Do you need help installing or troubleshooting a 5 pin CDI ignition system on a Chinese ATV, dirt bike, or scooter? This complete guide will teach you everything you need to know about wiring these common CDI systems.
We’ll provide 5 pin CDI wiring diagrams, explain how to connect everything properly, list wire colors, and help you diagnose issues. With the information below, you’ll be able to get your Chinese machine running in no time.
Table of Contents
What is a 5 Pin CDI System?
CDI stands for Capacitor Discharge Ignition. It’s an electronic ignition system that relies on capacitors and electronics to generate high voltage for the spark plugs.
These systems have largely replaced old mechanical contact breaker points ignitions that wore out frequently. CDI ignitions have no moving parts other than the trigger, so they are very reliable.
On a Chinese ATV, dirt bike, or scooter, the 5 pin CDI takes a 12 volt DC current from the battery and converts it to over 20,000 volts to fire the spark plug when needed.
It does this by charging up capacitors in the CDI box and ignition coil. When triggered, the CDI dumps the stored voltage to the ignition coil primary windings, which steps up the voltage even higher on the secondary windings leading to the spark plug.
The 5 pins on the CDI connector supply power, ground, and signals to control this process. Here is a quick overview of each pin’s function:
- Pin 1 – Ground
- Pin 2 – 12VDC from battery via ignition switch and fuses
- Pin 3 – Trigger signal from AC generator stator
- Pin 4 – Switched 12VDC to ignition coil
- Pin 5 – Tachometer signal
In addition to the CDI box, these 5 pin systems also rely on a few other key components:
- Stator– The AC generator containing windings that output AC voltage to both charge the battery and supply signals to operate the ignition.
- Ignition Coil– Steps up voltage from the CDI to 20kV+ to fire the spark plugs. Needs to match CDI voltage specs.
- Rectifier/Regulator– Converts AC from the stator to DC to charge the battery and power the bike. Usually mounted on the stator plate.
Wiring everything together properly is crucial for getting the spark your engine needs. The next sections will cover how to read 5 pin CDI diagrams, wire colors, installation, troubleshooting, and finding compatible ignition coils.
How to Read a 5 Pin CDI Wiring Diagram?
Many Chinese manufacturers provide 5 pin CDI wiring diagrams like the example below. But if you’re unfamiliar, they can be hard to follow.
We’ll break it down step-by-step:
- The diagram shows the CDI connector on the left and every component that connects to it on the right. Wires are shown linking them together.
- Wire colors indicate the purpose of each connection. Common colors are explained later in this guide.
- The stator plate has 3 wire bundles:
- AC leads going to the rectifier/regulator (typically yellow wires)
- Ground wire (green)
- Trigger signal to CDI pin 3 (white)
- Thick red wire goes from battery positive through ignition switch to CDI pin 2 and ignition coil positive.
- Thin black ground wires link CDI pin 1, ignition coil negative, and engine block.
- Blue tachometer wire connects CDI pin 5 to the tach gauge on the handlebars.
Follow the wires in a continuous path to understand the circuit. Using the diagram along with the wire color explanations below will enable you to install a 5 pin CDI system correctly.
5 Pin CDI Wiring Diagram Color Codes
Many bikes use standard wire colors, but always check the manufacturer diagram for your specific model. Here are some common CDI wire colors:
- Red– Switched 12 volt positive from battery to power the CDI and ignition coil
- Black– Ground wires that connect to frame/engine block
- Green– Trigger signal from the stator AC output
- White– Also sometimes used for trigger signal
- Yellow– Stator AC leads that go to rectifier/regulator
- Blue– Tachometer signal to gauge on handlebars
Solid colors like red, black, or blue are used for constant power, grounds, and fixed signals. Striped wires like white/green or yellow/black are used for individual coil wires in multi-cylinder bikes.
Knowing which wires serve what purpose will help tremendously when installing the CDI and troubleshooting issues. Match up the colors to the diagram for your specific bike.
How to Connect a 5 Pin CDI System?
Follow this complete step-by-step guide to install a CDI system:
Step 1 – Mount CDI Box and Route Wires
Start by mounting the CDI box using the included hardware or zip ties. Make sure it is positioned away from heat and moving parts that could damage it.
Cut lengths of wire needed to reach each connection point. Strip 1/4″ insulation off the ends. Add ring or spade terminals to the CDI box wires.
Route the wiring cleanly along the frame using wire clips or zip ties so wires won’t get pinched or rubbed.
Step 2 – Install Stator and Route Wires
Bolt the stator plate and coils in place on the engine case per the manufacturer procedure.
