How do you tune a Weber twin barrel carburetor?

To tune a Weber twin barrel carburetor, start by adjusting the idle mixture screws on each barrel for a smooth idle, turning them in or out until the engine runs evenly. Next, balance the airflow between the barrels using a synchronizer tool, ensuring both barrels open simultaneously. Adjust the float level to ensure proper fuel delivery and check the main jet size for optimal performance under load. Finally, test drive the vehicle and make fine adjustments as needed for throttle response and overall performance.