Der atmosphärische Druck diffundieren vom hohen Druck bis zum niedrigen Druck. Wenn sich der Kolben eines zweitaktuellen Motors in der obersten Mitte befindet, entwickelt sich unter dem Kolbengeschäft ein niedriger Druck unter dem Kolben. Gleichzeitig verursacht dieser niedrige Druck auch einen niedrigen Druck im Vergaser. Because the pressure outside the engine and carburetor is higher, air will rush through the carburetor and into the engine until the pressure is equalized. The air flowing through the carburetor will carry the fuel, and the fuel will mix with the air.
The throat is the constricted section inside the carburetor that forces air to accelerate through it. Accelerating the flow of air will cause the atmospheric pressure inside the carburetor to drop. The faster the air flow, the lower the pressure inside the carburetor. By placing a tube in the throat, we can use low pressure to mix fuel into the airflow.
Most motorcycle carburetor passages are controlled by throttle position rather than engine speed. There are five main adjustment systems in most motorcycle carburetors. These adjustment systems affect each other, they are: idle channel, idle jet, main nozzle and oil needle, main jet, choke channel.
Even after tuning is done and the motorcycle is running well, there are many factors that can change the performance of an engine. Altitude, air temperature and humidity are important factors that affect engine operation. Air density increases when the air is colder. This means that when the air is cold, there are more oxygen molecules in the same space. As temperatures drop, the engine will run leaner and more fuel must be added to compensate. When the temperature is warmer, the engine will run richer and the demand for fuel will decrease. An engine tuned at 32 degrees Fahrenheit may not run well when the temperature reaches 90 degrees Fahrenheit.
Altitude will affect engine tuning since air molecules decrease as altitude increases. Because less air enters the carburetor. A motorcycle that works well at sea level at 10,000 feet will run with a richer mixture.
Luftfeuchtigkeit ist die Wassermenge in der Luft. Wenn die Luftfeuchtigkeit zunimmt, ist die Mischung dicker. Ein Motorrad, das morgens in der trockenen Luft gut läuft, verläuft am nächsten Tag in einer reicheren Luftmischung, wenn die Luftfeuchtigkeit zunimmt.