Sprint Filter P08 Air Filter for Road & Track – Moto Guzzi V7 IV Stone (2021–2026) PM138S

The fourth-generation V7 took the 853 cc engine out of the V9 and put it into the smaller chassis, and the model designation rather undersells what that did. There is noticeably more torque everywhere, and the bike will now sit at a motorway speed without giving the impression it is being imposed upon. One thing did not change with the engine: the airbox. The same case, the same aperture, the same panel — which is exactly why what goes into it is worth a moment's thought on this generation.

Key Features

• Dry polyester medium with an 80-micron aperture; 5,050 l/m²/sec on the bench
• No oil at any stage, so nothing exists that heat or airflow could carry downstream
• Filtering area roughly twice that of a conventional performance panel
• Sits in the unaltered series box; the engine management is left untouched
• Cleaned and refitted rather than consumed, across the life of the motorcycle
• Two years of manufacturer cover, dated from purchase

More engine, identical opening

Enlarging a motor without enlarging its airbox is an entirely reasonable engineering decision — the box was never the limiting factor and the extra capacity does not need one. But it does mean the panel that was working comfortably on 744 cc is being asked for more air at the same throttle angle on 853. Since pressure drop scales with the volume passing through, the element that was operating at a quarter of its capability is now closer to a third, and it reaches any given state of loading sooner. Area is the only variable available to push back, and it is the one this panel changes.

Where extra area actually shows

Not on a dynamometer, and not on the day it is fitted. It shows in the second half of the service interval, on the bigger engine, under load — the long uphill with a pillion, the sustained motorway leg — because that is where the restriction curve is steepest and where a partially filled paper panel is furthest from where it began. The claim is deliberately modest: the V7 Stone is exactly as strong as Mandello made it, and stays that way for longer than it otherwise would.

Care and cleaning

Take a compressor to the clean face and blow outwards, so the loading exits through the surface that collected it. Should air prove insufficient, wash in tepid water with a mild detergent and rinse until the water runs without colour. Everything then depends on drying it properly: room air, no heat, no flame, no impatience, because a distorted weave will pass every visual check and still be wrong. The PM138S is fitted dry and stays untreated. Sprint Filter's instructions are under Downloads.

Fitment & Compatibility

For the Moto Guzzi V7 Stone of 2021 to 2026. This panel is shared by twenty-one machines, the older 744 cc V7s among them; the Fitment tab lists every model with its build years.