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How to Fix a Dirt Bike With No Spark: Step-by-Step Guide

Nothing is more disappointing than trying to start your dirt bike, hoping for a ride only for you to realize your dirt bike won’t start. Trying to figure out what the issue is with your bike can be even more frustrating. If you are a rider, it’s only a matter of time before you experience this “no spark” condition.

To fix a dirt bike with no spark, you must remove the spark plug from the cylinder block, put it back in the ignition coil, and kick start the bike to check for the spark. If there is no spark, replace the plug with a new one and double-check all the electric components and repeat the process.

The rest of this article will list a step-by-step guide to fix a dirt bike without a spark and discuss other topics related to this question.

Start With the Rather Obvious Issues

Confirm you have fuel in your tank. Most riders will check the fuel gauge, which may display a full tank. It is, however, worth noting that gauges can malfunction. Listen for a slosh of gas in the tank when you joist your bike before assuming the worst. If you confirm there is fuel in your tank, you can go ahead to check for other components.

While ensuring the kill switch is off looks quite apparent, your bike may fail to start. Most riders rarely use the kill switch; therefore, leave it on after use and forget to switch it off, or someone else might have flipped it on by mistake. Consequently, it is worth checking since the engine is cut off when the kill switch is on, meaning it cannot start. Besides, checking out the kill switch will only take you a minute and could save you lots of time.

Make sure to engage the clutch before you start the bike. This might be common knowledge to an experienced rider; however, a newbie may easily forget about it. It could be the reason why your motorcycle won’t start. It is also possible that your clutch switch is damaged. Pumping the clutch a few times could help you reset the switch; however, you may need a more permanent solution, maybe a clutch replacement.

If your bike has a fuel valve, ensure that it is set to an on position. If it is set in the wrong position, your bike will not start. Please turn it on, and then give it a few minutes for the carburetor float bowls to fill.

Check if the Battery Is Good

After you have ensured that all the basics are set, it’s time to check if the battery is okay. Your battery could be the issue if you have the following signs:

  • Dim running lights
  • You hear a clicking noise every time you turn your key
  • A short-lived crack of the starter

If you are still not sure if your battery is in good condition, then it is time to inspect and test it. A visual inspection of the battery will involve the following steps:

  1. Check for a broken terminal.
  2. Check the battery for leaks.
  3. Look for bumps or cracks on the battery case.

If all is okay, it is time to check for the voltage. You can decide to do it yourself or take your battery to an auto shop. You will use a digital voltmeter to load test the battery. The voltage readings of your battery should read between 9.5 and 10.5 for approximately 30 seconds. If the readings stay stable, your battery is all good, and your bike most probably has another issue. 

Fortunately, it still does not mean you have to call a mechanic or cancel your trip. There are still other things you can troubleshoot to find out why your bike will not start.

Check Your Spark Plugs

The no-spark issue is statistically one of the most common problems for riders. You should note that it does not mean you start disassembling your bike right away. The very first place to start is your spark plugs. 

To test your spark plugs:

  1. Remove plugs from the cylinder head.
  2. Plug them into the plug cap.
  3. Holding the plug up to the head bolt, turn over the engine.
  4. A yellow or blue spark bridging the gap signifies that the spark is strong enough to ignite the cylinder’s fuel/air mixture.
  5. In case there is no spark or the spark is too weak, consider charging your plugs and try again.
  6. If the spark seems strong, but your bike still won’t start, you will need to keep testing. 

You can also visually inspect your plug wires and caps to ensure that they are okay. Usually, your bike will still run even when they are in bad shape; however, you will not have a smooth ride. You must make spark plugs checking a part of your routine maintenance as it will improve your bike’s general condition.

Sometimes, the spark plug might be okay; however, the connections to it might be faulty. Ensure that you inspect both the spark plug and the connections to it, to make sure that everything is good before you check another thing.

