Replacing the complete wiring harness of a quad bike might be safer and more durable than repairing individual sections. Let’s focus on how to wire a Chinese 110cc fully auto quad to help those with Chinese-made ATVs rebuild.
If you’re new to wiring, we’ll simplify the process into short, achievable steps below. This procedure will work on 50cc, 70cc, 90cc, and 125cc quad bikes because they have similar electrical architectures. Let’s get started.
Step 1: Remove the Old Wiring
This step is simple, but you need to take note of a few things. First is the starter wire. Don’t remove this old wire because most wiring kits for these auto quads don’t include it.
A damaged ATV with old, broken wiring
The second is the stator. You need to know if your ATV or quad bike has a two-coil or six-coil setup to know which part to order as a replacement. Remove the stator’s side cover to see the coil type in your bike.
Step 2: Order and Inspect the New Quad Wiring Package
The new wiring kit should include these components.
- Rectifier for converting AC from the stator to DC to recharge the battery
- CDI box for discharging current to the coil to fire the plug
- Ignition coil with its wiring
- Spark plug (this quad has a single cylinder)
- Starter relay for turning on the starter motor
- Multi-function handlebar switch for turning headlights on/off, starting the motor, and switching between low and high beams.
A quad bike’s handlebar switch
- Stator (two-coil or six-coil)
- Key switch
- Wiring harness with its connectors
The wiring harness section connecting to the front of the quad should have multiple connectors, including male connector sets with white, blue, and green wires. These should link to the headlights.
The rear end of the harness should have the battery connector, fuse, and tail light connectors, among others.
Step 3: Assemble the Electrical System on a Worktable
The components and wiring harness connectors have plug-and-play joints, so it should be easy to set up the system.
But first, assemble the system on a worktable to understand its layout before mounting it in the quad bike. This process will be easier if you have the quad’s wiring diagram.
A red quad bike
Begin the assembly process with the rectifier, which should have a four-pin connector. Link it to the corresponding connector on the rear of the harness.
CDI Box Wiring
Next, pick the CDI box, which should have a 5-pin connector. Mate it to the corresponding female end on the harness, somewhere in the front section.
Ignition Coil Wiring
The ignition coil is unique because it does not have plastic connectors. Instead, it has a green and black wire with independent metal terminals.
The harness has green and black wires on the front section with female terminals that fit the ignition coil wires. Connect them while matching the wire colors.
Starter Relay Wiring
Wiring the starter relay requires more work because it has a primary and secondary circuit. The component has two bolted connectors at the front for the secondary circuit, which connects to the battery and starter motor.
An ATV’s wiring harness connector with multi-colored wires
Wire the harness’s red heavy-gauge wire with a ring connector to the bolted terminal for the battery connection and hand-tighten the bolt. The other link should connect to the starter, so we’ll revisit it later.
Connect the primary circuit connector to the start switch via a harness connector with green, yellow, and red wires.
How To Wire a Chinese 110cc Fully Auto Quad: Multi-Function Switch Wiring
This handlebar switch should have two female connectors. Connect the 6-pin connector to the corresponding 6-pin male connector. Be careful with the other smaller connector because it matches two male ends on the harness.
ATV controls on the multi-function handlebar switch
This connector should have blue and brown wires. You might not get color-matching wires in the harness because the two matching connectors have red & green/yellow and green & black wire combinations. Hook the cable to the connector with red & green/yellow wires.
How To Wire a Chinese 110cc Fully Auto Quad: Key Switch Wiring
Connect the switch wire to the matching connector on the front section of the wiring harness.
A quad bike’s ignition key switch
How To Wire a Chinese 110cc Fully Auto Quad: Remaining Connectors
After connecting the components, you should only have the two headlight connectors and one foot-brake light connector unused on the harness’s front section.
Step 4: Stator Coil Wiring
We’ve singled out the stator coil wiring from the rest because you must install it in the side cover before connecting it to the harness. In most cases, you won’t use the black (ground) and green/red wires, so remove them from this wiring.
Unmount the old stator from the casing by unscrewing the bolts holding it down, then mount the new stator.
Step 5: Install the Wiring Harness
If the starter motor is faulty, replace it before installing the harness. Next, install the side cover with the stator coil.
An ATV’s starter motor
Layout the assembled wire harness next to the quad bike with the correct orientation (front to rear).
Connect the stator wires to the harness while ensuring you match all colors. After that, hook up the remaining part of the starter relay. Unscrew the nut and insert the starter motor wire with the ring connector into the bolt. Hand-tighten the nut over this connector.
Next, hook up the power connections. Find a suitable ground point on the chassis, such as on the top bolt securing the stator coil’s side cover to the ATV. Tie this ground wire’s ring connector firmly to this point.
Connect the other two terminals to the battery. If faulty, replace the old battery to make the electrical system function smoothly. Tie the cable connectors firmly to the battery terminals.
Step 6: Test the System
Test the system before mounting the entire kit. Spray some fuel into the spark plug hole, mount the spark plug, and connect the ignition coil to it.
These harnesses usually have a safety mechanism to stop accidental engine starting, where you must push the brake pedal or hold the brake lever for current to flow to the starter motor.
An ATV’s ignition and safety mechanism
Find the two terminals that plug into the throttle cable assembly to enable this feature. Press them together manually to bypass the safety mechanism.
With the terminals connected, turn the key on and press the start button. The starter should crank the engine, which should run for a while because we sprayed some fuel inside.
Step 7: Mount the Wiring Harness
Get a bunch of cable ties to hold the wiring harness to the quad bike’s frame. But you can’t mount it as it is. Remove the components to free the wires for easy channeling through the chassis sections.
Follow these steps to mount the harness.
- Take one component out at a time
- Mount this component to the chassis using bolts and nuts
- Route the harness to the electrical part
- Reconnect the cable harness’s connector
Avoid routing the wires near or touching the engine because the heat can burn the insulation. And remember to wire the headlight and brake lights to the harness connectors.
Quad bikes with headlights
Test the system one last time before hitting the dirt.
Wiring a Chinese 110cc fully auto quad bike is a moderately challenging task, but the most critical part is to figure out the layout. Once you understand how to connect these electrical parts, the rest is a walk in the park.
That’s it for this article, and we hope it has been insightful. For all your automotive or electric wiring harness needs, contact Cloom tech.