Dirt bike spark plugs are essential to a motorcycle’s performance, and depending on whether you ride a two-stroke or four-stroke, how much attention you should pay to them will vary.
When you go off-roading, a spark plug ignites your fire, burning it bright. The spark plug on 2-stroke and 4-stroke dirt bikes is required, but since most owners tend to pop it in and forget it, it often gets fouled, sooty, or burnt up.
In most cases, this occurs at the gate drop or on trails far from camp. It’s easy to transport a dirt bike spark plus, and whether you ride the track or trails, you should always carry a spare or two.
So, here we’ll cover the ins and outs of dirt bike spark plugs in this ultimate guide!
What is a spark plug?
Essentially, a spark plug ignites the fire that starts your dirt bike engine, delivering a continuous spark that fires once per full revolution on a two-stroke, and once every other full revolution on a four-stroke.
It can be difficult to understand spark plugs and their technical aspects, and the more you dig into them, the more questions you’ll have. This guide will, however, keep things simple.
Dirt Bike Spark Plug & When to Change?!
In dirt bike engines, spark plugs ignite the fire, producing a continuous spark once per full rotation on a two-stroke machine and once every other cycle on a four-stroke engine.
It can be challenging to dig deep into spark plugs and their technical aspects, and the more you explore, the more questions you’ll have. But as we keep things simple, you’ll go through an easy process.
Changing the spark plug on a 2-stroke
A 2-stroke dirt bike’s spark plug can foul out faster due to oil mixed in with the gasoline than a 4-stroke’s. Of course, this also depends on carb tuning.
It is common for riders to tune their carburetor on the rich side, which may adversely affect their spark plug. That’s why you must always have at least one spare spark plug in your toolbox. Remember to inspect it before riding routinely! Also, elevation plays a significant role when it comes to spark plugs on 2-strokes as well because of tuning issues.
Unfortunately, you can’t flip a switch and adjust for different elevations like with non-fuel injected 2-strokes; therefore, many riders stick with what worked last time or best overall. But remember that if you ride at different heights without adjusting the carb accordingly first, the spark plug will foul much faster!
On a positive note, though—fuel-injected 2-strokes do self-calibrate for height. That helps prevent plug fouling, so they’re worth considering too!
But if you’re riding a non-fuel-injected bike, be prepared for extra maintenance!
Changing the spark plug on a 4-stroke
If you’re a 4-stroke dirt bike enthusiast, you know that maintaining maintenance is crucial to get the most out of your ride. The owner’s manual will provide the recommended service interval or how often you should change it.
However, if you need help finding your manual or prefer to avoid looking for it, replacing your 4-stroke dirt bike spark plug at least once a year is an excellent rule of thumb. It ensures optimal performance and fuel efficiency and also minimizes the risk of engine issues down the road.
Additionally, when planning an engine rebuild – regularly keeping up with routine maintenance like replacing your 4-stroke dirt bike spark plug, you’ll help extend its lifespan—also improving its overall functionality on and off-road.
How To Change A Dirt Bike Spark Plug?
Step 1:
The first thing you need to do is remove the spark plug. With a socket wrench or spark plug wrench, remove the spark plug cap and loosen the spark plug itself.
Step 2:
The new spark plug can be inserted once you’ve removed the old one.
Step 3:
Be careful not to overtighten the spark plus as this will strip the thread in the cylinder head, resulting in a costly and difficult repair. You should also be aware of snapping the spark plug inside the cylinder, which can also occur if you overtighten it.
Step 4:
The spark plug cap should be reinstalled after the spark plug is tightened appropriately.
Dirt Bike Spark Plug Gap
So many dirt bikes are available, and so is the spark plug. Whether it’s Apollo 125 spark plug gap or SSR 125 spark plug gap, all have the same role.
The spark plug gap ensures your bike runs smoothly and efficiently. It’s the space between your spark plug’s center and side electrodes. If this gap is too big or small, there can be serious consequences for your engine, such as missed firing or higher temperatures than necessary.
On the other hand, if you get it right – with optimal fuel burn per stroke—everything will run like clockwork. So how do you determine the proper gap?
Grab a spark plug gap tool and consult your owner’s manual. Based on your bike’s make, model, and year, the manual will tell you what size of 0.5 mm, 0.6 mm, or 0.7 mm (etc.) to use. Using the tool allows you to adjust accordingly depending on its current state.
