Mixing fuel and adding fuel to a motorcycle engine are two different methods of delivering fuel to the engine, and they are typically used in different types of motorcycles.
Mixing Fuel: This refers to the process of combining fuel (typically gasoline) with oil in a specific ratio before it is added to the motorcycle's fuel tank. This is commonly seen in two-stroke engines, where the oil is required to lubricate the engine components, including the piston and crankshaft. In two-stroke engines, the fuel and oil mixture is usually added to a separate oil tank or mixed directly in the fuel tank. The fuel-oil mixture is then delivered to the engine through the carburetor or fuel injection system. Two-stroke engines are commonly found in smaller motorcycles, scooters, and dirt bikes.
Adding Fuel: This method involves adding only the appropriate type of fuel (such as gasoline) to the motorcycle's fuel tank, without the need for mixing it with oil. This is typically seen in four-stroke engines, which have a separate lubrication system for engine components. Four-stroke engines have a dedicated oil reservoir and use engine oil to lubricate the various parts, usually through an oil pump. The fuel and air mixture is controlled by the carburetor or fuel injection system, and only fuel needs to be added to the tank. Most street motorcycles and larger bikes use four-stroke engines.
It's important to follow the manufacturer's recommendations regarding fuel requirements for a specific motorcycle. Some motorcycles may have specific fuel-oil mixing requirements for two-stroke engines, while others may have a separate oil system for lubrication in four-stroke engines. Using the incorrect fuel or mixing ratios can lead to engine damage or poor performance.