Sprint Filter P08 F1-85 Air Filter for Racing – Triumph Speed 400 (2024–2026) CM267S F1-85

Sprint Filter lists this element for the Triumph Speed 400 because the airbox takes it. The F1-85 is the racing tier of the range, a deliberately open weave built so an engine stripped of every other restriction does not meet one at the filter. The Speed 400 is the opposite proposition: one cylinder, a licence class for riders starting out, a bike for commuting and Sunday back roads. The part fits. Whether it belongs in there is another question, and for most owners the answer is no.

Key Features

• Dry racing-grade polyester: no oil when new, none after a wash
• 85-micron aperture rated for 15,000 l/m²/sec — the highest flow Sprint Filter builds
• Those 85 microns are the gaps in the weave, not the thread it is woven from
• Drops into the series airbox as it stands — no cutting, no spacer, no fuelling change
• Roughly twice as much fabric in the housing as a typical performance element
• Cleaned and refitted rather than replaced; life-of-bike design, two years of cover

A racing part filed under a road bike

This medium was drawn with a race grid in mind. Classes that seal the intake leave the filter as one of the few things a team may still choose, so it is built to obstruct as little as possible — and the price of admission is a wider weave. On a race weekend that pays off: the engine asks for everything and the element is cleaned the same evening. A Speed 400 asks for none of it. A single cylinder of this capacity cannot draw close to the air the medium passes, so the headroom sits unused, while the wider aperture stays wider for every kilometre of traffic, pollen and road grit. Against the standard P08 at 80 microns, the step to 85 goes the wrong way here.

Where the Speed 400 is better served

The same filter for this airbox comes in two other media, both a better fit. The standard P08 runs 80 microns at 5,050 l/m²/sec — a tighter weave, more flow than a road-registered 400 will ever call for, and the version most riders want. The P14 leans the other way, 14 microns at 1,800 l/m²/sec, for dusty commutes, gravel roads and high mileage, where what the fabric keeps out counts more than what it lets through. Tighter retains more and passes less; looser reverses both. That is a decision about conditions, not a ladder. The F1-85 earns its place when a Speed 400 is raced and the rules leave the intake as the only choice left.

Care and cleaning

Servicing CM267S F1-85 means compressed air from the inner, clean face outwards, so the dirt leaves the way it came. Where it sits deeper, warm water and mild washing-up liquid lift the rest; rinse and leave it airy until dry. Heat and flame distort the weave, so never use them. Refit it dry and bare — no oiling stage, nothing to reach a sensor downstream. Full instructions sit in the Downloads tab.

Fitment & Compatibility

Listed for the Triumph Speed 400, model years 2024 to 2026. One part number covers three machines in Triumph's 400 range, all sharing the airbox; the compatibility list gives each its own year span, one starting only in the final year. Check yours before ordering.