What are the Key Measurements of a Spark Plug?
Diameter
Having the wrong spark plug diameter could result in the plug not fitting into the combustion chamber, the plug being damaged, or the internal parts of the bike being damaged.
Reach
This is determined by the plug’s reach into the cylinder. There must be a correct distance between them. Insufficient length will result in non-effectiveness; too much length will result in pre-ignition, jamming, or even damage the valve.
Heat range
According to the distance from the tip of the insulator to the ceiling ring, the plug’s heat range is stamped on its side. Shorter distances indicate colder plugs; longer distances indicate hotter plugs. Too hot spark plugs can cause pre-ignition. In contrast, a cold plug can wear out more rapidly.
Spark plug gap
Gaps between center electrodes and grounded electrodes are what define spark plugs. A larger gap produces a bigger spark. The spark, however, is more likely to occur at a greater distance due to the higher voltage required. As a result of a shorter distance, a smaller spark will occur, and the air-fuel mixture may not burn completely. For each motorcycle manufacturer, the gap distance between the spark plugs will be specified.
Dirt Bike Spark Plug Number: What Does It Mean?
When choosing a spark plug for your dirt bike, the “spark plug number” is essential. It’s not just about grabbing any old spark plug off the shelf and hoping for the best. Consult the owner’s manual of your dirt bike to ensure that the spark plugs you pick are compatible with the MMY.
Once you’ve done that, pay attention to the numerical number in the type or model of spark plug you’re considering. The number can range from “5” to “10.” The higher this number, the cooler your plug will be. If you’re running a lower-numbered spark plug in springtime, swap it out for a higher one during summer.
Your engine may suffer serious damage if you do not take action. Your owner’s manual will suggest which spark plugs work best based on the time of year and geographical location. Other letters or numbers in your chosen model will refer to things like electrode type and thread size—factors that can impact fuel burn efficiency, amongst other benefits!
How To Remove a Spark Plug?
Suppose you’re wondering how to remove a spark plug from your dirt bike. Start by pulling off the cap of the spark plug wire to expose the spark plug. You’ll find it sitting inside the cylinder head. You can easily remove it from the outside with a socket wrench that fits snugly over its electrode and fitting.
A spark plug wrench works best because it provides enough depth to fit over these parts and loosen them up for removal. If you have a 2-stroke dirt bike, removing the spark plug should take less than a minute. But if you own a 4-stroke model, you may need to remove your gas tank before accessing the spark plug.
Once removed, replace with new one, carefully aligning threads before tightening in place using either torque or feel (though be careful not to overtighten). It’s important not to strip threads inside your cylinder head as this will require replacing it entirely. Also, beware of overtightening, which can break off plugs rendering them difficult to retrieve!
Note: A torque wrench can help seat everything properly, but most people go by feel instead of risking damage or overtightening issues.
How to Check the Performance of Your Spark Plug?
You can determine how your engine is performing by looking at the spark plugs. This can be done as part of routine maintenance on your car, boat, lawnmower, ATV, or lawnmower.
Getting Started
Firstly, you need to remove the spark plug you want to examine. The following instructions will guide you through the process of removing a spark plug. Begin by looking for signs of damage on the spark plug. The spark plug that was in the cylinder should be examined from the end. The following conditions are likely to occur.
Normal spark plug
On a normal spark plug, the side electrode will have deposits that are brown or grayish-tan in color. Your spark plug is just fine; you can reinstall it.
Carbon fouled
An electrode with black, dry soot and an insulator tip that is carbon-foulled indicates that the plug has been fouled with carbon. You may experience this problem if you have a dirty air filter, drive at low speeds excessively, mix too much fuel with air in your vehicle, or idle the vehicle for too long. If your spark plug is damaged, your mechanic can suggest a replacement, but you may want to consider switching to a “hotter” spark plug (the higher the number, the hotter the plug).
Oil deposits
An oil-foulled plug is identified by black deposits on the electrodes and insulator tip. The oil could be getting into the cylinders through worn pistons or worn valve guides. Seek the advice of a mechanic if you are having trouble finding the leak’s source. After addressing the problem, you can replace the spark plug.
Wet
Wet spark plugs can be caused by flooding in the engine. An engine flood occurs when it does not fire up after several attempts. Spark plugs can either be cleaned or allowed to dry.
