Equipment needed:
Multimeter
Spark plug wrench
New spark plug (if needed)
1. Safety Precautions: Ensure the scooter is turned off and the ignition key is removed before starting the test.
2. Locate the CDI Box: The CDI box is typically a small, black electronic component located near the engine or behind the front cowl of the scooter. It may have wires connected to it.
3. Remove the Spark Plug: Use a spark plug wrench to remove the spark plug from the cylinder head.
4. Connect the Multimeter: Set your multimeter to the AC voltage (VAC) setting and connect the leads as follows:
- Connect the positive (red) lead of the multimeter to the spark plug wire.
- Connect the negative (black) lead to a ground point on the engine (usually a bolt or metal surface).
5. Check for Power: Turn on the ignition key but do not start the engine. The multimeter should display a voltage reading. A normal voltage reading for a CDI box is typically around 50-100 VAC.
6. Check for a Spark: Hold the removed spark plug near the engine block with the plug wire connected. Ensure the spark plug is grounded properly. Then press the starter button or kick-start the scooter. You should see a spark jumping across the gap between the spark plug electrodes.
7. Check for Intermittency: If the CDI box doesn't provide consistent spark, or the multimeter readings fluctuate significantly, it may indicate a faulty CDI box. To further test for intermittency, disconnect the kill switch wire if present. If the spark returns, it suggests an issue with the kill switch circuit.
8. Replace if Needed: If the multimeter readings are consistently low or you can't observe a consistent spark, it may be necessary to replace the CDI box. Use the correct CDI box specific to your scooter model.
Note: Be mindful that if the scooter has other issues, such as with the ignition coil, spark plug, or electrical connections, it may still not start even if the CDI box is functioning properly.
If you're unsure about any steps or encounter difficulties, it's best to consult with a knowledgeable mechanic or a professional who is familiar with your specific scooter model.
