NGK MAR9A-J Spark Plug – 6869

The NGK MAR9A-J is a specialized, high-performance spark plug engineered specifically for high-revving, high-compression engines. Unlike standard plugs, it features a dual-ground (multi-ground) electrode design. This configuration improves ignition reliability and ensures a consistent spark even as the electrodes wear over time, extending the service life in demanding conditions. Built with a 98% pure copper core for superior heat dissipation and a trivalent metal plating to prevent seizing, the MAR9A-J is the go-to OEM replacement for riders who refuse to compromise on their machine's ignition timing and power delivery.

Features:

• OEM-recommended NGK copper-core spark plug

• Provides consistent, reliable ignition for high compression engines

• Stable performance in both low-speed and high-load riding

• Resists fouling in technical terrain at lower speeds

• Factory-set 0.8 mm spark gap  **See Tech Note Below

• Heat range: 9

• Built to NGK’s industry-leading quality standards

This plug is a "Solid Terminal" type, meaning the top nut does not unscrew. This is standard for the specialized ignition coils used on Ducati and modern European platforms. Always check your service manual for the specific torque spec, typically 7.2–8.7 lb-ft for aluminum cylinder heads.

Do Not Attempt to Gap This Plug

Unlike standard single-electrode plugs where you can bend the ground strap to adjust the clearance, multi-ground plugs like the MAR9A-J arenot adjustable.

• Fixed Geometry: The dual ground electrodes are positioned to provide a specific spark path. Attempting to "gap" them with a traditional tool can easily tweak the electrodes off-center or crack the insulator nose.

• Out of the Box: If the gap is not within the 0.7mm – 0.8mm range due to shipping damage or a dropped plug, NGK recommends replacing the plug rather than trying to bend the electrodes back into spec.

TMBR Tech Tip: On the high-compression Ducati engines this plug typically serves, even a tiny fracture in the ceramic caused by manual gapping can lead to a catastrophic engine failure if the tip drops into the combustion chamber. Check it with a wire gauge, but don't touch it.

Part Number: 6869