeasure the gap until you get it to the correct size.
Q: How often should I change my bike's spark plug?
A: The general answer to this question is: it depends. Some of the factors which can impact how often you change the spark plug are how often you ride your bike, the distance you cover, the quality of the plug you have chosen, and the age of your motorcycle. As a general rule of thumb, new spark plugs should last around 6,000-7,000km. However, it is worth inspecting your spark plugs on a regular basis, as well as checking that all-important gap. You can also perform some basic maintenance including cleaning off any carbon deposits.
Another way that you can tell whether or not a spark plug is still in good working order is the color. If it is light tan or gray, this is a way of telling that everything is A-OK. If you notice that it is a heavy black color with deposits, it could be too cold for the engine. Alternatively, it could mean that there is too much of a spark gap. On the other hand, if you see a bright white color, it may be that the plug has overheated from improper tightening.
Our Top Pick
Of all the motorcycle spark plugs we have discussed in this blog post; our number one pick is this one which comes already pre-gapped. It features an iridium electrode, which is 25% smaller than a platinum one. Some of the advantages of this material include a reduction in voltage requirement and an extended ignition system life. This is a well-known brand in this field, and for us, it is a hard one to beat.