Air Cleaner also called air filter. It is an essential part for the engine. When working properly, an air filter traps dirt and other particulate matter, preventing the same from entering into your engine. When an air filter is clogged or dirty, it can affect engine performance and fuel economy. How Often Should You Replace Air Filters The air filter in a motorcycle should be replaced every 12,000 miles (20,000 kilometres). In addition, the air filter should be checked during every motorcycle servicing period. That is, checking and inspecting the air filter (air cleaner) every 3000 miles (5000 kilometres) of distance traveled. Within the air cleaner, only the filter screen should be replaced since filter is the one that will be clogged from time to time.