Sprint Filter P08 F1-85 Air Filter for Racing – KTM 790 Duke / L (2018–2020) PM175S F1-85

It is a natural assumption that the dearest element in a range is the finest one. On this airbox the assumption is almost exactly inverted. Ordered by filtration the four media run T12 at 7 microns, P14 at 14, the standard P08 at 80 and this one at 85 — and ordered by price they run very nearly backwards, with the two finest media the cheapest of the four, the standard weave above them, and the F1-85 at roughly two and a third times what the P08 asks for the same housing.

Key Features

• Racing-specification dry polyester: 85 µm filtration at 15,000 l/m²/sec
• Close to three times the flow rate of the standard P08, which passes 5,050
• Retention measured at 95.22 %, against 93.13 % for the standard weave
• No oil at any point, so nothing can migrate forward onto the throttle bodies
• Fits the standard 790 airbox with nothing cut and no remapping required
• Washed and refitted rather than replaced; two years of warranty from purchase

The price list is not a filtration ladder

What a medium costs is a statement about the cloth and the process that makes it, and about the market it was drawn for. It is not a grade. The extreme nonwoven at the bottom of the price column filters an order of magnitude finer than the weave at the top of it, and a buyer who works down the list expecting quality to follow money will end up with a part chosen by accounting rather than by air. That is the single most useful thing to know before comparing the four elements offered for this housing.

Which one a 790 should have

The standard P08 in nearly every case. This is a road machine of a certain age, and the additional rate the F1-85 makes available is collected only at full throttle high in the rev range, which is a small number of seconds in any ride. It will not make either version of the 790 quicker in any case, and on the A2-restricted L the ceiling belongs to a licence category that no intake part can go near. The PM175S F1-85 earns its place where the machine is used in competition and the element is inspected accordingly.

Care and cleaning

Compressed air held to the clean face and driven outward is the whole of the routine, and on a racing weave it is quick, because the medium gives its load up readily. Water and a little mild detergent deal with anything greasy; rinse until the water leaves clear. Drying takes place in open moving air only — heat is what destroys polyester, so no guns, no radiators, no flame — and the element is refitted dry and with nothing applied to it. The maintenance sheet is in the Downloads tab.

Fitment & Compatibility

The P08 F1-85 for the KTM 790 Duke and 790 Duke L, model years 2018 to 2020. Five machines are listed against this code, all of them sharing one airbox across three engine sizes. Because the housing takes four different media, the element code identifies the medium as well as the fitment. Order by code and model year; the full list is in the Fitment tab.