When it comes to looking after your motorcycle, one of the more neglected parts of any vehicle is often the spark plugs. The truth is that motorcycle spark plugs are just as important as the battery, brake pads and clutch in ensuring your motorcycle is running perfectly. Spark plugs aid in the combustion process in engines, and if they aren't functioning efficiently, your motorcycle could develop starting problems. Therefore, here is our guide on proper care and maintenance for your motorcycle spark plugs to ensure a safe and smooth ride every time.

How to Check Motorcycle Spark Plugs

While motorcycle spark plugs can take a lot of heat and pressure during a ride, even the best motorcycle spark plugs need maintenance after a while. Fortunately, this isn't a complex job, and you can easily check them yourself once you know where to look. Here is our guide on how to check motorcycle spark plugs.

1. Find the Spark Plugs

If you want to check the spark plugs on your motorcycle, the first step is to locate where they are installed. While most motorcycles house spark plugs above or beside the engine, every model is different. Therefore, consult your owner's manual if you are unsure where the spark plugs are positioned in your bike. Once you have found where they are housed, make a reference for future maintenance.

2. Remove the Plugs

To properly check the spark plugs for damage, you will need to remove them from their housing unit on the motorcycle. First, gently detach the spark plug wire, being careful not to pull or tug it too hard. Then, use a wrench or socket to unscrew the spark plug from its casing. In most cases, you will need to turn the spark plug counterclockwise to release it. Once detached, place each spark plug on a clean surface, ready for inspection.

3. Inspect the Plugs

Check the spark plug for any wear or damage. A healthy spark plug should have a light brown or grey-coloured tip. The ceramic insulator and electrode should also be intact and unbroken. If the plug is undamaged and in good condition, consider giving it a quick clean with a wire brush and specialised cleaner before reconnecting it. If the spark plug is damaged or worn out, replace it with a similar model, according to the owner's manual.

4. Reinstall the Plugs

Depending on whether you need new spark plugs or not, carefully reinstall the new or existing plugs in their secure location. Carefully screw the plugs back in by turning them clockwise while being careful not to over-tighten them. Securely attach the spark plug wire, and close the casing where the spark plugs are located. Test your motorcycle out to ensure everything is running smoothly.

When to Change Motorcycle Spark Plugs

As a general rule, you should check and change your motorcycle spark plugs every 8,000 to 10,000 miles unless otherwise advised by your owner's manual. However, symptoms of bad spark plugs in a motorcycle can develop at any time. Here are some things to look out for that will indicate when to change motorcycle spark plugs.

Engine Won't Start

Perhaps one of the best indications of trouble with your spark plugs is when the engine refuses to start or takes too long to start. A damaged or worn-out spark plug will make it more difficult to achieve ignition, leading to difficulty starting the engine or unstable idling. If this happens, immediately turn off the engine and check your spark plugs for any issues.

Poor Fuel Efficiency

If you notice that your motorcycle is consuming fuel at a greater rate, it may be an indication that your spark plugs are wearing out. Faulty spark plugs are less effective at igniting the engine, which forces it to consume more fuel than usual. Therefore, keep an eye on your fuel gauge and check your spark plugs if excess fuel consumption remains an issue.

Lack of Power

Damaged or worn-out spark plugs can cause the engine to lose power, making it harder to accelerate or maintain a regular speed. If you've noticed that the engine has been struggling to accelerate or that speed is sluggish and inconsistent, it may be because the spark plugs are failing to ignite the fuel and air mixture effectively.

Misfiring Engine

If you hear the engine stutter or misfire, that could be an indication that the spark plugs are failing to ignite the engine properly. This could lead to damage to other engine components if not dealt with immediately. Therefore, always check the spark plugs the first time you notice any strange engine noises or stuttering.

Discoloured Spark Plugs

As a general rule, healthy spark plugs should have a light brown or grey-coloured tip. Discolourations on the tips are a good indicator that the spark plug needs to be replaced. Check to see whether the plug is damaged—if the plug has a buildup of carbon or ash, as well as any oil or wetness, these are good indicators that the plug needs to be replaced.

Where Are Spark Plugs Located on a Motorcycle?

In most cases, the spark plugs on motorcycles will be positioned near the engine, either above the cylinders or beside them, with a cover in place over them. There are several ways to locate spark plugs on a motorcycle. Look for thick wires leading away from the ignition system to the engine, as these are connected to the plugs. Keep in mind that you may need a socket wrench to remove the cover and that there may be more than one spark plug, depending on how many cylinders your engine has. If you have any difficulties finding the plugs, consult your owner's manual.

How Many Spark Plugs Does a Motorcycle Have?

The amount of spark plugs your motorcycle has depends on the type of engine it contains. Generally, the more powerful the engine, the more spark plugs it is likely to house. Here are some ways to determine how many spark plugs a motorcycle has.

