– Chrome backing plate – For use with the OEM oval 2-bolt air cleaner cover – Stage 1 red pre-oiled filter element. The best and simplest performance air cleaner kit for your bike… period. Gain up to 21% horsepower by simply installing a Big Sucker™ kit on your intake. Backing plates: The Big Sucker aluminum backing plates feature a radiused inlet to optimize airflow for both carburetor and fuel injection applications. The built-in breathing system features hidden channels to prevent the use of unsightly exposed breather hoses and fittings. Note: See 958900 for the replacement filter element only.