Bel-Ray Foam Air Filter Oil Spray 400ml — Waterproof, High-Viscosity Protection for Foam Filters

Bel-Ray Foam Filter Oil Waterproof Spray 400ML is a high-viscosity, spray-on filter oil designed to form a water-resistant, particle-trapping barrier for foam air filters used on street, off-road, and race machines.

This spray delivers a thick, tacky coating that improves the ability of foam filters to catch dust and fine particulates while resisting washout when exposed to water or mud. The aerosol format makes application fast and even, reducing mess and ensuring the oil reaches inner foam layers without saturating the surrounding parts. Lightweight packaging is easy to store in a garage or pit box.

How does this spray protect foam air filters during wet conditions?

The waterproof formulation is engineered to stay in place when the filter gets wet, preventing the oily barrier from liquefying and running off. That helps keep the filter’s porous structure effective at trapping contaminants even after exposure to rain, puddles, or mud. It does not replace regular cleaning but extends filter performance between services.

• Water-repellent chemistry helps prevent oil washout in wet environments.
• Maintains tackiness to capture fine particles after exposure to moisture.
• Suitable for off-road, motocross, and dual-sport riding where water contact is common.

Will this spray affect airflow or engine performance?

Bel-Ray’s ultra-viscous oil is formulated to coat foam fibers without clogging pores, striking a balance between filtration efficiency and unrestricted airflow. Proper application — a light, even layer — preserves breathing capacity while improving particle capture. Over-application can reduce airflow, so follow recommended spray distance and drying time.

• Designed to penetrate foam for an even coating without blocking airflow.
• Aerosol format helps control coverage to avoid heavy buildup.
• Improves particulate retention while maintaining acceptable flow when applied correctly.

How do I apply and maintain the filter with this product?

Apply the spray to a clean, dry foam filter in short bursts, flipping the element to coat all sides and inner layers. Allow the oil to set and distribute evenly, then remove any excess to prevent drips into the intake. Clean and re-oil regularly depending on riding conditions and manufacturer guidance.

• Spray evenly from a short distance in light passes to avoid saturation.
• Work oil into inner foam layers by gently flexing the element after application.
• Reapply after a thorough wash-and-dry cycle or when oil appears diminished.

Who is this product for? Bel-Ray Foam Filter Oil Waterproof Spray 400ML is intended for riders, racers, and mechanics who use foam air filters on motorcycles, ATVs, UTVs, and other powersports machines and need a durable, water-resistant protective coating. It’s also useful for anyone seeking a quick, controlled application method to restore filter tackiness and particle-trapping ability without messy hand-rubbing. Not a substitute for routine filter cleaning; it's a conditioning and protection step between service intervals.

Product details:

• Net volume: 400 milliliters (aerosol spray).
• Item package dimensions: 7.90L x 2.51W x 2.47H inches; package weight 0.85 pounds.
• Pack quantity: 1 can; formulated for foam-type engine air filters used on street, off-road, and racing applications.