How to test CDI Box with Multimeter?

When troubleshooting the Capacitor discharge ignition box. This article will guide you in detail on How to test CDI Box with Multimeter.  CDI, also known as Capacitor discharge ignition. It is a trigger mechanism with coils, capacitors, and other circuitry inside the black box. This system is available n motorcycles, outboard motors, chainsaws, lawnmowers, etc.

How do I know if my CDI box is bad?

If you see any of these issues, then your CDI box is bad

Rough Running

If you are facing rough running, then there is a problem with the CDI BOX. Because If there is a fault in the box, it won’t fire the coils, making your bike run rough.

The problem in Engine Starting

If there is a problem with the engine starting it means there’s something wrong with the CDI BOX. Make sure to check spark plugs because in some cases it can cause a problem.

If your bike is not starting despite all the effort there is a 100% chance that the CDI box is damaged.

Misfire at low RPMs

If you are facing misfiring at low rpm damaged then the CDI box is damaged. So, if you’re having a similar issue, you might want to check the CDI unit with a multimeter.

What does OL mean on a multimeter?

How to test CDI Box with Multimeter?

Here are different method for how to test the CDI box with a multimeter. If one is not working other will work.

     1. Measure Resistance

• Remove the CDI Box which lies under the seat of Motor cycle.
• Find the connector with blue and white wire coming from stator to CDI box.
• Set the multimeter to 2k Ohms.
• Measure the resistance between blue and white wire.
• This resistance should be between 77 and 85 ohms.
• Like wise, measure the resistance between white wire and Ground.
• Also, this resistance should be between 387 and 487.

If the resistance is not in set limit then there is problem with stator. However, if the resistance lies in recommended spec, reconnect the blue and white connectors.

     2.  Measure Voltage

•  Now, Look for yellow, white and black with white-stripe cables coming from your CDI box to front.
• Rotate the multimeter knob to DC volts and set the range to 250V.
• Connect the Black probe of multimeter with ground.
• Connect the red probe at the end of yellow and pink cable one by one.
• While measuring voltage, crank your bike for few seconds.
• The Voltage should be at least 150V DC.
• If the Voltage is in set limit then CDI box is working properly.

      3. Short Circuit Test

• Connect the black lead with the ground terminal
• Also, Connect the red lead one on any other terminals one by one.
• Make sure to test each terminal.
• If the meter doesn’t beep it means CDI is working properly.
• Likewise, if the meter beep. This indicates that CDI is damaged and short.

Advantages of CDI box

CDI box is the major part of the motorbike. To keep it functional CDI box must be in working condition. The advantages are

      1. Fast Charging 

CDI box helps the battery is fast charging. This will not only save the cost but also save time.

     2. Short transient response

Another advantage of the CDI box is fast voltage rise which is between 3 and 10 kV/µs as compared to the inductive system, which is between 300 and 500 V/µs. Also, it has a short spark duration of approximately 50 to 80 µs.

How to test PCM with a Multimeter?

Frequently Asked Questions (FAQs)

Here are some frequently asked questions about how to check if a CDI box is working.

How do you test a CDI box?

To test a CDI box follow these steps

• Rotate the Multimeter knob to Resistance and measure the resistance between
• Also, Rotate the knob to Voltage and measure DC voltage
• Now, Rotate the multimeter to Continuity and check continuity

Can a CDI box be repaired?

Yes! CDI box can be repaired. But I suggest buying a new one. Because there are cheap and repairing can take a lot of time. Also, for a layman, it is a tough job.

Are ATV CDI boxes interchangeable?

No, ATV CDI boxes are not interchangeable. Because every model of the bike has a different box. For replacement find that one which exactly matches your bike. Otherwise, it won’t work.

What are the symptoms of a faulty CDI box?

The symptoms of faulty CDI box are

• Engine Starting Problem
• Dead cylinders
• Misfiring
• Rough running

Will a bad CDI cause a weak spark?

A faulty CDI box often causes weak Spark. Make sure to check it with a multimeter. Another wise replacement is the only option.

As we have discussed previously the new CDI box is not expensive but you should test it thoroughly using Multimeter before replacement. Some time ATV CDI box is working properly and the other components like spark plug are creating the problem.

After reading How to test CDI Box with Multimeter? you will be able to check the ATV CDI box. We have tried to every aspect of the topic and look for more and try to add those in the next update. How was the article? Let us know in the comment section below.