HIFLOFILTRO - Foam Air Filter (OUTER ELEMENT) HFF4028 Yamaha ATV

The Hiflofiltro HFF4028 is a dual-stage racing foam air filter designed as the outer element for a range of Yamaha Bruin, Grizzly and Kodiak ATVs. It uses a dual-layer foam media formulated to trap dust and grit while keeping air flow high, so the engine breathes properly in the dusty, muddy conditions quads actually work in.

It suits farm, station and trail riders who want an OE-style replacement without any carburettor or fuelling changes. Because the foam can be washed, dried and re-oiled, one filter can be serviced and reused many times rather than replaced.

Note: this listing is for the outer element only. Machines fitted with a separate inner element will need that part sourced separately.

• Dual-stage (dual-layer) racing foam media for filtration with strong air flow
• Outer element only — sold as a single filter
• Washable and reusable; can be cleaned, dried and re-oiled repeatedly
• OE replacement fitment — no rejetting or fuelling changes required
• Suits Yamaha Bruin 350, Grizzly 350, Grizzly 450 and Kodiak 400 ATVs
• Hiflofiltro part number HFF4028

• 1 x Hiflofiltro HFF4028 foam air filter (outer element)

Confirm fitment for your exact model, year and variant before installing — use the Hiflofiltro online catalogue (https://www.hiflofiltro.com/catalogue) or your Yamaha parts listing.
This is the outer element only; if your machine also uses an inner element, inspect and service that at the same time.
Foam filters must be oiled before use — apply a dedicated foam air filter oil and work it evenly through the foam, then squeeze out the excess so the filter is damp, not dripping.
Clean with a purpose-made foam filter cleaner or warm soapy water; squeeze gently rather than wringing or twisting, which can tear the foam.
Do not clean with petrol, kerosene or harsh solvents, and do not use a pressure washer or compressed air on the foam.
Allow the filter to dry completely before re-oiling and refitting — refitting a damp filter can draw moisture into the intake.
Check the sealing face and airbox for dirt bypass on refitting, and make sure the element seats fully with no gaps.
Service more frequently in dusty, sandy or muddy riding, and inspect after any deep water crossing; follow the cleaning intervals in your Yamaha owner's manual.
Replace the element if the foam is torn, hardened, permanently discoloured or no longer springs back after squeezing.
Store spares flat or loosely in a cool, dry place out of direct sunlight, away from fuel and solvents.