Function of the Spark Plug

The spark plug is a key component of the engine: it generates the spark that ignites the air-fuel mixture inside the cylinder. A precise and consistent spark ensures quick starts, smooth operation and optimized fuel consumption.

NGK Spark Plug Types and Features

A) Standard (copper) spark plugs

• The most common and affordable solution.

• Excellent thermal conductivity, ideal as an OEM replacement for everyday scooters and motorcycles.

• Require more frequent replacement compared to precious metal versions.

B) Platinum spark plugs

• Longer life thanks to the platinum electrode.

• Maintain the correct gap for longer, ensuring consistent ignition.

• Great for those seeking a balance between performance and longevity.

C) Iridium spark plugs

• Ultra-thin iridium central electrode for a more precise spark.

• Maximum durability and improved throttle response.

• Perfect for sports bikes or riders who want top performance and reduced maintenance.

Heat Range: what it means

The number in the NGK code indicates the plug’s heat range.

• Lower numbers = hotter plug (retains heat).

• Higher numbers = colder plug (dissipates heat faster).
  Choosing the right heat range is crucial: a plug that’s too hot can cause overheating, while one that’s too cold may lead to fouling.

Resistance, gap and multi-electrodes

• The letter “R” in the code identifies resistor spark plugs, which reduce interference with the vehicle’s electronics.

• The gap (distance between the center and ground electrode) is factory-set but should always be checked according to the motorcycle or scooter specifications.

• Some models use multiple ground electrodes for greater durability and reliability.

How to read the NGK code

The printed code on the plug contains essential information:

• Initial letters = thread diameter/type.

• Central number = heat range.

• Final letters/numbers = details such as resistance, thread length and construction type.

Practical tips

• Always follow the vehicle manufacturer’s recommendations for code and specifications.

• Check the gap before installation.

• Replace plugs regularly to keep the engine efficient.

• Highlight the benefits: affordability (copper), balanced performance (platinum), top efficiency and reliability (iridium).