Parts and equipment for motorcycles, quads, scooters and bicycles

Spark plug

Spark plug

Essential for the proper functioning of your two-wheeler or quad, the spark plug is a piece whose importance is often underestimated par vehicle owners. This key element of the ignition system has a crucial role in starting and overall engine performance. Understanding how it works, knowing when and how to replace it and choosing it wisely is imperative for any two-wheeler and quad enthusiast.

Understanding the Spark Plug

For any vehicle owner, understanding the spark plug is essential for the maintenance and optimization of their two-wheeler or quad.

Definition and role

It is the part of the vehicle responsible for triggering combustion in the engine. It generates a spark which causes the air-fuel mixture inside the cylinder to explode, causing the pistons to move and, par therefore, of the vehicle's engine. It is thanks to the spark plug that your engine starts and runs properly.


The spark plug operates by receiving high voltage from the ignition coil. This voltage generates a spark between the center electrode and the ground electrode of the spark plug. The spark thus produced ignites the air/fuel mixture in the combustion chamber. It is this process that generates the force necessary to start the engine.

The different types of this essential part

There are several types of spark plugs, each with its own unique characteristics and suitable for distinct types of engines and driving situations.

Cold candle

The cold plug is designed to quickly dissipate heat to the engine block. It is therefore preferred for engines subject to high revs or for sporty driving. It has a shorter insulating spout

warm candle

Conversely, the hot plug keeps more heat in the combustion chamber, which promotes fuel combustion. It is ideal for short urban journeys or cold starts. It has a longer insulating spout.


La iridium spark plug, with its iridium electrode, offers better performance and a longer lifespan than the traditional candle. Its stronger spark promotes more efficient combustion of the air/fuel mixture, improving engine performance and fuel consumption.

In so-called standard copper

The copper candle is the most common and least expensive. It offers good conductivity, but its lifespan is shorter than that of other types of candles. It offers the best conductivity but wears out more quickly.


NGK is a benchmark brand for spark plugs, recognized for the reliability and performance of its products. It offers a wide range to satisfy all needs and all types of engines.

Understanding the coding of candles

The coding of spark plugs is not always easy to understand. This combination of letters and numbers indicates valuable information about the spark plug, such as thread type, key size, thermal range, electrode type, etc. It is therefore important to know how to read this coding to choose the best spark plug for your vehicle.

In order to find your way among all the different candle references, we have established a equivalence of different candles with other brands

Discover our guide about coding of candles NGK

The importance for the engine

The spark plug is a key part of the proper functioning of the engine. A spark plug in good condition guarantees a quality spark for optimal combustion. This translates to par better engine performance, fuel economy, reduced pollutant emissions and extended engine life. Conversely, a defective spark plug can cause misfires, loss of power, increased fuel consumption or engine damage.

How to choose the right one for your two-wheeler or quad

Selection criteria

To choose the right spark plug for your two-wheeler or quad, several criteria must be taken into account: the thermal range - which must be adapted to your type of driving, the type of electrode - depending on your performance and longevity, and of course compatibility with your vehicle mode. Also be sure to check the spark plug code.

To avoid making a mistake, simply remove the one in place on your vehicle and take the references noted on it.

Choosing a spark plug requires understanding the reference of the spark plugs in order to determine the models compatible with your machine.

For all brands of spark plugs (NGK, Denso, E3...), the reference is represented par a series of letters and numbers (example: BR9ES). This codification is broken down into 5 parts: a first series of letters (B in our example) followed by a letter (R), a number (9), a letter (E) and finally again one or more letters (S).

Each of these elements corresponds to exact characteristics of the spark plug: diameter of the thread / type of resistance / thermal resistance / length of the thread / type of spark plug.

The most reliable brands

NGK, Denso, naraku... There are many brands of spark plugs known for their reliability, performance and durability.

When and how to replace?

Misfires, difficulty starting, unstable idling, loss of power, reduced engine performance, increased fuel consumption... These symptoms may indicate a faulty spark plug. Changing faulty spark plugs quickly is essential to avoid damaging your engine.

The replacement process

How often you need to replace spark plugs depends on several factors, including the type of spark plug, the type of vehicle and your driving style.

Certain signs like difficult starting, loss of power or excessive fuel consumption may indicate that it is time to change them.

To know when to replace your spark plugs, it is best to refer to your vehicle's service manual.

Replacing spark plugs is a fairly simple operation that most two-wheeler or quad owners can do themselves. Follow our advice by consulting our tutorial: how to replace your spark plug

Maintenance of these elements

Regular maintenance of your spark plugs is essential to maintaining optimal performance of your engine. This includes regular cleaning of the spark plugs to remove deposits and checking the electrode gap.

Comparison of the advantages and disadvantages of different spark plugs

Each type of spark plug has its own advantages and disadvantages: copper spark plugs are affordable but have a short lifespan, iridium spark plugs offer excellent performance but are more expensive, cold spark plugs are ideal for sporty driving but can be subject to clogging at low speed... It is therefore important to weigh these different factors before making your choice.

In conclusion, choosing the right spark plug and ensuring regular maintenance are crucial steps for the proper functioning and longevity of your engine. At 50 Factory, we offer you a wide range of quality spark plugs, suitable for all types of vehicles and all budgets.

Remember to check the other categories of ignition parts to find all your items: suppressor and spark plug wire, ignition coil, CDI case, ignition cover, stator and ignition rotor, turbines.