Sprint Filter P08 F1-85 Air Filter for Racing – Triumph Bonneville T120 (2017–2026) PM174S F1-85

A T120 earns its keep on long days: two up, panniers on, hours at a steady throttle with a headwind and a pass in the middle. That matters here for an unromantic reason. Everything a filter fails to hold back arrives as a dose, and a dose is the concentration in the air multiplied by the volume of it that has crossed the element. A machine used for distance pushes far more air through its airbox in a season than one that does short Sunday runs, so it also collects the most of whatever its filter lets past. The Sprint Filter P08 F1-85 is a racing medium with an 85 µm aperture — five microns coarser than the 80 µm standard P08.

Key Features

• 85 µm at 15,000 l/m²/sec — roughly three times what the standard P08 passes
• What pays for it is retention: 85 µm holds back less than the 80 µm road medium
• A filtering surface roughly double that of other performance filters
• Dry racing polyester, no oil in it — no film to migrate onto sensors or throttle bodies
• Standard airbox, standard fitment: nothing modified, nothing remapped
• Compressed air from the clean side is the whole service; washable and reused

Contamination is a dose, not an event

Nothing dramatic happens in the second a particle slips past a filter. Wear from ingested dust is cumulative, silent and announced by no warning light; it appears years later as compression, oil consumption and a cylinder head on a bench. What governs it is not how dirty one ride was, but how many cubic metres of air have crossed the medium since the bike was new. On a motorcycle bought for distance that figure is large, and it multiplies whatever fraction the weave does not retain.

Where the extra flow would have to be earned

Against 5,050 l/m²/sec for the standard P08, the PM174S F1-85 is rated at 15,000. Capacity like that only becomes useful when an engine asks for air at the very top of its ability to swallow it: wide open throttle, high revs, held there. A torque-led parallel twin at touring pace sits at the other end of that scale for whole days at a time, so the filtration penalty is paid continuously while the flow benefit is collected almost never. For the intake side of a T120 the P08 at 80 µm and 5,050 l/m²/sec is the road-and-track medium; where the route involves dust, the P14 at 14 µm and 1,800 l/m²/sec trades the other way. Finer holds back more and passes less — a trade, not a ranking.

Care and cleaning

Compressed air does the work: hold it to the clean side and blow outwards, so what the element caught leaves the way it came in. What the air line will not shift comes off with water and a mild detergent — rinse until the water runs clear. Drying is open air only, with no heat and no flame, and the PM174S F1-85 goes back into the box dry. Nothing is oiled.

Fitment & Compatibility

Made for the Triumph Bonneville T120, 2017–2026. The same element covers five machines built around this airbox — the Bonneville T100 and T120, the Street Cup, the Street Scrambler and the Street Twin. The maintenance sheet is in the Downloads tab, the full model-year list in the Fitment tab.