NGK Spark Plug Stock # 3722

The NGK Spark Plug Stock #3722 (BR5HS) is a standard-heat-range spark plug engineered for small-displacement gasoline engines found in motorcycles, ATVs, generators, lawn equipment, and marine applications. This resistor-type plug delivers reliable cold-start ignition and steady combustion performance across a wide range of operating conditions, making it a trusted OEM-equivalent replacement for both routine maintenance and field repairs.

Built with a 14mm thread diameter and 0.500-inch reach, this NGK plug mounts flush with a gasket seat for proper compression and sealing. The resistor core suppresses radio frequency interference (RFI) that can disrupt electronic ignition systems and fuel management circuits—a critical feature in modern small-engine equipment where EMI suppression directly affects fuel economy and emission control performance. NGK's manufacturing tolerances and electrode gap precision ensure consistent spark timing and reduced misfires compared to generic alternatives. The compact 3.45-inch overall length and 0.12-pound weight make installation straightforward in confined engine bays.

This spark plug suits anyone maintaining small-displacement recreational or utility engines—dirt bike riders replacing plugs between riding seasons, ATV owners prepping for hunting trips, generator operators restocking spare parts, or marine technicians stocking replacement inventory for outboard engines. Its standard heat range handles moderate to high-RPM operation without fouling or overheating, covering the performance envelope of typical single-cylinder and small twin-cylinder engines.

NGK spark plugs are recognized across the small-engine and powersports industry for consistent electrode wear rates and long service intervals. BR5HS plugs represent the standard choice for OEM replacement, maintaining the original equipment's thermal and electrical characteristics without modification or tuning adjustments.