NGK 5438 Spark Plug

Iridium IX Spark Plug Overview

NGK Iridium IX spark plug 5438 is built for snowmobile applications that call for a flat-seat plug with a 14 mm thread, 0.75-inch reach, and a 13/16-inch hex. It uses an iridium center electrode, nickel ground electrode, and a 0.032-inch pre-gap for direct replacement service in a wide range of Ski-Doo and Yamaha models.

Key Features

• Iridium center electrode for stable ignition performance.
• Nickel ground electrode with taper-cut tip design.
• 5000 ohm resistor for reduced electrical noise.
• Flat seat, 14 mm thread, and 0.75-inch reach.
• Pre-gapped to 0.032 inches for many listed applications.
• NGK part number 5438, also identified as BR9ECSIX.

Detailed Product Description

NGK 5438 is an Iridium IX spark plug engineered for snowmobile engines that require a flat-seat plug with the listed thread, reach, and heat range. The iridium center electrode and copper core help support consistent spark delivery, while the slant ground configuration and taper-cut tip are used to promote efficient flame initiation. This plug is listed for many Ski-Doo MX Z, Renegade, Summit, GSX, GTX, and Expedition models, as well as Yamaha SRX, VX VMAX, and Venture applications. If you are replacing worn plugs in a Ski-Doo MX Z or Yamaha VMAX application, NGK 5438 provides a direct service part reference for the specified fitments.

What It Is Used For

• Restoring ignition performance when the original plug is worn or fouled.
• Addressing hard starting caused by degraded spark output.
• Correcting misfire or uneven combustion from an incorrect heat range or gap.
• Replacing a plug with the specified flat-seat, 14 mm configuration.
• Maintaining proper operation in listed Ski-Doo and Yamaha snowmobile engines.

Installation Notes and Tips

Verify the application against the fitment list before installation. Check and set the gap to the vehicle-specific note shown in the fitment data; most listed applications call for 0.032 inches, while some Yamaha entries specify 0.028 inches and one Ski-Doo application specifies 0.020 inches. Use the correct torque procedure for the engine and confirm the plug seat type, thread diameter, and reach match the original specification. NGK 5438 may also be referenced as BR9ECSIX in catalog data.

Quality Assurance

NGK is a major OE spark plug supplier in North America and has more than 80 years of automotive manufacturing experience. The brand states that it maintains original equipment standards and uses state-of-the-art manufacturing and distribution facilities to support product consistency. Part number 5438 is backed by NGK's OE-focused engineering approach.