Sprint Filter P08 F1-85 Air Filter for Racing – Brixton Crossfire/X (2017–2026) CM136S F1-85

Fifteen thousand litres per square metre per second is a great deal of flow, and it was drawn for engines that can ask for it. A 500 cm³ parallel twin in a road frame is not going to. That is the honest starting point for this page, because it means the reason to buy CM136S F1-85 for a Crossfire/X is not the flow headroom at the top of the specification — it is the retention figure underneath it.

Key Features

• Dry woven medium at 85 microns, rated at 15,000 l/m²/sec
• 95.22 % retention measured on 100-micron particles
• Never oiled: dry when supplied, dry again after every cleaning
• Direct fit in the standard Crossfire/X airbox — nothing cut, nothing remapped
• Around twice the filtering surface of a conventional flat element
• Washable and reusable, with two years of warranty from the purchase date

Headroom you will not spend

An element cannot deliver more air than the engine behind it draws. On a machine of this displacement the standard weave, rated at 5,050 l/m²/sec, is already ahead of the demand, so tripling the number on the data sheet does not translate into anything the rider meets on the road. It is worth saying plainly rather than letting the largest figure in the catalogue do the talking: in an unmodified airbox this element leaves a standard Crossfire/X exactly as strong as it was, and the racing designation describes the medium, not a result.

What is actually being bought

The measured retention is the part that survives the argument. At 95.22 % on the 100-micron test, this medium holds more than the 93.13 % of the standard weave, and both figures come from the same test rather than from two different ones read side by side. For an owner that is a straightforward proposition: the same dry, washable construction, the same absence of oil near the intake sensors, and a slightly more selective screen. Whether that is worth roughly two and a half times the price of the standard element is a decision, not a recommendation — and it is a decision this page would rather have made with the right number in view.

Care and cleaning

Compressed air held against the clean face of the CM136S F1-85, worked outwards, is the routine service. When air stops being enough, lukewarm water with a mild detergent finishes it; rinse until the water runs off clear. Drying is done in moving air at room temperature and by no other means, since heat damages the weave long before anything looks wrong. Refit it dry, with nothing applied. Sprint Filter's maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Brixton Crossfire/X of 2017–2026, fitted in the series airbox without modification. This code covers two machines, the Crossfire/X and the Gaokin Flame that shares the housing. Confirm your build year in the Fitment tab.