The invention relates to an air-intake system for an internal combustion engine (10) equipped with an air filter which comprises, inside an air filter housing, an uncleaned air chamber, a clean air chamber that is connected to the internal combustion engine (10), and comprises a filter insert that is arranged between the uncleaned air chamber and the clean air chamber. The uncleaned air chamber is subdivided by a partition (22) into an uncleaned air admission volume (24) and a uncleaned air discharge volume (26), whereby the size of a cross-section of the opening which is situated on the partition (22) and which is provided for the passage of uncleaned air from the uncleaned air admission volume (24) into the uncleaned air discharge volume (26) can be varied.