Single-cylinder engines:

If your engine only has one cylinder, then it generally only needs one spark plug. This can often be found somewhere near the engine itself.

Multi-cylinder engines:

If the engine has more than one cylinder, then it will often have additional spark plugs for each extra cylinder. For example, a four-cylinder engine will have four spark plugs.

High-performance engines:

Motorcycles with more powerful engines often need additional high-performance motorcycle spark plugs to aid in efficiency. In most cases, these engines will have two spark plugs per cylinder.

Will a Motorcycle Start With Bad Spark Plugs?

Even if your motorcycle has bad spark plugs it may still start, but less reliably and efficiently as before. Motorcycle spark plugs create a spark that ignites the air-fuel mixture within the engine's combustion chamber, allowing it to start. If the spark plugs are damaged or worn out, they become less effective at creating the sparks needed for combustion until, eventually, they stop working altogether. Therefore, it is important that you check the spark plugs in a motorcycle if you find that your engine is failing to start or is running inefficiently.

How to Choose Your Motorcycle Spark Plugs

When it comes to installing or replacing your motorcycle spark plugs, there are many different types to choose from. To ensure your engine remains in peak condition and can achieve the best performance, it is important to know which spark plugs are best for your motorcycle. Here is our guide on choosing the right motorcycle spark plugs for your vehicle.

1. Consult the Manual

Before you make any decisions about the type of spark plug you want to choose, always consult the owner's manual first. Your manual will be able to tell you what spark plug to use, as well as other details, like size and heat range. If you do not have your owner's manual on hand, consult an expert, such as your local mechanic, for advice.

2. Know the Types

Motorcycle spark plugs differ based on the material the electrodes are made from. Each type of spark plug offers its own benefits and drawbacks in terms of budget, durability and performance:

Copper spark plugs

This is the standard form of spark plug used in motorcycles and offers high-level performance and excellent heat transfer at little cost. The downside is that they wear out faster than other types of spark plugs.

Iridium spark plugs

This type of spark plug offers the best performance as well as the longest lifespan of any material. However, it is also the most costly of spark plugs, so you should always calculate whether this spark plug's long shelf life is cost-effective against the high initial cost.

Platinum spark plugs

This material offers a good compromise between the performance and durability of iridium and the low cost of copper. You can also find double platinum plugs with better durability at a higher overall cost.

3. Check Compatibility

Some spark plugs will only work with a specific make and model when it comes to motorcycles. Using the wrong spark plugs can lead to ineffective combustion and could even cause damage to your engine. To avoid causing any damage to your motorcycle or spark plugs, consult your owner's manual to ensure the spark plugs you choose will work with your specific motorcycle.

4. Determine Heat Range

The heat range of a spark plug refers to its ability to dissipate heat at high temperatures. A cold spark plug works best for high-performance engines and warmer temperatures, while warmer ones are better for colder conditions and engines with a lower RPM. Cold spark plugs are also a good idea if you want to prevent your engine from overheating. Remember that the higher the number, the faster the heat dissipates.

5. Examine the Gap Size

The gap size of a spark plug refers to the distance between the ground electrode and the central electrode. They need to be a certain distance apart, depending on the make and model of your motorcycle. Check the owner's manual to ensure the gap size of your spark plug is suitable for your engine.

Are Motorcycle Spark Plugs the Same as Car Spark Plugs?

Motorcycle spark plugs and car spark plugs both serve the same function: to ignite the air-fuel mixture in the engine that drives its combustion. However, that's where the similarities end, as motorcycle spark plugs are built for a different type of engine compared to cars. Motorcycle spark plugs are generally smaller compared to their counterparts in cars, and they often operate at higher RPMs. They are also often designed to operate in higher temperatures and will deliver a higher level of performance compared with cars.

Best Motorcycle Spark Plugs in 2026

If you are looking for the best motorcycle spark plugs to use in 2026, try the range available from NGK. NGK has been manufacturing high-quality and high-performance motorcycle spark plugs for over 60 years. NGK spark plugs for motorcycles come in both standard and iridium varieties. They are both fuel-efficient and long-lasting and offer a more environmentally friendly option compared to other varieties of spark plugs.

Closing Tips

Checking and maintaining your spark plugs regularly is important when it comes to maintaining the health and reliability of your motorcycle engine. If you run into problems with the engine starting, or you find that it is running inefficiently, check your spark plugs immediately to see if they need replacing. Keep these tips in mind when maintaining your next motorcycle spark plugs:

• Make sure you know where the spark plugs are located on your motorcycle so that you can easily check and replace them when necessary.

• Always check your spark plugs if you have difficulty starting your engine, the motorcycle's acceleration lacks power, or the motorcycle is using more fuel than normal.

• If your spark plugs are miscoloured, broken, dirty or oily, you will need to replace them as soon as possible.

• Always consult the owner's manual to find out what types of spark plugs work best with your make and model of motorcycle.