To serve as a reminder of the inside circuitry, below is the graphic we previously utilized.
Set your multimeter to continuity mode as a result. Take the multimeter’s leads and link them together first.
If your CDI is functioning properly, there shouldn’t be any noises. However, if you hear any beeping noises when performing the test, your CDI is broken.
At this point, all hope is not lost; if you can repair the damaged part, the CDI can still be fixed.
When a cdi has continuity between ground and any of the other terminal points, it typically indicates that the capacitor, scr, or diode has failed.
There is another way to test the CDI box while it is still attached to the motorcycle’s stator. A blue and white wire often connects the stator to the cdi box itself in cdi boxes.
It’s crucial to test the multimeter’s stator end rather than the cdi end when checking for continuity.
This is due to the fact that connecting any test leads to a linked CDI box is notoriously difficult.
Generally speaking, the voltage, continuity, and resistance are identical to those at the stator end.
You might want to test a few other things. Namely:
- Between 77 and 85 ohms should be the resistance for the blue and white colors. While typically you should receive a resistance of 360 to 490 ohms from the white wire to ground.
You can use this to verify the general health status of your CDI box. If your multimeter’s readings for resistance values fall outside of this range. It is worthwhile to have a mechanic examine it.
In This Article...
How does a CDI box function?
In essence, a CDI box regulates the ignition system of a motorcycle by initiating the ignition and combustion process. The spark plug is ignited by a pulse of electricity from the motorcycle battery that travels through the CDI box. Other elements of contemporary ignition systems outside the CDI box include the battery.
How can you tell if your CDI is malfunctioning?
You’re experiencing a spark issue with your CDI-equipped motorcycle. Misfiring, dead cylinders, backfiring, strange tach behavior, and a plethora of other engine-related issues are just a few examples of symptoms. As the bike warms up, the issue can deteriorate further. It might not even be able to maintain low rpm.
With the exception of the CDI unit, you have tested your battery’s charge, your spark plugs, the condition of your coils, and even the triggering mechanism itself. Possibly your black box, then. Yes, especially if your motorcycle is vintage but yet relatively fresh to have CDI. Black box ignitions typically fail all at once, as opposed to the progressive performance decline you’d anticipate from a motorcycle with a points ignition. (To get around CDI systems’ drawbacks, some riders put points-based systems onto their more recent motorcycles. In contrast, many other riders replace factory points-and-condenser ignition systems with more contemporary ones.)
They are difficult to troubleshoot, thus the idea is to take out every variable until only the box is left. The majority are sarcophagus-like locked off. Even though these systems are designed to require no maintenance, a loose trigger sensor can cause havoc with your bike’s tiny computer. Don’t bank on it. Some manufacturers provide specifications for checking your box pin-by-pin. When troubleshooting black boxes, it is advisable to replace a suspect part with a known-good one after ruling out all other alternatives. When purchasing replacements, use caution. A new replacement might not be returnable once installed, and an eBay special might have the same problem as yours.
Why do CDI tests fail?
As it manages the scooter’s engine, the CDI functions similarly to a computer. It gives instructions to the fuel injectors on when and how long to spray. Additionally, it tells the spark plugs how to operate, particularly when they need to fire. Various factors can cause the CDI to fail. Some of them malfunction due to age, some because of a wiring short, and others because of a defective charging mechanism.
Your scooter’s CDI is connected to the ignition. You will therefore experience fewer or no ignition problems if it is in good shape. Its functions include storing electrical charge and boosting the spark plug’s spark power.
Because the visible signs of a defective CDI box might point in several different ways, the CDI is difficult to diagnose. Sometimes a bad CDI doesn’t even produce sparks. Once more, a CDI box that is close to fail can cause misfires, starting problems, harsh running, and even motor stalling.
One must be cautious before assuming that the CDI is the cause of the illness because the symptoms listed can be ambiguous. Similar symptoms would be present when coil packs, spark plugs, or the fuel pump are malfunctioning. Therefore, you must first ensure that everything else is in order before determining whether your CDI has a problem. The lack of a specific method to check the CDI’s condition is the cause.
If you look after all of your scooter’s components, it will serve you well. Knowing how the CDI functions will enable you to take better care of it by keeping an eye out for any signs of deterioration or when repair is required. The CDI has a brief charging phase and an abrupt voltage increase. It also has a limited spark time.