Burned
White deposits on the electrodes, blisters on the tip of the insulator, or melted electrodes indicate a burnt spark plug. The engine may overheat, spark plugs may have an incorrect heat range, they may be loose, the ignition timing may be incorrect, or the fuel/air mixture may be too lean. Changing the spark plug is a good idea.
Worn electrodes
An electrode that is worn and eroded is a sign that the spark plug has reached the end of its life. There is a problem with the plug in the engine, and it needs to be replaced.
Broken electrodes
There is a good chance that the spark plugs are installed incorrectly if the electrodes are broken or flattened. In addition to causing extensive damage to your engine, a long spark plug can also cause poor gas mileage and spark plug fouling. Ensure that you have the correct spark plug for your vehicle by checking your owner’s manual.
How To Tell If Your Spark Plug Is Broken/Not Functioning?
Testers for spark plugs can be purchased online for a few pounds. The high tension lead needs to be removed from the plug. The tester’s boot should be attached to the spark plug and the rigid end should be attached to the bike’s high tension lead boot. If the spark plug boot receives current, the tester bulb will flash.
A screwdriver can also be inserted into the spark plug hole and held close to the engine metal section, then the engine can be started. There should be a spark between the screwdriver and the bike if this is the case.
These tests show that current is reaching the spark plug boot, but not whether it is flowing. There is a possibility that the plug isn’t firing inside the combustion chamber – perhaps because it is dirty or wet.
Check your spark plug is working properly
Keep the other end of the spark plug connected to the bike while removing the spark plug from the chamber. Spark plugs should be laid against an exposed metal part of a bike, such as a motor head. You can check if the engine is working by turning it over and seeing if there is a spark. It is preferable to have strong, blue sparks rather than intermittent or orange ones.
Battery issues
Sometimes a plug won’t work because the battery doesn’t produce enough current. You should make sure that your battery outputs at least 12.6V. It is possible to test this with an inexpensive altimeter online. The long-term benefits of such an investment are obvious.
Spark plugs require a good connection between the battery and spark plug connectors to function properly.
What are the Ways to Clean a Motorcycle Spark Plug?
Several methods can be used to clean a spark plug.
A wire brush and a carburettor cleaner
With a wire brush, motorcycle owners usually remove dirt and debris from their spark plug heads after applying carburettor cleaner.
Sand blaster
Other users purchase a sandblaster unit to clean the connectors. However, the black media used in such machines may sometimes remain in the spark plug and may well enter the engine. Sandblasting may also result in the ceramic insulator glazing over.
Blow torch
A blow torch is sometimes used by mechanics to burn away debris from electrodes. Reinstalling the spark plug after cleaning may require re-gapping, no matter what method is used.
Final Thought: Dirt Bike Spark Plug
The dirt bike spark plug is a crucial component that plays a vital role in getting your engine up and running. It ignites the fire that starts the combustion process, providing continuous sparks.
The spark plug is crucial in keeping your machine running smoothly. A dirty or worn-out spark plug can result in reduced engine performance, poor fuel economy, and even damage to other parts of the bike. That’s why it’s essential to regularly inspect and replace your dirt bike spark plug as needed.
Using basic tools, this task can be done at home fairly easily. Otherwise, ask for help from your trustable motorcycle mechanic. Being on top of this little detail is the key to a small but powerful component. Each detail counts regarding getting the most out of your ride!
FAQs
What size is a dirt bike spark plug?
Threads. Currently, three spark plug thread diameters and pitch sizes are used on motorcycles and ATVs: 10 mm x 1.0, 12 mm x 1.25, and 14 mm x 1.25. Currently, two thread reaches (lengths) are used: 1/2 inch and 3/4 inch.
Which spark plug type is most commonly used in dirt bikes?
Spark plugs with copper tips are the most popular and standard kind.
How fast can you get with the strongest spark plug?
Platinum spark plugs are more cost-effective than iridium spark plugs while still providing superior performance and fuel economy compared to copper plugs. Platinum spark plugs, like iridium plugs, can withstand cooler temperatures than their copper counterparts.
Which spark plugs are ideal for my dirt bike?
Since copper is an excellent electrical conductor and runs somewhat cooler, it is the ideal spark plug. The expensive expense of an iridium spark plug is offset by its superior performance compared to platinum.
Which brand of spark plugs is recommended?
Because copper is a superior electrical conductor and operates at a slightly lower temperature, copper spark plugs provide the finest performance. Iridium spark plugs work better than platinum ones but are very expensive.