K&N 04-05 Honda TRX450R Air Filter - HA-4504

The K&N HA-4504 replacement air filter is a high-flow, washable air filter designed specifically for the 2004-2005 Honda TRX450R. Built for off-road riding conditions, this drop-in filter is engineered to deliver increased airflow over a standard paper element, helping your TRX450R breathe better on the trail. If you're looking for a Honda TRX450R air filter upgrade that installs like a factory unit but performs well beyond stock, the K&N HA-4504 is one of the most recognized options in the aftermarket.

Key Features & Benefits

• High-Flow Design for Increased Performance: K&N's signature high-flow filtration is designed to provide increased horsepower and acceleration compared to standard disposable paper filters — a genuine benefit for riders pushing their TRX450R hard.
• Washable & Reusable: Unlike conventional paper air filters that get thrown away, the HA-4504 is washable and reusable. Clean it with K&N's cleaning kit, re-oil, and reinstall — saving money over multiple seasons of riding.
• Off-Road Specific Construction: This filter is specifically developed for off-road ATV use, meaning its filtration media and sealing are intended to handle the dust, dirt, and debris conditions that TRX450R riders encounter on trails and motocross tracks.
• Drop-In Replacement Fit: The HA-4504 is a direct replacement for the OEM air filter on the 2004-2005 TRX450R. No modifications, adapter kits, or cutting required — it slots into the stock airbox like the factory filter.
• Lifetime Filter — Long-Term Value: K&N markets the HA-4504 as a lifetime engine air filter, meaning with proper maintenance it is designed to outlast the vehicle's service life, eliminating the recurring cost of disposable replacements.

Specifications

• Brand: K&N Engineering
• Part Number (MPN): HA-4504
• SKU: KNNHA-4504
• UPC: 024844105165
• Filter Type: Drop-In Replacement Air Filter
• Application: Off-Road ATV
• Proposition 65: Yes — California Prop 65 notice applies

Fitment

The K&N HA-4504 is confirmed to fit the following vehicle:

• 2004 Honda TRX450R
• 2005 Honda TRX450R

This filter is a drop-in replacement specifically designed for the TRX450R's stock airbox for these model years. If you ride a TRX450R from a different model year, or a different TRX model such as the TRX400 or TRX500, verify compatibility before ordering — the HA-4504 is not confirmed to fit those applications. Not sure if this fits your specific build? Contact ThreePiece.us fitment support before purchasing.

Why Buy from ThreePiece.us

• Free Shipping on Every Order: The K&N HA-4504 ships free to your door — no minimum order, no handling fees.
• Affirm Financing Available: Break your purchase into manageable payments through Affirm, so you can get the parts you need now without waiting.
• Expert Fitment Support: ThreePiece.us has served 10,000+ customers and has a knowledgeable team available to verify parts fitment before you buy. Call 813-535-5801 or email sales@threepiece.us with your VIN or riding setup details.
• In-Stock & Ready to Ship: The HA-4504 is regularly stocked, so you won't be waiting weeks for a backordered part before your next ride.
• Price Match Guarantee: ThreePiece.us offers a price match guarantee — if you find a lower price elsewhere, reach out to the team.

Frequently Asked Questions

Q: What years and models does the K&N HA-4504 fit?
A: The HA-4504 is confirmed to fit the 2004 and 2005 Honda TRX450R. It is a direct drop-in replacement for the stock airbox on those specific model years. If you have a different year or a different TRX model, contact us to confirm compatibility.

Q: Is this a washable, reusable filter or a disposable one?
A: The K&N HA-4504 is a washable and reusable high-flow air filter. K&N describes it as a lifetime filter — with regular cleaning and re-oiling using a K&N Recharger kit, it is designed to last indefinitely rather than being discarded after each service interval.

Q: Does this filter require any modification to install on my TRX450R?
A: No. The HA-4504 is a drop-in replacement designed to fit directly into the OEM airbox of the 2004-2005 Honda TRX450R without cutting, adapters, or custom fabrication.

Q: Does this product carry a California Proposition 65 warning?
A: Yes. The K&N HA-4504 is listed with a Proposition 65 notice. California residents should be aware of this before purchasing.