There are a few ways to test a CDI box, but the most common way is to use an ohmmeter. First, disconnect the negative battery cable. Next, remove the CDI box cover and unscrew the four bolts that hold it in place.
Once the cover is removed, you will be able to see the stator coils and capacitors inside. Using an ohmmeter, check for continuity between each of the stator coil leads and ground. There should be no continuity.
If there is continuity, then the stator coils are damaged and need to be replaced. Finally, check for resistance between each of the capacitor leads and ground. The resistance should be very high (in the megohm range).
If it isn’t, then the capacitor is damaged and needs to be replaced.
- Open the hood and locate the CDI box
- It is typically mounted near the battery, on the fender well or firewall
- Unplug the two wiring harnesses from the back of the box
- Remove the four bolts holding the box to its mount using a socket wrench and lift it off
- Set the multimeter to Ohms mode and touch one probe to each of the small terminals on the back of the CDI box, labeled “B+” and “GND
- ” The reading should be close to zero if there is continuity between these two points
- If not, replace the CDI box
- Touch one probe of your multimeter to either side of each larger terminal on back of the box, labeled “coil” with an arrow pointing toward it
- There should be continuity between these two points as well; if not, replace the CDI box
Bypass Cdi for Spark
If you are having trouble with your CDI unit and are looking for a way to bypass it, there are a few options. One is to use a points ignition system. This will give you a more reliable spark, but may be harder to find parts for.
Another option is to use an aftermarket electronic ignition system. This can be easier to install and may offer better performance than the stock CDI unit.
Credit: dmmotoadventures.com
How Do I Know If I Need a New Cdi Box?
If your CDI box is failing, you may notice one or more of the following symptoms:
1. Your motorcycle will run inconsistently. It may run fine for a while, then suddenly start acting up.
Or it may run well at low speeds but not at higher speeds.
2. You may experience misfires and backfires.
3. Your engine may lose power and stall unexpectedly.
4. Your bike may be difficult to start, or it may start but then die soon after starting.
5. You might see an error code on your motorcycle’s dash display.
How Do You Test a Cdi Switch Box?
When testing a CDI switch box, you will need a multimeter. First, disconnect the kill switch wire from the spark plug. Next, set your multimeter to ohms and touch the black lead to the ground terminal on the CDI box.
Then, touch the red lead to each of the other terminals one at a time and check for continuity. The terminal that has continuity is your problem terminal.
Can a Bike Run Without a Cdi?
No, a bike cannot run without a CDI. The CDI is what ignites the spark plugs in the engine, and without it, the bike will not start. Additionally, the CDI controls the timing of the spark plugs, so if it is not working properly, the engine will run poorly or not at all.
Can Cdi Work Without Battery?
Yes, CDI can work without a battery. However, it will not be as effective as when used with a battery. This is because the battery provides power to the coil, which creates the magnetic field that is used to create the spark.
Without a battery, the coil will not have enough power to create a strong enough magnetic field, and the spark will be weaker.