Sprint Filter P08 F1-85 Air Filter for Racing – Royal Enfield Bullet Trials 500 EFI (2011–2026) CM195S F1-85

The gap between 5,050 and 15,000 l/m²/sec is real, published and easy to quote. What it is not is something a rider can detect from the saddle of a standard motorcycle. Intake restriction on a series machine sits behind a throttle body, an exhaust and a fuel map that were all specified around the paper panel, and a change upstream of that chain shows up on instruments long before it shows up in an impression. The CM195S F1-85 is a racing element, and racing is where such a difference is measured rather than felt.

Key Features

• Racing polyester medium, dry, with 85 µm filtration
• 15,000 l/m²/sec of rated flow — the highest figure in the Sprint Filter media range
• Retention measured at 95.22 % of 100-micron particles in the manufacturer's comparison
• Roughly double the filtering surface of other performance elements, inside the standard box
• No oil, no remap, no airbox modification: it replaces the factory panel as it is
• Washable, reusable, two years of warranty from the date of purchase

Measured, not felt

By Sprint Filter's own account, this is the most widely used air filter in MotoGP, Moto3, World Superbike, Supersport and Superstock — a manufacturer's statement about use rather than an independent measurement, and worth reading as one. What a team draws from a washable element is repeatability: the same known intake condition at the start of every session, restored with an air line instead of a parts order. On a road-registered Trials none of that apparatus exists, and the honest position is that the extra capacity goes unused.

What it costs to find out

This element runs to about three and a third times the standard P08 for the same airbox, and roughly three times the fine P14. That is not a small experiment, and it is not one to encourage on a standard machine: a drop-in filter does not make a series motorcycle noticeably stronger, and buying more flow than the engine draws changes nothing except what you paid. The standard weave is the sensible rung here; this one earns its place on a bike used on track.

Care and cleaning

Compressed air from the clean side, moving steadily across the face of the CM195S F1-85, is the whole routine for dry dirt. Anything greasy comes off with lukewarm water and a mild detergent, thoroughly rinsed afterwards. The element then dries in open air, never with heat and never over a flame, and returns to the box with nothing applied to it. Full maintenance instructions are in the Downloads tab.

Fitment & Compatibility

Listed for the Royal Enfield Bullet Trials 500 EFI from 2011 to 2026, alongside three further machines on the same number: the Bullet B5 500 EFI across those model years, the Classic 500 of 2009 to 2020, and the Continental GT35 EFI, 535 cm³, of 2015 to 2018. Check your year in the Fitment tab.