The air filter is an essential component of a dirt bike, as it helps protect the engine from dirt and debris. It's important to replace the filter every 10,000 to 15,000 miles, or when it starts to look dirty. However, the lifespan of a filter can vary depending on the environment and how often you ride. Without an air filter, dirt and debris would enter the engine and cause wear on its internal parts.
This is why it's important to keep your filter clean and in good condition. If you forget to change your air filter or can't afford a new one, it won't damage your bike, but it will be more difficult for air to pass through the filter due to dirt blocking or throttling most pores. Dry bike air filters are usually made of foam, which blocks more particles than paper filters. However, as they get dirty, they can inhibit airflow due to their material density.
Depending on the type of filter you have, a dirty filter can have more drastic effects on your motorcycle. To measure if you need to replace the filter, you should have an idea of how clean it should be. If parts of the screen are no longer visible on the filter, or if you cycle more than 5 times a year, you should clean or replace it every 50,000 miles. Cross-linking opens the pores of the foam and allows air to flow more evenly through it.
To clean your filter, massage oil around it until you get an even coloration before mounting it back onto your bike.