The UNI NU-4137ST is a high-performance, dual-stage foam air filter designed to provide superior filtration and increased airflow for the Honda CRF230F. Unlike single-layer filters, UNI’s dual-stage system utilizes two distinct layers of foam: an outer coarse-pore layer to stop large dirt and mud, and a fine-pore inner layer to trap microscopic dust particles. This design ensures maximum engine protection in harsh off-road environments while maintaining consistent power delivery through improved oxygen intake.
Dual-Stage Filtration: Two layers of specialized foam work together to provide maximum protection against silt, dust, and sand.
Increased Airflow: High-flow foam technology allows the engine to breathe more efficiently than standard paper or dense OEM foam filters.
Seamless Construction: Features UNI's "Ultra Seal" grease groove on the sealing surface to ensure a leak-proof fit against the airbox.
Washable and Reusable: Designed to be cleaned and re-oiled repeatedly, providing a significantly longer service life than disposable filters.
Chemical Resistant: Constructed with high-strength adhesives and foam that resist breakdown from gasoline and aggressive air filter cleaners.
Filter Cage: This filter is designed to slide directly over your OEM plastic Suzuki filter cage. Do not discard your factory cage.
Oiling the Two Stages: Because the two foam layers separate, oiling and cleaning is a breeze. Pull the red outer foam off the yellow inner core. Oil both layers generously with a quality foam filter oil, massage it deeply into the foam cells, and firmly squeeze out the excess. Never twist or wring the foam like a wet towel, as this will shear the cells and ruin the filter. Let the carrier solvent in the oil flash off in a well-ventilated area for 15 minutes before reassembling and installing.
Part Number: NU-4137ST
If you have any questions or need help finding what you need for your motorcycle or your next adventure please reach out:
EMAIL US AT tmbrmoto@tmbrmoto.com- OR CALL - 208-254-2044
