If you are planning to build a 110cc dirt bike or upgrade its electrical system, it is important to know how to properly wire a CDI (capacitive discharge ignition) unit. The CDI is responsible for providing an electric charge to the spark plug that ignites the fuel in the engine. Without a functional CDI, your dirt bike won’t run at all. Follow this guide to learn more about the 110cc CDI wiring diagram and how to wire the CDI unit to your dirt bike.
What is a CDI?
A CDI is an electronic ignition system that uses capacitors to store and discharge energy to the spark plug. When the engine’s crankshaft rotates, it creates a magnetic field that generates an electric current in the CDI’s coil. This current charges the capacitors, which store the energy until the CDI’s transistor triggers the discharge. This high-voltage discharge generates the spark that ignites the fuel in the engine.
Most 110cc dirt bikes use a 5-pin CDI unit that connects to the engine, ignition coil, kill switch, and other electrical components. The CDI’s pins are usually labeled as follows:
| Pin | Function |
|---|---|
| 1 | Ignition coil |
| 2 | Ground |
| 3 | Kill switch |
| 4 | Engine |
| 5 | Battery |
Wiring the CDI
Before wiring the CDI, make sure that the engine, ignition coil, kill switch, and battery are in good condition and properly connected. You will also need a wiring diagram for your specific make and model of dirt bike, as the colors and locations of the wires may vary.
The basic wiring connections for a 110cc CDI unit are as follows:
Pin 1: Ignition Coil
The ignition coil is responsible for producing the high-voltage current that is sent to the spark plug. Connect the CDI’s pin 1 to the positive terminal of the ignition coil. The negative terminal of the coil should be grounded to the frame of the dirt bike.
Pin 2: Ground
The CDI’s pin 2 should be connected to a suitable ground point on the dirt bike’s frame. Make sure that the ground connection is clean, secure, and free of corrosion.
Pin 3: Kill Switch
The kill switch is a safety device that stops the engine if the rider falls off the bike or loses control. Connect the CDI’s pin 3 to the kill switch wire, which is usually black or yellow. When the kill switch is in the “off” position, it should ground the CDI’s pin 3 and stop the engine.
Pin 4: Engine
The CDI’s pin 4 should be connected to the engine’s pickup coil, which senses the rotation of the crankshaft and generates an AC voltage signal. The pickup coil wire is usually green or blue. Make sure that the pickup coil is properly aligned and has the correct air gap for your engine.
Pin 5: Battery
The CDI’s pin 5 should be connected to the positive terminal of the battery. Make sure that the battery is fully charged and in good condition, and that the wiring connections are tight and free of corrosion.
FAQ
What should I do if my dirt bike won’t start?
If your dirt bike won’t start, there could be several possible reasons. Check the fuel level, spark plug, air filter, and carburetor to make sure they are clean and functional. If those are not the issue, check the wiring connections and make sure that the CDI is properly wired according to the wiring diagram.
Why is it important to ground the CDI?
A proper ground connection is essential for the CDI to function properly. Without a good ground, the CDI may generate weak or inconsistent sparks, which can cause the engine to misfire or stall. Always make sure that the CDI’s ground connection is clean, tight, and free of corrosion.
What is the correct air gap for the pickup coil?
The correct air gap for the pickup coil varies depending on the make and model of your dirt bike. Check your owner’s manual or service manual for the correct specifications. In general, the air gap should be between 0.1mm and 0.5mm, or about the thickness of a business card.
Can I wire a CDI from a different make or model of dirt bike?
It is possible to wire a CDI from a different make or model of dirt bike, but it may not work properly or may require modification. Always use a CDI that is designed for your specific make and model of dirt bike, and follow the manufacturer’s wiring diagram and installation instructions.
By following these guidelines, you should now have a better understanding of how to wire a 110cc CDI unit to your dirt bike. Remember to always double-check your wiring connections and follow the manufacturer’s instructions carefully to ensure a safe and reliable electrical system.
