Sprint Filter P08 Air Filter for Road & Track – Kawasaki Ninja 400 / EX 400 (2018–2026) PM164S

Few small motorcycles are modified as often as the Ninja 400. Levers, screens, rearsets, exhausts, tail tidies — it is a bike people work on, which also means it is a bike that collects changes with consequences attached. Most intake modifications belong in that category: they alter the volume the calibration was written around, they invite a remap, and they can put the machine outside its homologation. The Sprint Filter P08 PM164S deliberately does none of that. It is a panel element that drops into the standard airbox in the position the original occupies, and everything downstream of it carries on as designed.

Key Features

• Drops into the standard airbox in the position the original occupies — no modification, no remap, no change to homologation
• Polyester threads from ø 22 microns, woven to a calibrated aperture rather than pressed from pulp
• Filtering surface: roughly double that of other performance filters
• A dry medium: it is never oiled, so nothing can migrate downstream onto sensors or throttle bodies
• Warranty: two years from the date of purchase
• Washable and reusable, with compressed air as the normal service

The airbox is part of the engine, not packaging

It is tempting to read an airbox as a plastic box in the way of the intake. It is not. Its volume and the length of the tract feeding it are tuned, the ECU's fuelling assumes them, and the noise regulations the bike was approved under assume them too. Replacing the box with an open cone changes all three at once, which is why that route ends in a dyno session. Changing only the element inside it changes none of them.

What it does change

Two things, both modest and both real. The medium presents roughly twice the filtering surface of other performance filters, so the same volume of air passes through a less crowded path. And because the element is washed rather than discarded, the restriction it presents in year five is the restriction it presented in year one, instead of the slow climb a paper element makes between services. On a bike that is often ridden year-round and sometimes taken to a track day, keeping a known baseline is worth more than a number on a box.

Care and cleaning

The whole service needs a compressor and, occasionally, a bucket. Blow the element through from the clean side outwards; if it has earned more than that, wash it in lukewarm water with a mild detergent and rinse until the water runs clear. Then let it dry fully in air — not with heat and not over a flame, either of which ruins it. It is refitted dry, with no oiling step at any stage, because there never has been. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Kawasaki Ninja 400 (EX 400), 2018 to 2026. The same PM164S element serves eleven machines built around this airbox; the complete list is in the Fitment tab.