NGK BR10ECM Spark Plug – Stock No. 4234
The NGK BR10ECM is a cold heat-range, resistor spark plug built for hard-running two-stroke and high-rev engines. It delivers strong ignition under load and helps reduce misfire at high RPM. The cold rating (NGK 10) manages combustion heat effectively in performance use, supporting consistent power and plug life when tuned correctly.
It uses NGK’s reliable nickel-alloy centre electrode with a gasket seat for a secure seal. The B thread family gives a common 14 mm fit, and the resistor helps control electrical noise that can interfere with modern electronics and data loggers.
Use this plug where a cold range is specified – typically in performance two-stroke motorcycles, kart engines and similar competition applications. Always confirm fitment and heat range against your engine builder’s or manufacturer’s guidance.
| Part number | BR10ECM |
|---|---|
| NGK stock number | 4234 |
| GTIN | 087295142349 |
| Category | 686 – Spark Plug |
| Thread diameter | 14 mm (NGK B) |
| Thread pitch | 1.25 mm |
| Thread reach | 19 mm (NGK E) |
| Hex size | 20.8 mm (13/16 inch) |
| Seat type | Flat seat with gasket |
| Resistor | Yes (NGK R) |
| Heat range | 10 (very cold – performance/competition) |
| Electrode material | Nickel alloy centre, ground strap |
| Factory gap | Typically around 0.6 mm – check and set to your engine spec |
- Cold heat range helps control plug temperature in high-RPM, high-load running.
- Resistor design reduces electrical noise affecting ECUs and data systems.
- Durable nickel electrodes for dependable spark and service life.
Important: This is a cold-range plug typically for performance two-stroke or competition engines. Using too cold a plug in a mild or road engine can cause fouling. Confirm fitment and heat range using the site’s vehicle lookup or see the Vehicle Fitment tab.
The price displayed is for a single plug, please add the desired amount to your basket.



