Skip to content

Chinese ATV No Spark – Troubleshooting Guide

One of the biggest issues with owning a Chinese-made ATV is that there are no service manuals and no wiring diagrams in case something goes bad and you need to fix it.

If your Chinese ATV has no spark even though you’ve seemingly checked everything, then this troubleshooting guide is made for you.

No spark conditions are extremely common on all ATVs, not just Chinese-made ones. All you need is a methodical approach while diagnosing it and you’ll be back on the trails in no time.

Chinese ATV No Spark Troubleshooting

To troubleshoot a Chinese ATV with no spark, you will need a multimeter and a test light.

The ignition system on most 90cc, 110cc, and 125cc Chinese ATVs has only 6 components. If anyone of them is bad, then the ATV will crank but have no spark.

These 7 components are the spark plug, ignition coil, CDI, magnetic pickup, stator, ignition switch, and kill switch.

1. Verify The No Spark Condition

Before we begin troubleshooting, you need to be 100% sure that the ATV really does not produce spark.

To do that, make sure that the battery is good and is fully charged. A fully charged battery should have 12.4-12.6 Volts. You can even connect a car battery in place of the small original battery, as long as the original ATV battery is 12 Volts.

Once you know that the battery is good and ready to go, unscrew the spark plug again, ground its base to the engine, and start cranking.

If there really is no spark, it’s time to start troubleshooting.

2. Visual Inspection

Never ever underestimate the power of looking around for anything that’s obvious.

Check all the connectors and make sure that they aren’t loose, unplugged, corroded, or even melted. Check the wires and look for green oxidation and cuts.

Once you’re sure that everything seems fine, continue with the next step.

3. Test/Replace The Spark Plug

A lot of people simply forget that spark plugs can go bad and I don’t blame them. There’s not that much that can go wrong with a spark plug, so it often gets overlooked.

You can test the spark plug with a multimeter by checking for continuity between the electrode and the end of the plug, but I advise you to just buy a new spark plug. These small Chinese ATV spark plugs cost a few dollars max, so it makes sense to just get a new one that’s sure to work.

4. Bypass The CDI Kill Switch

Most 90cc, 110cc, and 125cc Chinese ATVs have 5-pin CDIs.

Most Chinese ATVs also have janky wiring, especially when it comes to the kill switch. To get around that, we are going to bypass the kill switch. In many cases, this will make the ATV have spark and run again. Be warned that you won’t be able to stop the engine with the kill switch if you bypass it, so be ready to disconnect the negative battery cable to kill the engine.

First, locate the CDI. It’s this small black box on the frame.

Disconnect the connector going to it and check if the CDI has only 5 wires going to it. If that’s not the case and your CDI has fewer or more wires, then this troubleshooting guide won’t work for you.

With the connector disconnected find the center wire (most often white wire with a black stripe). Next, using a pick or a small screwdriver, push out the center pin from the connector. You want to leave that center wire loose and out of the connector.

Now plug the connector back into the CDI and try starting/cranking the engine. Beware that you bypassed the kill switch and if the engine starts, the kill switch will not stop the engine.

If the engine runs or if you have a spark, then congratulations!

If not, then continue with troubleshooting. You can leave the center wire unplugged while you’re troubleshooting, but remember to push it back in once you’re done, otherwise, you won’t have a working killswitch.

5. Check The Ignition Coil

Another common reason for no spark is the ignition coil.

First, unplug the spark plug from the coil wire and unplug the two connectors at the other end of the coil.

Turn on your multimeter and set it to continuity mode or the Ω symbol.

Measure the resistance between the two terminals of the ignition coil. You should see less than 1 Ohms and not zero, most likely 0.5-0.3 Ohms. If you measured over 1 Ohm or 0 Ohms, then the primary winding of the ignition coil is bad and the whole ignition coil needs to be replaced.

Now it’s time to test the secondary winding.

Measure the resistance between any one of the connectors and inside the spark plug wire boot (where the spark plug goes). You should see a resistance of around 6k Ohms.

One problem with this test is that the resistance of the secondary winding can be different on different model ATVs and there’s no way of knowing which values are good. But if you see below 1k Ohms and above 8k Ohms then it’s very likely that your ignition coil is bad.

6. Verify The CDI AC Power Feed

The 5-pin Chinese ATV CDIs are powered by alternating current straight from the stator. Let’s check if the stator is supplying enough AC voltage to power the CDI.

With the CDI connector unplugged, test the AC Ignition Power pin at the connector by cranking the engine. Touch one lead to the AC Ignition Power pin at the connector and the ground pin, battery negative, or any bare metal surface.

You should see more than 40 VAC while cranking. If you’re getting less than 40 Volts AC, then the stator is going bad and needs to be replaced.

Related: 6 Most Common Bad Stator Symptoms on an ATV

7. Check The Ground To The CDI

To verify that the CDI is getting good ground, you will have to use a test light. A multimeter is not up to the task as it will not load the circuit.

With the CDI connector disconnected, connect your test light to the battery positive and touch the ground pin on the connector. The test light should light up.

If the test light stays off, then the CDI is not getting a good ground and you need to either fix it or run a new ground wire to replace it.

8. Verify That The CDI is Getting a Timing Signal

This is our last check before we can confidently say that the CDI is bad.

With the CDI connector disconnected, measure the AC voltage going to the Timing Signal pin at the connector. Touch one lead to the Timing Signal pin at the connector and the ground pin or battery negative. Start cranking the engine and watch the AC voltage readings on the multimeter

You should see 0.2 to 0.4 VAC. If not, then there’s a problem with the pickup coil or the reluctor.

9. Small Final Checks

If you’ve checked and verified that everything else up to this point is working properly, then it’s 99.999% likely that’s the CDI has gone bad and needs to be replaced.

But before we can make the call to replace the CDI, you need to make a few final checks if you want to. These little things can get overlooked and really screw you over, but considering that the CDI is pretty cheap, you won’t loose much, even if you decide not to do these final checks.

So we’ve checked all of the components apart from the CDI and verified that they work. But we did not check all of the wiring between these components. We checked most of it, but not all.

This can really bite you in the end, so get your multimeter and check the resistance of each wire between those seven ignition system components. It should take you just a few minutes to do.

Once you’ve done that, consider checking if the magneto under the alternator cover has not jumped the timing. Yes, these Chinese ATV engines have fixed timing, but on very rare occasions the small woodruff key on the crankshaft can be inserted improperly and let the magneto turn out of phase. Again, this is very rare, but can happen.

You will still measure a timing signal, but it would be way out of phase.

10. Make The Call to Replace the CDI

What we’ve done so far is check everything else but the CDI. We did that since the CDI is pretty much impossible to test if you don’t have a service manual with the correct specs to compare against.

Now, if everything else is working as it should, and the CDI is getting good AC power, Timing Signal, Ground, and the kill switch is bypassed, then the CDI is the reason why your Chinese ATV is getting no spark. It’s getting all the inputs it needs to produce spark, but since it does not produce spark, then it means that the CDI has gone bad.

Final Thoughts

Congratulations!

You’ve reached the end of this troubleshooting guide and fixed your Chinese ATV that had no spark.

Luckily, the ignition system components on small 90cc, 110cc and 125cc Chinese ATVs are really simple. All it takes is a good troubleshooting plan and some patience.

Leave a Reply

Your email address will not be published. Required fields are marked *