Sprint Filter P08 Air Filter for Road & Track – Yamaha WR 125R (2009–2017) PM116S

A number plate on an enduro is a compromise the engine pays for. The same 125 that spends its week on sealed roads is out on a gravel track at the weekend, riding in its own haze and in everybody else's, and the only thing standing between that air and the bore is the element in the airbox. Nothing about the exchange is noticeable while it happens, which is exactly the difficulty with it. The Sprint Filter P08 PM116S replaces the paper cartridge in the standard WR 125R box with a dry woven polyester screen, cleaned as often as the riding deserves instead of bought again after every dusty weekend.

Key Features

• Retention measured by Sprint Filter at 93.13 per cent of 100 micron test particles
• Dry woven polyester: 80 micron filtration at 5,050 litres per square metre per second
• A single layer woven from threads of 22 microns upwards — the fabric itself does the filtering
• Around twice the filtering area of other performance filters
• Fits the series airbox as it is: nothing cut, nothing moved, no remap
• Washable and reusable, covered for two years from the date of purchase

The damage that reports late

Fine mineral grit does not stay in the intake tract. What reaches the cylinder meets the oil film on the wall and behaves like a lapping compound between ring and bore, and the wear it causes is spread across thousands of small events rather than one failure. There is no noise, no warning light, no bad afternoon to remember it by. It appears years later as compression lower than the odometer can explain, at a point where the cause can no longer be reconstructed. That is why retention, and not flow, is the number to read first on a bike that leaves the tarmac.

Matching the fabric to the ground

Sprint Filter weaves this element in several media, and the difference between them is a trade rather than a ranking. The P08 sits at 80 microns and 5,050 litres per square metre per second; the water-repellent P037 at 37 microns and 4,500; the P14 at 14 microns and 1,800; the T12 at 7 microns and 560. Each step tighter keeps more out and lets less through. For a 125 that mostly commutes and occasionally turns off the asphalt, the P08 is the right end of that line — and none of them makes a standard WR 125R quicker. The gain is a restriction that starts low and stays low, not a figure on a chart.

Care and cleaning

Nothing here is oiled, so nothing has to be re-oiled. Compressed air from the clean side outwards is the normal service and sends the dust back the way it came. After a genuinely hard season, wash the element in lukewarm water with a mild detergent and rinse until the run-off is clear, then let the PM116S dry through completely in open air — never with heat, never over a flame — before it goes back in. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Yamaha WR 125R, 2009 to 2017. Three further machines of the period were built around this airbox and take the same element, the faired YZF R125 among them; the Fitment tab names them.