Upgrading Performance: Gy6 Carburetor To Fuel Injection

Replacing a carburettor with a fuel injection system is a critical process for improving fuel efficiency and performance. This process involves removing the carburettor and fuel lines, installing injectors, a throttle body, sensors, and adjusting the distributor and electronics. It is important to ensure that the engine and fuel system are clean and that the fuel is fresh before beginning any work. Additionally, it is recommended to have a basic understanding of the entire process and relevant experience for a smoother experience.

Remove the carburetor

To remove the carburettor, you will need to take off the fuel lines and hoses that are connected to it. The carburettor is mounted to the manifold by nuts, so use a wrench to remove these and take the carburettor off. If it is in good condition, you can sell it as a used part. If not, take it to a junkyard.

Before you begin, it is important to make sure that your carburettor and fuel system are clean, the fuel in your tank is fresh, the air filter or air box is attached and in good condition, and that the vacuum and fuel hoses are properly connected and not damaged or cracking.

You will need to drain the bowl, disconnect the fuel hose, throttle cable, vacuum hoses, unhook the choke or enricher/bystarter, and disconnect the oil injection hose if your vehicle has one. Then, remove the carburettor from the air box or filter and the intake. Once the carburettor is removed and the fuel has been drained, you can remove the float bowl by taking out the screws that hold it in place. There are usually three or four screws around the perimeter of the bowl, but some aftermarket carburettors use a large central plug/screw to keep the bowl in place.

If you need to adjust the float height, there is often a metal tab/tang on the float assembly that the float needle hangs from. Bending that tab will allow you to change the float height. Take small steps and be gentle with the tab until you reach the desired height. Some floats are solid plastic and not easily adjustable. If you must adjust the float height and have a plastic tab, first see if you can change the height by bending the hangar on the float needle. If not, you may be able to heat the plastic tab enough that it can be bent. Do not use an open flame, but instead something like a hairdryer or heat gun. You must be careful, as plastic floats can easily be melted and ruined.

If you have a vacuum-operated fuel petcock, it may take a few seconds of cranking or kicking the engine over to allow fuel to fill the bowl between jet changes so that the engine can start. Some prefer to disconnect the vacuum line leading to the petcock and apply mild suction before cranking the engine over so the bowl can fill more quickly. Don't forget to replace the hose afterward. The process is much simpler with a manual fuel shutoff, and the bowl should refill within seconds after turning the fuel supply on after a jet swap.

Install the injectors

The next step in the process of replacing a carburetor with fuel injection is to install the injectors in the intake manifold. This step will involve welding, so it may be necessary to bring the vehicle or parts to a machine shop. Most intakes can be modified using weld-in bungs for injectors. Once the injector spot is available, the injectors can be slid into place with O-rings for the seal.

It is important to note that injection fuel rails are also necessary but will need to be machined. Depending on the type of conversion kit, it may come with a ready-to-go manifold that accepts injectors. Many companies also produce ready-to-go injector manifolds. It is recommended to use these ready-made options to simplify the process.

When installing the injectors, it is crucial to ensure proper sealing to avoid fuel leaks. The O-rings play a vital role in creating a tight seal, so make sure they are in good condition and installed correctly.

Additionally, the placement of the injectors should be precise to ensure optimal fuel delivery. It is advisable to refer to the vehicle's service manual or seek guidance from a professional mechanic to ensure the injectors are positioned correctly.

Before proceeding to the next step, it is essential to verify that the injectors are securely installed and that there are no fuel leaks. A thorough inspection and testing of the injectors' functionality will help ensure a successful conversion.

Once the injectors are in place and functioning correctly, you can move on to the next step of installing the throttle body, which regulates the air entering the valves.

Install the throttle body

To install the throttle body, you will need to bolt the throttle body onto the engine and hook it up at the throttle linkage. This is connected to the accelerator pedal.

An idle air controller (IAC) is needed with the EFI throttle body. This goes into a small passage that pushes extra air past the throttle plates. It opens or closes the passage depending on how much air is needed in the manifold. Most throttle bodies come with an IAC already installed.

Universal models are the easiest for conversions.

