Sprint Filter P08 F1-85 Air Filter for Racing – Triumph Speed Twin 900 (2023–2026) PM217S F1-85

Some parts deserve a question before they deserve a purchase, and this is one of them. The P08 F1-85 is Sprint Filter's racing medium: a dry polyester weave with an 85 µm aperture that flows 15,000 l/m²/sec, against 5,050 l/m²/sec for the standard P08. That is roughly three times the airflow capacity, and it is bought with filtration rather than granted for free — the standard P08 filters to 80 µm, and this one deliberately does not. The Speed Twin 900 is a road motorcycle with a mild, torque-led parallel twin. None of that makes the part wrong.

Key Features

• 85 µm filtration at 15,000 l/m²/sec — no woven medium in the Sprint Filter range flows more
• That is coarser than the 80 µm of the standard P08: the extra flow is paid for in filtration, openly and by design
• A racing medium that is nevertheless dry — never oiled, so nothing migrates downstream onto sensors or throttle bodies
• Standard airbox, direct replacement: nothing modified, nothing repositioned, nothing remapped
• Serviced with compressed air instead of being thrown away; washable and reusable
• Two years of warranty, running from the date of purchase

Three questions to answer before ordering

First: is this engine opened on a schedule of operating hours? Race teams accept a coarse medium because the top end comes apart often enough that anything which slipped past the filter is found long before it becomes expensive. Second: does the bike run on a circuit? Third: how many of last year's kilometres were ridden near the red line? A 900 cc twin geared and mapped for the road spends almost its entire life well below the point at which any air filter is the limiting element.

If the answers point somewhere else

Then the honest recommendation is a different medium on the same part number, not a different brand. The standard P08 filters to 80 µm at 5,050 l/m²/sec and was developed for exactly this mixture of everyday road riding with the occasional track day. Where the roads are dusty or unsealed, the P14 goes the other way — 14 µm at 1,800 l/m²/sec, far more retention and far less flow. A finer weave holds more and passes less; that is a trade, not a ranking. The F1-85 earns its place only where the maintenance regime behind the engine justifies the filtration it gives up.

Care and cleaning

In the paddock this needs an air line and nothing else: clean side, blown outwards, so that whatever the element caught leaves the way it came in. Water with a mild detergent is the deeper option for what the compressor leaves behind; rinse until the water runs clear. The PM217S F1-85 then dries fully in open air, never with heat and never with a flame, and it goes back dry — nothing is oiled at any point in its life. The maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Triumph Speed Twin 900, 2023–2026. The same element covers five machines built around this airbox — the Speed Twin 900 and Speed Twin 1200, and the Thruxton 1200 in R, RS and TFC form. The full list with model years is in the Fitment tab.