Ensure That Your Bike Is Turned On

This may seem obvious, but it should be noted that the ignition switch can fail. Newer bike models have an anti theft feature that prevents the bike from starting when the switch is bypassed by hot wiring. The switch must be turned on for the bike to start. When switched on, the multi-tester will display a positive electric flow from the switch to the coil. If this is not the case, then it is a sign the switch is broken.

Ensure That the Power Leaving the Switch Gets to the Spark Plug Caps

In step 2, you ensured there was power leaving the switch. Now, you will need to ensure that this power is reaching the spark plug caps. For this test, you will need to use a bulb tester or a multimeter. The tester will display an on and off reading for every engine revolution. If there is no record of an alternating flow of current, you may need to replace the spark plug wire or the spark plug cap.

Ensure Your Battery Is Fully Charged

Sometimes with a no spark situation, the problem is not severe; it could be a little as an undercharged battery. Therefore, it is imperative to check every component of your bike without jumping to any premature conclusions. An undercharged battery will not be able to build up enough cranking speed making ignition impossible.

Check your battery to ensure it is fully charged. If it is fully charged and your bike still does not start, you can go on and check elements of the ignition system.

Carry Out a Wiring Inspection

Make use of a wiring diagram to carry out an inspection. The wiring diagram of your dirt bike can be found online. Every wire should have continuity between its terminals. Get a visual of every wire, its connection as well as its path. Also, ensure that it is secured; use your finger to ensure it feels tight. A ground wire should be continuous to the ground, while non-ground wires should not have continuity.

However, the wires should have continuity with themselves at the system. A wire without continuity creates an open circuit, which will cause the ignition system to act as if the pickup coil is faulty, resulting in a no spark condition. A dirt bike is often exposed to harsh conditions that could easily cause an open or a grounded circuit, broken insulation, which leads to a no spark condition. 

Statistically, wiring problems are more common than component problems. It’s thus imperative that you inspect your wiring thoroughly. Motorcycles have fuses that can blow just like in a car. Having a fuse kit with you is essential as you will be able to replace the blown fuse. If your fuses keep blowing after you have replaced them, this could sign a more serious electrical issue in your bike’s wiring. 

Check the Fuel System

Your bike may not start because of fuel issues, especially if stored for a long time. The fuel in your fuel tank could destabilize over time and therefore fail to combust. In this case, all you need is fresh gas in your tank to have your engine come to life. 

When your bike has been stored for a long time, its fuel system is likely to dry out, resulting in cracks and plugging of the fuel filters. These will result in less fuel or none at all, passing through and causing your bike not to start. 

Once you have identified the issue is with a clogged petcock, rattling the petcock could help dislodge a blockage. However, you might need a deep cleaning or a replacement before your bike can start and run again.

Your bike may also fail to start because it is flooded. If this is the case, the solution is to unflood your engine. Follow these steps to unflood your engine:

  1. Remove the spark plugs.
  2. Turn off the choke and turn over the motor until the excess gas has dissipated.
  3. If you are not in a hurry, you can allow your bike some time for the extra fuel to evaporate.

Besides fuel, your dirt bike will need air to start and run. Your motorcycle needs the right amount of air mixing with the fuel. A broken vacuum line can cause too much air to get into the combustion chamber, which will alter the fuel/air mixture, causing the engine to fail to ignite. Ensure you check for holes or a crack on your vacuum lines. Resealing the cracks and holes will solve your problem.

Sometimes, resealing may not be possible, which may force you to have a replacement before you can have your bike running again. It is also possible for your issue to be too little air. Ensure that air can pass through your filter; in case there is an issue here, cleaning your filter could quickly fix up the problem.

Test the Specific Component of the Ignition System

Sometimes troubleshooting the general problems will not be enough. To conduct specific components testing, you will require a few tools, a multimeter that will be used to measure the voltage as well as resistance, and a PVA to enable the multimeter to read the rhythmic voltage, where the voltage fluctuates significantly over a short time.

