On some fuel-injected motorcycles, cracking the throttle (twisting it slightly) when starting the engine is known as the "throttle blip" technique. It is primarily done to ensure a smooth and successful engine start. Here's why it may be necessary:
Cold Start Enrichment: When the engine is cold, the fuel injection system may require an extra dose of fuel to facilitate starting. Cracking the throttle momentarily opens the throttle plate, allowing more air to enter the engine. The increased airflow signals the fuel injection system to provide additional fuel, enriching the air-fuel mixture for a cold start.
Air Intake Clearing: Cracking the throttle can help clear any residual fuel or vapors from the intake system. Sometimes, after shutting down the engine, a small amount of fuel can accumulate in the intake manifold. By opening the throttle, fresh air is drawn into the intake, helping to flush out any lingering fuel or vapors, which can aid in a cleaner start.
Throttle Position Sensor Calibration: In certain fuel injection systems, briefly opening the throttle during start-up can assist in calibrating the throttle position sensor (TPS). The TPS provides feedback to the engine control unit (ECU) regarding the position of the throttle. By cycling the throttle, the sensor can establish the closed throttle position, ensuring accurate throttle response during operation.
It's worth noting that not all fuel-injected motorcycles require or benefit from cracking the throttle during start-up. Some modern fuel injection systems have advanced engine management systems that automatically adjust fuel delivery and air intake based on various factors, including engine temperature and ambient conditions. In such cases, following the manufacturer's recommended starting procedure, which may or may not involve cracking the throttle, is the best course of action.
To ensure accurate information for your specific motorcycle model, it is advisable to consult the motorcycle's owner's manual or contact the manufacturer directly for the recommended starting procedure.