K&N Universal Custom Air Filter - Oval - Red - 51mm Neck Flange

Oval High-Flow Washable Carburetor Air Filter with 51mm Neck Flange

The K&N 56-9105 is a universal oval high-flow washable air filter designed for single or two-barrel carburetors with a 51mm neck flange. The K&N 56-9105 uses K&N's multi-layer cotton gauze filtration media oiled and pre-charged from the factory for maximum airflow with effective filtration right out of the box. The 56-9105 is part of K&N's custom air filter series for carburetor applications, providing a high-flow replacement for stock carburetor air filter elements in performance builds, classic restomods, hot rods, and any application using a 51mm flange carburetor top. The K&N 56-9105 is washable and reusable, with a 1-Year Limited Warranty.

K&N Cotton Gauze Filtration on the 56-9105

The K&N 56-9105 uses the same multi-layer oiled cotton gauze media K&N has engineered since 1969. Cotton gauze filters more particulates per square inch of filter area than standard dry paper elements while flowing significantly more air, which is the fundamental reason K&N filters deliver performance gains in high-flow carburetor applications. The 56-9105 oval shape maximizes filter surface area within the available height, giving the carburetor a larger total filtering surface compared to a round filter of the same height. When the 56-9105 gets dirty, it is cleaned with K&N Refresher Kit rather than replaced, making it a lifetime filter with proper maintenance.

What's Included

• 1 x K&N 56-9105 oval washable air filter, pre-oiled, with 51mm neck flange

Specifications

Frequently Asked Questions

What carburetors does the K&N 56-9105 fit?
The K&N 56-9105 fits any single or two-barrel carburetor application with a 51mm (approximately 2-inch) inside diameter neck flange. This includes many Weber, Holley, Rochester, Carter, and Solex carburetor tops as well as various aftermarket carburetor hat adapters with a 51mm opening. Measure your carburetor flange ID before ordering to confirm fitment.

Does the K&N 56-9105 come pre-oiled?
Yes. The K&N 56-9105 ships from the factory pre-oiled and ready to install. No additional oil is required before first use.

How do I clean the K&N 56-9105?
Use K&N Refresher Kit (K&N 99-5000 or equivalent). Apply K&N Power Kleen cleaner, let soak, rinse with water, allow to fully dry, then apply K&N Air Filter Oil to the filter media. Never use compressed air to dry or clean a K&N cotton gauze filter. Over-oiling the 56-9105 can affect MAF sensor readings if used in MAF-equipped fuel injection applications.

Is the K&N 56-9105 street legal in California?
The K&N 56-9105 is a universal carburetor air filter. It is not a California Air Resources Board (CARB) certified replacement filter for a specific late-model EFI application. Its legality for street use depends on the specific vehicle, state emissions regulations, and whether the vehicle is subject to emissions inspection. Check your local emissions requirements.

Can the K&N 56-9105 be used on a fuel-injected engine with a throttle body?
The K&N 56-9105 is designed for carburetor applications with a 51mm flange. It can be adapted to a throttle body inlet if the flange dimensions match, but K&N offers dedicated throttle body and intake filter products that may be better suited to fuel-injected applications. Confirm your flange diameter before ordering.

Does the K&N 56-9105 increase horsepower?
The K&N 56-9105 flows more air than a standard paper element filter of comparable size due to the oiled cotton gauze media design. In carburetor applications where the factory filter is a restriction, replacing it with the 56-9105 can improve throttle response and top-end breathing. Actual gains vary by application, carburetor jetting, and overall intake configuration.

What is the neck flange length on the K&N 56-9105?
The 56-9105 uses a standard K&N custom filter flange length. For exact flange length dimension, consult the K&N filter dimension chart at knfilters.com using the 56-9105 part number to confirm fit with your carburetor top before installation.

Is the K&N 56-9105 covered by a warranty?
Yes. The K&N 56-9105 is covered by K&N's 1-Year Limited Warranty against defects in materials and workmanship.

Install Instructions

Confirm that your carburetor neck flange ID is 51mm before installing the K&N 56-9105. Remove the existing air filter element or air cleaner assembly from the carburetor top. Slide the 56-9105 neck flange over the carburetor inlet. Secure with the existing wing nut and base plate hardware if applicable, or use K&N supplied components. The filter ships pre-oiled, no additional preparation is required before installation. Do not allow the filter to contact engine surfaces or heat sources. Check filter clearance to the hood before closing.