When you push or bump start a motorcycle, you are essentially using the rotational energy generated by the movement of the motorcycle to turn the engine's crankshaft, which in turn helps initiate the combustion process. This method is commonly used when the motorcycle's battery is low or the starter motor is not functioning properly.
Here's what happens in the engine when you push start a motorcycle:
Engaging the clutch: Before push starting, ensure that the motorcycle is in a low gear (typically first or second gear) and the clutch lever is pulled in. This disengages the connection between the engine and the rear wheel, allowing the engine to turn freely.
Building momentum: Push the motorcycle to gain enough speed. The idea is to generate sufficient rotational energy in the rear wheel, which is transmitted to the engine's crankshaft.
Releasing the clutch: Once the motorcycle is moving at a decent speed (around 5 to 10 mph), release the clutch lever gradually but smoothly. As the clutch engages, it transfers the rotational energy from the rear wheel to the engine, causing the crankshaft to rotate.
Ignition and fuel delivery: As the crankshaft starts rotating, the engine's ignition system and fuel delivery mechanisms become operational. The spinning crankshaft generates the necessary spark to ignite the fuel-air mixture in the combustion chamber, initiating the engine's firing process.
Combustion and engine running: With the fuel-air mixture ignited, the combustion process continues in the engine cylinders. The running engine generates power to propel the motorcycle and drives its various components, such as the transmission and wheels.
It's important to note that push starting a motorcycle is typically a temporary solution, as it bypasses the starter motor. If your motorcycle consistently requires push starting or experiences difficulty starting, it is advisable to have the battery, starter motor, and associated electrical components checked by a qualified mechanic to diagnose and address any underlying issues.