Sprint Filter P08 F1-85 Air Filter for Racing – Kawasaki Z400 (2018–2026) PM164S F1-85

A great many Z400 end up as something other than what left the factory — stripped for track use, rebuilt as street trackers, or simply modified hard and then sold on to somebody who wants a standard motorcycle again. That last step is where a lot of modifications turn into a problem, and it is worth knowing which ones do not. The Sprint Filter P08 F1-85 is a racing medium that lives entirely inside the standard airbox: 15,000 l/m²/sec of air flow at a filtration of 85 microns, with nothing about the box, its lid, its inlet or its mounting altered to accommodate it.

Key Features

• The standard airbox takes it unchanged — no modification, no remap, nothing declared
• Never oiled, and dry throughout; nothing can travel downstream onto the sensors
• Racing medium: 15,000 l/m²/sec of air flow, filtration to 85 microns
• Washable and reusable; compressed air from the clean side is the service
• Filtering surface roughly doubled against other performance filters
• Warranty: two years, on an element designed to last the life of the bike

Reversible, and therefore easy to live with

Because the change is internal, it leaves no trace on the outside of the motorcycle and nothing that has to be undone with tools beyond the ones needed to open the airbox. A bike being returned to standard for sale takes its original element back in an afternoon; a bike being prepared for a track season takes the racing one just as quickly. Rules on modification differ by market and the responsibility stays with the owner, but the factual position is simple: this is a fabric inside a standard box, not a change to the box. Which is also an argument for keeping the original element rather than discarding it. The Sprint Filter is designed to last the life of the motorcycle, so the standard one will never be needed as a spare — only as the way back, and a Z400 returned to standard specification is an easier motorcycle to sell than one that is nearly standard.

What the racing medium gives and takes

The flow figure is genuinely large — about three times the standard P08's 5,050 l/m²/sec — and a standard Z400 has no way to use it. The filtration figure moves the other way: 85 microns against the P08's 80, a coarser weave accepted because racing engines are inspected often. On a road-ridden Z400 that trade is being made without the maintenance that justifies it, and the standard P08 is the better part. The F1-85 belongs on a Z400 that has been built for the circuit and is serviced accordingly.

Care and cleaning

Compressed air from the clean side, worked outwards, then refit dry: that is the service, every time. Water is for the end of a season — lukewarm, a mild detergent, a rinse until it runs clear, then a full air dry, never with heat or a flame. The medium is not oiled, so there is no step to repeat afterwards. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Kawasaki Z400 from 2018 to 2026. The same PM164S F1-85 element covers eleven machines sharing this airbox; the complete list is in the Fitment tab.