K&N HA-4099 High-Flow Air Filter for 1999-2014 Honda TRX400EX/TRX400X

Vehicle Fitment

• 1999-2008 Honda TRX400EX / Sportrax 400 (400 cc 4-Stroke)
• 2009, 2012-2014 Honda TRX400X (400 cc 4-Stroke)

Fitment Notes

• Only compatible with models listed above; not for other ATV/UTV platforms or years.

Features

• Pleated cotton-gauze media for high air flow and excellent filtration
• Washable, reusable & pre-oiled - ready to install out of the box
• Large filtration surface area for long service intervals
• Direct OEM airbox fitment with application-specific sealing bead
• No fuel-management modifications required
• Improved throttle response, acceleration, and engine breathing
• Ideal for dusty or off-road conditions - optimized for ATV/off-road use
• Durable construction for long-term use and repeated cleanings

Specifications

• Filter Height: 4.50 in (114 mm)
• Large-End Outside Diameter: 5.375 in (137 mm)
• Base Outside Diameter: 5.125 in (130 mm)
• Flange Inside Diameter: 3.00 in (76 mm)
• Shape: Round Tapered
• Material: Multi-layer cotton gauze between aluminum mesh
• Weight: ~1.25-1.40 lb (≈ 0.56-0.64 kg)
• Position: Drop-in air filter element (OEM airbox)

Included Components

• 1x High-flow air filter (HA-4099)

Product Description

The K&N HA-4099 High-Flow Air Filter is a direct OEM-replacement air filter engineered specifically for Honda TRX400EX (1999-2008) and TRX400X (2009, 2012-2014) ATVs. Designed for off-road and powersports use, the filter uses pleated cotton-gauze media sandwiched between aluminum mesh for superior airflow and filtration compared to standard paper filters.

Because it's washable and reusable, HA-4099 offers long-term value and reduces replacement waste. Installation is simple - remove the stock air filter and drop in the HA-4099; the dedicated sealing bead ensures a secure and precise fit. Riders benefit from improved throttle response, smoother engine breathing, and consistent performance even under dusty or demanding off-road conditions, without needing fuel-system modifications.

Ideal for ATV enthusiasts, trail riders, or anyone seeking to maximize engine performance and longevity on their Honda TRX400EX / TRX400X. The HA-4099 is a reliable, maintenance-friendly upgrade that balances airflow, filtration, and durability for off-road adventures.