Sprint Filter P08 Air Filter for Road & Track – Honda CB350RS (2020–2026) SM289S

The RS wears block-pattern tyres and sits its rider more upright than the roadster it is based on, and owners take that invitation seriously. It is not an off-road machine, but it sees farm tracks and unsealed mountain roads far more often than the rest of the family does. Dust is what that costs, and dust keeps a calendar of its own: a fortnight of dry gravel can load an air filter harder than a year of wet tarmac. That is the argument for the Sprint Filter P08 SM289S on this particular version — not more power, which a drop-in element cannot honestly promise, but an element that can be blown out at the end of a dusty week and put straight back in.

Key Features

• Minutes with a compressor and it is done — no oiling kit in the luggage, no drying time to plan a trip around
• Dry polyester, oil-free by construction, so no film can work its way downstream onto the sensors
• Threads of ø 22 microns and upwards, woven to a calibrated aperture rather than pressed into a mat
• Roughly twice the filtering area other performance elements offer
• Fits the standard airbox as it stands: nothing modified, nothing remapped, homologation as Honda left it
• Built to remain the motorcycle’s filter for its whole life

Why oil is the wrong answer in dust

Oiled cotton gauze works by making dirt stick, which is effective right up to the point where the tacky surface holds more than it can carry. From then on the trapped layer is the filter, flow falls away, and the oil carried into the intake tract has to end up somewhere — usually on the sensors the injection system relies on to meter fuel. The P08 traps by geometry instead: threads from ø 22 microns woven to a calibrated aperture, rated at 80 microns and 5,050 l/m²/sec. Sprint Filter’s comparison puts it at 93.13 % retention of 100 micron particles against 76.42 % for four-layer oiled cotton. Nothing is added to the medium, so nothing can leave it.

When the dust is permanent rather than occasional

There is an honest limit to draw. If the RS lives mostly on sealed roads and only occasionally leaves them, the P08 is the right medium: road and track specification, flow kept high. If it works in genuinely dusty conditions week after week, Sprint Filter makes finer media for that — the P14 at 14 microns, the T12 at 7 microns for extreme ground. They hold back far more and flow correspondingly less, 1,800 and 560 l/m²/sec against 5,050. A trade, not a ranking.

Care and cleaning

After a dusty run, compressed air from the clean side outwards is usually all the SM289S wants. Give it a wash once the dust has turned to grime: lukewarm water, mild detergent, rinsed until the water runs clear, then dried out in open air and nowhere near heat or a flame. It goes back only once it is dry through, and exactly as it is: nothing is ever oiled onto this medium. The maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Honda CB350RS from 2020 to 2026. The same SM289S element covers five machines built around the same 350 cc single; the complete list is in the Fitment tab.