Your motorbike engine will have air passing through it as it is running. This air however, is not clean and contains a number of contaminants including dust, dirt and sand.
The air filter on a motorbike protects the engine from the particles present in the air which could make their way into the engine and block up the working parts.
This can cause poor performance and additional wear resulting in more expensive running costs.
The air filter also enhances airflow in the engine to provide more efficient acceleration and horsepower.
Nearly all models of bike have air filters and you can get special replacement aftermarket performance air filter options to improve performance.