Sprint Filter P08 F1-85 Air Filter for Racing – KTM 990 Duke (2024–2026) PM175S F1-85

One housing has carried this family from the 790 through the 890 to the 990, and Sprint Filter has never had to draw a second element for it. What changed across those three engines is how much air is asked of the same aperture in a minute. If there is any machine on this list where the highest-flowing medium is not simply an expensive answer to a question nobody asked, it is this one, the largest of them — and even here the case rests on conditions that public roads do not supply.

Key Features

• Dry polyester racing weave rated 85 µm, flowing 15,000 l/m²/sec
• The highest flow rate of any medium catalogued for this airbox
• Roughly three times the rate of the standard P08, which is specified at 5,050
• Seated in the unmodified series airbox in place of the standard element
• Cleaned dry with compressed air and never oiled at any stage of its life
• Two years of cover from purchase, and a life measured against the motorcycle

One box, three engine sizes

The aperture did not grow when the engine did, twice. That is normal engineering practice and it says something useful about where the margin sits: a housing specified around the smallest member of a family has reserve to spare on that machine and progressively less on the later, larger ones. Whatever headroom is left over is smallest on the 990, which is why this is the only place in the family where a higher-rate medium can be discussed without embarrassment.

What a flow rating is measured on

It is a property of the cloth, per square metre of it, and it is measured on the cloth. What an engine actually receives is settled by everything between the intake mouth and the valve — duct, plenum, throttle bodies, camshaft timing — and no single one of those is put right by improving another. So the 15,000 figure describes a capability of the medium, not a promise about the machine. A replacement element does not make a standard 990 Duke quicker; that is true of every element in this housing, this one included.

Care and cleaning

An air line does nearly everything: apply it to the clean side, work outward, and stop when the weave stops releasing anything. Greasy loading calls for lukewarm water and a mild detergent, rinsed through until the water runs clear. After that the PM175S F1-85 dries in moving air, at its own pace, with no heater and no flame anywhere near it, and it is refitted dry and untreated. The maintenance sheet is filed in the Downloads tab of this page.

Fitment & Compatibility

The P08 F1-85 for the KTM 990 Duke, model years 2024 to 2026. Five machines qualify through a shared airbox that dates back to 2018, so the element code and the year identify the part rather than the model name. The same housing also takes the standard P08 and two finer media. The full list is in the Fitment tab.