How to Change Motorcycle Spark Plugs?

Spark plugs are components of motorcycle ignition; power flows from the bottom, jumps to the lower electrode, and produces a spark. The power flow is essential to cause ignition of the fuel-air mixture, which leads to engine stroke. 

How to Change Motorcycle Spark Plugs? You can change motorcycle spark plugs by disconnecting the connected wire manually, adjusting a socket on old spark plugs, and removing it. Adjust the new compatible spark plug, tighten it with a socket, and reconnect the wire.

According to the design and model, the motorcycle ignition has 2 to 6 spark plugs. You can find them on the upper side of the engine, with rubber boots coverage and connects through electric cords. 

What is the method to change motorcycle spark plugs?

Several people change the malfunctioning spark plugs on their motorcycles without expert assistance. You can replace them in about 45 to 65 minutes without professional help. 

In this procedure, their correct selection is essential. You can select them by assessing their compatibility with the ignition system. 

Owner manual indicates their shape, quality, and performance abilities. The selling stores guide beginners about their correct versions. 

You can use a tool kit that includes sockets, wrenches, and screwdrivers. Rubber grommets have additional grip over them, and you can select them from nearby hardware shops.

You can locate them and pull the connected electric cords. Their numbers are 2 to 4 on a standard motorcycle.

Their number increases to six according to the design advancement of motors. You can hold the wire manually and pull it with force. 

Adjusting a socket on it provides excessive grip. Instead, you can adjust the socket wrench on it and rotate it in the opposite position.

Heat can expand the metallic components, which makes the procedure challenging. However, these procedures are easy and fast when the motor is working at a low temperature and does not work.

Now, you can hold it with your fingers and pull and remove it. Assessment of the gap in their new and high-performance options is essential.

It is a necessary factor that determines its performance and lifespan. You can consult the owner’s manual and check all the specifications.

The selection of pre-gapped options is beneficial. It makes the procedure easy and fast. You can add the new spark plug in the mounting area and avoid cross-threading. 

With a socket, you can tighten it and avoid additional force. You can adjust the washer on it and fit it firmly on the motor. 

Again, you can rotate it clockwise with a similar socket. Over-tightening can damage the thread, which moves in the built-in cylinder and reduces engine performance by damaging pistons.

You can reconnect the cord and adjust it with the motor power circuit.

How often do you change motorcycle spark plugs?

They have an average lifespan of about 17000 to 25000 miles in motorcycles. However, the life expectancy varies according to the layout, engine performance, and stability of these components.

They are ignition-producing parts of the motors. Moreover, they undergo more strain, and high temperature affects them.

In such circumstances, their shelf life reduces from the original range. As a result, the engines of adventurous and off-road motorcycles undergo more strain.

On them, they break and malfunction more than standard motorbikes. They need replacement more often because these ignition-causing components cannot fulfill the standard life expectancy. 

It is advisable to inspect and clean them regularly. Without maintenance, thread breaks and seizes, which reduces its lifespan. 

Why would you change motorcycle spark plugs?

You can change them when they undergo failures and malfunctions. Due to the following problems, motorcycle spark plugs require replacement. 


The spark plugs of motorcycles become old with time. In such circumstances, their failures, cracks, and damages become prominent. 

They lose their standard functionality and cannot perform ignition. Moreover, they cannot start the engine because power reduces. 

These old components are dangerous for the engine and require change. For example, you cannot ride motorbikes with old spark plugs because it causes motor failures.

Over time, dust accumulates over them, which leads to misfiring. During misfires, the unburned and unused fuel can damage the engine cylinders and their walls.

Pressure regulated heat

The ignition time of the air-fuel mixture increases in a few motorcycle engines. It produces excessive pressure, which generates high temperatures. 

Excessive torque, deposits of combustion unit, and under-strain riding produce heat. In addition, the high temperature can break the topside of spark plugs.

They fail and cannot perform ignition of fuel and air mixture. It disturbs the overall ignition, and the motor cannot get enough power to start. 

Their cooling system malfunctions and damages the engine cylinders through pre-ignition. In such circumstances, their swap is necessary to stabilize the ignition. 

Variable gap and carbon accumulation

Motorcycles have specific spark plugs which have particular gapping. A few people change their gaps with special tools. 

Sometimes, the gaps become excessively small, which can weaken them. They lack power, cannot complete the air-fuel mixing, and the combustion unit fails. 

However, the gaps with more width are dangerous, lead to improper firing, and result in their malfunctioning at the highest accelerations. Their replacement is essential to reduce misfiring.

Low-speed riding, excessive use, and clogged air filter result in carbon accumulation on their surface. They malfunction, lack power, damage the motor, and need a swap. 

Signs that motorcycle spark plugs are bad

Several symptoms indicate that spark plugs on a motorcycle are bad. However, I have explained a few prominent signs. 

Engine overflooding

Excessive gas accumulation inside the motorcycle engine and its combustion chamber causes overflooding. It happens when the combustion unit cannot burn the internal gas. 

As a result, the performance of spark plugs, connected cords, and other components reduces. The engine cranks while you start your motorcycle.

It indicates wiring faults and an incorrectly working voltage circuit. As a result, the engine does not start because it does not get enough power for a stroke. 

Overflooding of the engine is a significant sign of their failures because they have a direct connection. 

Misfire and backfire

The motorcycle engine undergoes misfiring when the spark plugs fail. In such circumstances, motorcyclists lose momentum at various speeds.

They break and can alter the rhythmic movements. As a result, the engines misfire and show their malfunctioning. 

You can assess the engine misfire when the motorcycle does not work. Also, you cannot start it at standard momentum and acceleration. 

The combustion reduces, which decreases the stroke power. However, the loud, unwanted sounds originate from the exhaust system. 

These sounds indicate their malfunctioning conditions. It leads to backfires because they produce intermittent power flow.

Engine backfiring happens when the unburned gas or fuel moves backward in the relevant cylinders. As a result, they break and cause these backfires, which generate loud noises. 

Particular odor

You can sense a particular smell that originates from the motorcycle exhaust. However, the odor indicates the failure of spark plugs.

The smell produces when they cannot utilize and burn the mixture of fuel and air. The incomplete combustion produces this burning odor, which is more around the emission unit. 

The non-utilized fuel can flow inside the exhaust, and the tailpipe produces this odor. It indicates their insufficient power for work and efficiency. 

Furthermore, they malfunction and cannot start the engine.

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