Carbureted motorcycles have a choke because the choke helps provide a richer fuel mixture during cold starts. When an engine is cold, it requires a higher ratio of fuel to air in the combustion chamber for efficient combustion. The choke restricts the airflow into the carburetor, creating a stronger vacuum and drawing more fuel into the mixture. This helps compensate for the reduced vaporization of fuel due to lower temperatures, ensuring that the engine starts and runs smoothly.
On the other hand, fuel-injected motorcycles use an electronic fuel injection system to deliver the precise amount of fuel required for efficient combustion in various operating conditions. The electronic control unit (ECU) constantly monitors factors like engine temperature, air intake, throttle position, and more to determine the optimal air-fuel mixture for combustion.
During cold starts, the ECU automatically adjusts the fuel injection parameters to provide a richer mixture without the need for a separate choke mechanism. It achieves this by increasing the duration or volume of fuel injection to compensate for the lower temperatures. The ECU takes care of these adjustments based on the sensor inputs, allowing fuel-injected motorcycles to start smoothly without the rider needing to manually operate a choke.
Overall, the transition from carbureted to fuel-injected systems in motorcycles has improved the efficiency and performance of engines, eliminating the need for a choke and providing more precise control over the air-fuel mixture.