It will stop working for you if you overuse it. The CDI’s immunity to shunt resistance is one of their benefits. However, because to its short spark duration, the CDI box does not provide adequate ignition efficiency.
Each and every scooter enthusiast should be aware that CDI models can be either AC or DC. These two varieties function differently. It is crucial to have a professional inspect your scooter so they can determine which model is ideal for your make.
How can I tell if the ATV stator is defective?
A battery that charges using a different charger but not while the ATV is in operation is one of the warning indicators that your ATV’s stator is damaged. Other warning signs include loose, broken, or filthy connectors.
Use a multimeter to check the ohms being produced to test your stator and determine whether it is damaged or not. The appropriate range is listed in the ATV’s manual or online.
The fact that your battery won’t charge is the biggest sign that your stator is damaged, especially if your ATV charges when it’s on a different charger but not when it’s in use.
This is a strong signal that the battery is not the problem in this case because it can clearly charge. However, if the stator is damaged, the battery won’t be charged, which will be apparent when your battery runs out of power when not attached to the backup charger.
Your stator may have loose, broken, or dirty connectors, which could be the mechanical proof you need to determine whether the stator is defective.
The part itself stops working as it was intended to when these components fail. Depending on your circumstance, you may either need to clean or replace the problematic part, or you will need to replace the complete stator.
Fortunately, stators normally cost less than $100, although the parts can frequently be acquired for less $20. Knowing this will help you save some money if you only need to replace a tiny part of your stator.
In either case, it’s advisable to have a multimeter on hand so that you can check your stator to be sure it’s the broken part of your ATV before moving on. To give you an idea of what you’ll need, here is an example Fluke Multimeter I own (link to Amazon).
On an ATV, what does the CDI box control?
Commonly Located: A CDI box is the conventional name for the capacitor discharged ignition. The position of the CDI box varies greatly. The CDI box will typically be placed differently depending on the make and model. The CDI box is often fastened to the frame with more than twenty wires entering the box from the electrical harness.
The CDI box is typically square or rectangular in shape. Black plastic makes up the majority of factory boxes, however aftermarket models come in a variety of colors (red is pretty common). On one end of the box, there are typically one to three plugins. The electrical harness and CDI box are connected here.
There could occasionally be extra cables coming from the box. Depending on the brand and type of the ATV, the plugins can differ in size and appearance. The number of pins in the plug can be used to describe CDI boxes in some cases. (This is particularly typical of Chinese and young ATVs.) The CDI box displayed below has six pins.
Features: The stator sends a pulse signal to the CDI box. The timing of the spark plug firing in the engine is then determined. The ignition coil receives a pulse from the box at the proper moment, and the spark plug is subsequently ignited. (To learn more about this procedure, read Ignition Coil Anatomy under Anatomy of an ATV. The reverse limiter, timing, spark, rev limiter, and other factory safety kill switches are all controlled by the CDI box. The CDI box can also manage a variety of other things, depending on the brand and type of the ATV. Consult the wiring diagram in the service manual for more details on your specific model.
Maintenance costs: A CDI box is one of the more expensive parts to replace, with prices varying according on make and model. A CDI box replacement typically costs around two hundred dollars. Fortunately, while frequently being held responsible for starting problems, the CDI box is NOT a common wear component. By thoroughly troubleshooting all of the electrical components, the reason of starting problems can only be identified with certainty. Buying a new CDI box without first making sure that all of the other parts are functional is NOT advised. It is never advised to purchase a CDI box used because there is no way to test one.
Could CDI lead to a weak spark?
Despite the spark being initiated by a CDI box, the COIL might still produce a feeble spark. I would advise checking that all of the connections are clean and secure if the spark from the plug is weak and yellowish. Make sure there is a solid ground between the generator, the bike, and the engine, as well as a solid connection between the coil and the common (ground) (some bikes have added gasket between the genny and base for whatever reason).
Ensure that you have either a resistor spark plug or a resistor cap; never both.
If everything seems good, you probably have a coil that has to be replaced.
The stator won’t spark, right?
Additionally, the stator plays the crucial function of supplying the engine’s spark plugs with power. Your motorcycle won’t spark at all without a stator since your battery lacks the capacity to provide the necessary power levels to produce a spark.