Cracking the throttle when starting the engine on a fuel-injected motorcycle is a common practice, but the reasons for doing so may vary depending on the specific situation and the motorcycle itself. Here are a few possible reasons:
Cold engine: In some cases, especially when starting a cold engine, cracking the throttle slightly can help provide a richer air-fuel mixture, which aids in easier starting. Opening the throttle allows more air to enter the engine, which can compensate for the initially lean fuel mixture at startup.
Choke or enrichener: Some motorcycles have a choke or enrichener lever/knob that helps provide a richer fuel mixture during cold starts. In such cases, cracking the throttle while engaging the choke can enhance the flow of fuel into the engine, facilitating ignition.
Fuel priming: Cracking the throttle before starting the engine can also serve as a way to prime the fuel system. By briefly opening the throttle, you allow the fuel pump and injectors to deliver fuel to the combustion chamber, ensuring a sufficient amount of fuel is available for ignition.
It's worth noting that the specific starting procedure can vary depending on the motorcycle model and manufacturer recommendations. Therefore, consulting the owner's manual or contacting the manufacturer directly can provide you with the most accurate information on the recommended starting procedure for your particular motorcycle.