Chinese ATV Trouble Shooting
How to Test for No Spark at the spark plug.
When troubleshooting a no start issue, always check for spark at the spark plug before continuous cranking on the electric starter. You will overheat your starter and compound the problems and burn up a normally good starter.
The easiest test is to have an extra new spark plug on hand. New plugs are cheap and also used for quick testing. Remove your spark plug plastic cap and leave the old spark plug in the engine. Insert the new testing spark plug in the cap and lay it on the cylinder head. The metal part of the spark plug MUST touch metal on the engine for a good ground. Crank the engine and watch for blue spark at the plug. If you have spark then this trouble shooter is not for you. We are going to address the next steps to take IF you have NO SPARK.
Many new Chinese ATV, Dirt Bike and Go Kart Models have numerous safety switches and wires. This quickly confuses many week-end mechanics when the kids are ready to ride. Our trouble shooting technique is fast and does not require any special tools.
There is only 3 electrical components needed to tell this engine when to fire that plug. First is the CDI (short for capacitor discharge ignition). This is a small black box with 5 wires going to it and usually hangs on the frame in a rubber hanger. Most popular is the 5 pin or 5 prong CDI and that 5 pin CDI is what this trouble shooter article is about. Find your CDI on the frame. We will be testing on that box.
Number 2 is the ignition coil and that is easily found because the large wire and cap going to your spark plug is attached on the other end. Find your coil and make sure the small two wires are connected good and not pulled loose.
The final third component is the stator magnetor or magnetic pickup coil. Your stator is located always in the left side engine cover. This is a dry cover that has no engine oil in it and not very hard to remove. Inside this cover you will find a round flywheel with magnets. When these magnets spin around passing the ignition pickup coil mounted on the stator plate, the pick up senses the magnet and tells the cdi to tell the coil to fire that plug.
Here is how we test this 5 PIN CDI system when arriving in our shop and our spark plug tests show that we have NO SPARK. We locate the CDI and remove it from the frame leaving the rubber hanger on the CDI. We unplug the wire harness and locate the center wire - usually a white wire with black stripe or vice versa. Anyway it is always the center wire that plugs into the center pin on the 5 pin CDI. Find an ice pick or very small screwdrive and insert into the harness plug releasing the real small tab that holds the metal connector in the plastic harness plug. In the old days -- the old timers would cut the center wire, not necessary here. Small tab is easily found with ice pick or tiny screw driver and push metal connector out.
Now you should have a plastic harness wire plug in with center wire hanging free. Plug this now 4 pin plastic connector into your CDI box and retest for spark, crank that engine. If you now have a blue spark the chinese engine will start BUT you will not be able to kill it. Removing this wire as directed eliminates your many safety switches, including the handlebar kill switch. You have a safety switch problem and not an ignition system problem.
Still NO SPARK?? - when you retested? Can only be 3 things. CDI, Ignition Coil or Magneto Stator. Here is where you plug in your NEW SPARE CDI that you keep on hand for testing along with your new cheap spark plug. If we plug in a new CDI and still no spark, then we will plug in a new ignition coil and retest, still no spark, we finally will replace the stator magneto in the left side DRY engine cover. Thats how we do it here in our shop in that order. Fast quick and easy. Eliminates the wrong diagnosis when it could be a faulty safety switch or faulty handlebar switch or faulty key switch. Removing the center wire eliminates all the kill or safety switches in the system. Of course once you are done testing and corrected the faulty part, you need to insert your center wire back into the plastic wire harness plug and reconnect so you will be able to use your kill switches again.
NOTE: This test is for the 5 PIN CDI system only
However, we remember testing a Falcon 150cc with # CDI-19, and the Kazuma 150cc kill wire was also the Black/White striped wire. We found a bad key switch during that repair session. !5 minutes or less repair job.