There are also throttle body EZ-EFI kits available. These are carb-replacement systems that support stock-to-650 HP engines. They feature a setup wizard that guides you through start-up and tunes itself as you drive.

Install the sensors

To install the sensors for your new EFI system, you will need to refer to the installation manual for your specific kit. However, here is a general step-by-step guide on how to install the sensors, followed by a list of the sensors you will need to install:

Step-by-Step Guide:

• Identify the sensors included in your EFI kit.
• Locate the areas on your bike where the sensors will be installed. Refer to your bike's service manual or consult a mechanic if you are unsure.
• Prepare the sensors for installation. This may include tasks such as cleaning the sensors, applying thread sealant, or attaching wiring connectors.
• Mount the sensors securely in their designated locations, following the instructions provided with your EFI kit.
• Connect the sensors to the EFI system's wiring harness. Ensure that all connections are secure and waterproof, if necessary.
• Test the sensors to ensure they are functioning correctly. This may involve starting the engine and monitoring the sensor readings on a diagnostic tool or laptop connected to the EFI system.

Sensors to Install:

• Throttle Position Sensor (TPS)
• Oxygen (O2) Sensor
• Manifold Absolute Pressure (MAP) Sensor
• Engine Coolant Temperature (ECT) Sensor
• Intake Air Temperature (IAT) Sensor
• Crank Position Sensor (CKP)
• Atmospheric Pressure Sensor

Note: This is a general guide, and the installation process may vary depending on the specific EFI kit you are using. Always refer to the instructions provided with your kit for the most accurate and safe installation procedure.

EFI Kit Sensors:

When installing an EFI kit, you will typically need to install several sensors that work together to ensure optimal engine performance. Here is a list of sensors that are commonly included in EFI kits for the GY6 engine:

Adjust the distributor

Adjusting the distributor is a critical step when replacing a GY6 carburetor with fuel injection. Here is a detailed guide on how to go about it:

Understanding the Distributor's Role:

The distributor in an engine plays a crucial role in managing the ignition timing and advance. It ensures that the spark plugs receive the electrical current from the ignition coil at the right moment, allowing for precise combustion and engine performance.

Locking Out the Distributor:

When switching to an electronic fuel injection (EFI) system, the ignition timing and advance become controlled by the new EFI system. Therefore, you must lock out the distributor to prevent it from interfering with the EFI's timing control. This involves disabling the vacuum and mechanical advance functions of the distributor. Most distributors will work effectively with a bank-to-bank EFI system. However, if you are using sequential fuel injection, you may need to upgrade to a dual sync distributor.

Setting the Initial Timing:

Before locking out the distributor, it is essential to set the initial timing correctly. This process involves adjusting the distributor so that the spark plugs fire at the optimal moment in relation to the piston's position. You will need a timing light to perform this task. Connect the timing light according to the instructions, and then follow these steps:

• Start the engine and let it idle.
• Point the timing light at the timing marks on the crankshaft pulley.
• Adjust the distributor housing until the timing mark aligns with the desired timing degree, typically specified in the vehicle's service manual.
• Tighten the distributor clamp once the correct timing is set.

Checking and Adjusting the Vacuum Advance:

The vacuum advance is a mechanism that adjusts the ignition timing based on engine load and speed. It is crucial for optimal engine performance and fuel efficiency. To check and adjust the vacuum advance:

• Locate the vacuum advance unit on the distributor.
• Connect a vacuum gauge to the unit and start the engine.
• Rev the engine and observe the vacuum reading. Adjust the vacuum advance screw until you achieve the recommended setting, usually specified in the vehicle's service manual.

Finalizing the Setup:

Once you have locked out the distributor, set the initial timing, and adjusted the vacuum advance, it is time to finalize the setup. This involves connecting any necessary sensors and ensuring that the EFI system is correctly configured and calibrated. Refer to the EFI system's instructions for specific details on completing the installation and initial setup.

Adjusting the distributor is a delicate process that requires a good understanding of engine mechanics and EFI systems. If you are unsure about any steps, it is always best to consult a professional mechanic or seek advice from a trusted automotive forum.

Frequently asked questions