Sprint Filter P08 F1-85 Air Filter for Racing – Suzuki Katana (2019–2022) PM91S F1-85

Almost everything an owner adds to a Katana can be seen. That is half the point of the motorcycle, and it makes the airbox the odd one out: the air filter is the one change that leaves the outside of this machine exactly as Suzuki drew it. Nothing shows, nobody asks, and the purchase has to stand on what it does rather than how it looks. Held to that standard, the racing version of this element — the P08 F1-85 — has a narrower case than its name suggests.

Key Features

• The racing weave of the P08 family: dry polyester at 85 microns, no oil at any point
• Flow of 15,000 litres per square metre per second, where the road P08 moves 5,050
• A large filtering surface, about twice the media of a typical performance filter
• Swapped in for the original element; bodywork, ducting and mapping stay as delivered
• Cleaned with compressed air and used again, season after season
• Two years of Sprint Filter cover from the purchase date

The one change that does not show

Under the tank this Katana is the GSX-S 1000 of 2016 to 2021: the same intake, the same element, which is why one part number serves both. The decision loses everything a Katana purchase usually turns on: no line, no finish, no sound. There is a weave, a flow figure and a price. And plainly: a drop-in filter does not make a standard motorcycle noticeably stronger, whichever medium it is cut from. What it can do is hold the intake's share of the resistance low and steady between services, and stop being a part bought again every year.

Where 15,000 litres would have to be used

The gap between the two media is flow: 15,000 litres per square metre per second against 5,050, bought by opening the aperture from 80 microns to 85. That capacity exists near the top of the rev range at full throttle and nowhere else, and it is not free: the F1-85 costs about two and a half times the P08 here, and the wider weave is wider on every ride, not only the fast ones. Sprint Filter measures 95.22 per cent retention of 100-micron particles against 93.13 for the P08, but those are coarse; the fine fraction that reaches the oil sits outside the test. If the Katana sees track days and its intervals are counted in hours under load, the trade is fair. Ridden on chosen Sundays and serviced by the book, the standard P08 is the more honest purchase — and dusty routes argue for finer media, P037 at 37 microns or P14 at 14: each holds more back and flows less. Finer is not better, only aimed elsewhere.

Care and cleaning

Compressed air is the routine: aim it at the clean face of the PM91S F1-85 and push outwards until the weave is open. A wash in lukewarm water with a mild detergent handles the rest; rinse it clear, then dry it fully in open air, with no heat gun and no flame near it, and refit it dry. The maintenance sheet sits in the Downloads tab.

Fitment & Compatibility

For the Suzuki Katana of 2019 to 2022, seated in the standard airbox with nothing else altered. This racing element covers two machines, the Katana and the GSX-S 1000 of 2016 to 2021; the 2022-onwards Katana takes a different one.