Route the stator’s three wire bundles along the frame:
- AC output to rectifier (yellow wires)
- Ground (green wire)
- Trigger signal to CDI (white wire)
Step 3 – Connect CDI Ground to Battery Negative
Attach the CDI black ground wire to the negative/ground post of the battery or a bolt/tab on the chassis near the battery. Use a ring terminal and bolt or crimp connector.
This grounds the CDI system through the bike’s frame.
Step 4 – Connect Ignition Coil and Spark Plug Wires
Attach the ignition coil positive (usually red) wire to CDI pin 4.
Then connect the ignition coil output wire to the center terminal of the spark plug cap. Many coils have a separate high voltage lead wire already installed.
Clip the spark plug cap onto the spark plug and torque the spark plug into the cylinder head per engine specs.
Step 5 – Connect Rectifier, Battery, and CDI Power
Attach the stator’s three yellow output wires to the rectifier input. Then connect the rectifier positive to the battery positive terminal.
Run the thick red power wire from the battery positive post through the ignition switch to CDI pin 2.
This feeds battery power through the switch to turn the CDI and ignition coil on and off.
Step 6 – Connect Stator Trigger Wires
Connect the stator’s green or white trigger wires to CDI pin 3.
This sends the signal from the stator required to fire the spark plug at the proper time.
Step 7 – Connect Tachometer (Optional)
For bikes with a tach gauge, attach a wire from CDI pin 5 to the tach input. This displays engine RPM on the gauge.
Double check all connections, turn the ignition on to verify power at the coil, and try to start the engine. Refer to the troubleshooting section below if it does not start.
Typical 5 Pin CDI Wiring Problems
If the engine won’t start with the new CDI installed, here are some common wiring issues to check:
Problem: No spark at all
Solution: Check for 12V at CDI pin 2 with ignition on. If missing, trace power circuit for breaks. Verify ground connection is solid. Check trigger signal wire connections.
Problem: Weak spark
Solution: Ensure thick enough wire gauge is used, check for tight crimped connections, make sure ignition coil resistance matches CDI spec.
Problem: Intermittent spark
Solution: Check trigger connections, inspect stator windings for cracks or burn marks indicating arcing.
Problem: Spark at incorrect time
Solution: Verify correct trigger signal wire connected to CDI pin 3. Adjust stator gap to engine spec needed for proper timing.
Problem: Tachometer not working
Solution: Check tach signal wire from CDI pin 5 for breaks and solid connection at tachometer.
Carefully going through all the wiring and checking for flaws in the connections or damaged components is key to getting a troublesome CDI system working properly.
Compatible 5 Pin CDI Ignition Coils
For the CDI system to generate maximum spark energy, the ignition coil must have the proper primary and secondary winding resistance to match the CDI’s voltage and timing parameters.
Always try to use the coil recommended by the manufacturer if possible. If substituting an aftermarket coil, here are the typical specs to match:
- Primary resistance: 0.18-0.28 ohms
- Secondary resistance: 4.4-6.6K ohms
- Minimum primary voltage: 12V
- Secondary voltage: 20kV or higher
Common replacements include coils from Switch Hitter Racing and SSR. Run a resistance check on any coil before installation to make sure it is within spec.
An ignition coil that is not properly matched to the CDI will usually produce a weak spark or no spark at all.
Pros of 5 Pin CDI Systems:
- More robust and reliable ignition than factory parts
- Simple wiring makes DIY installation feasible
- Improves starting, throttle response, and top end power
- Maintenance free – no contact points to wear out
- Sensible upgrade to get the most from your engine
Cons of 5 Pin CDI Systems:
- Aftermarket CDIs may not exactly match OEM timing specifications
- Require matching the proper ignition coil resistance
- Bad solder joints on wiring can cause intermittent problems
- Advanced troubleshooting requires a multimeter
- Some lower quality CDI modules have durability issues
Conclusion
Installing a high performance 5 pin Capacitor Discharge Ignition system on a Chinese pit bike, ATV, or scooter can greatly improve starting, throttle response, and top end power compared to the stock ignition.
But you need to take care in wiring it up properly. Follow the wiring diagram precisely, use quality connectors, double check grounds and routing, and match the ignition coil resistance to the CDI unit.
Taking the time to wire the CDI system correctly will ensure your ride starts easily and performs to its full potential.
With the diagrams, wire color coding, installation steps, troubleshooting tips, and ignition coil info provided in this guide, you now have everything needed to get your Chinese machine running right.
Ride fast but keep the rubber side down!