  1. Spark plugs should be installed in the cylinder; functional plugs should also be installed on the caps.
  2. Ensure that the spark plugs on the caps are grounded to the engine.
  3. Place all the ignition circuit buttons in the run position.
  4. Plug-in the connector to be tested for peak voltage.
  5. Use the electric starter or kick-starter to turn over the engine.
  6. Use the multimeter and Peak Voltage Adapter (PVA) to measure the peak voltage. 
  7. In case the peak voltage is not within the specified range, test other possible locations such as the crank position; test the sensor peak voltage at this position as well as the ECM connector.

Use your service booklet to inspect the ignition coils, including peak voltage testing and resistance testing. In case the peak voltage testing specifications are not provided, measure the primary resistance between the ignition primary coil’s two terminals. If the loop has only a single terminal, measure the primary resistance between the terminal and the ground.

Additionally, test out the secondary resistance between the principal ignition terminal and the spark plug top. If the ignition has two spark plug wires, test the secondary coil resistance between the two plug caps. Check the resistance with the caps removed from the wires; also replace the ignition spark plug, coil, wires, or caps if the resistance is out of range.

Next, you need to check the pickup coil, exciter coil, and crank position sensor for peak voltage and resistance following your service manual. Please check this from multiple locations such as the ECM connector and the coil connector. This way, you will determine if the element is running correctly, as well as if the wiring is in one piece.

You will also be required to inspect the switches in the starting system to ensure continuity and ensure using your service booklet or wiring illustration. Generally, the controls involved include the ignition switch, side stand button, gear position switch, tip-over, and the reverse override, among other safety switches in the ignition system. In case of faulty switches, make sure to replace them and their corresponding wiring.

Determine Whether the ECU or ICM Is Faulty

In most cases, the only way to determine that the ECU or the ICM is faulty is by ruling out all other possibilities; resistance checks for the Ignition Control Module (ICM) or the Engine Control Unit (ECU) are carried out only on rare cases. Unfortunately, most riders want to jump onward and conclude that the ICM or ECU is faulty without inspecting the whole system. 

The truth is that a corrupt wire is a more likely cause for your trouble than a defective component. Therefore, it is essential that you trust the process and first inspect the system without rushing to any conclusions. Do not consider replacing your ICM or ECU lest you are entirely sure it is the faulty one. 

Bear in mind that this is only possible if you have carried out a full diagnostic to ensure that every ignition structure, components, wires, switches, and connectors are perfect. If you jump to conclusions, you may end up spending a lot of money and time unnecessarily.

The following is a video on how to fix a dirt bike with no spark:

Things You Shouldn’t Do When Trying to Start Your Bike

There are quite a number of things you should do to troubleshoot your bike; however, there are some that you should not try.

  • Do not overlook the small things. There are some seemingly simple things to consider when your bike will not start and end up saving you both time and money. Start with the straightforward stuff before you head to the complicated stuff.
  • Do not jump start the battery with a car. You might feel tempted to check if the reason for your bike’s failure to start is the battery, and you might want to jumpstart it like you would your car. Note that jumpstarting your battery might not be the way to go as the spike in voltage could fry your microprocessor and your bike system due to the voltage difference.
  • Do not void your warranty. If you have a warranty for your bike, avoid rendering it void by carrying out repairs. Avoid taking measures that go against your warranty terms; instead, get approval from the dealership or manufacturer first.

Conclusion

Having a dirt bike that won’t start can be frustrating but before you lose your mind over it, take your time to cross off some of the simple pre-trip list things. Sometimes you will manage to get your bike running again without much of a hassle, but sometimes you will need professional help. These steps will help you figure out what could be wrong with your bike and get repairs started.

Levi Bath

I'm the co-creator of OffRoad Lifestyles. I live in Loveland, Colorado with my wife and 3 kids. My wife and I have spent a lot of time out on the sand dunes near Walden, CO and we both love offroading and camping.

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