Irridium spark plugs from NGK Racing Series 

Explanation of NGK heat numbers and how to use them on a go-kart engine

In damp cold weather you need NGK 8

Normal weather like12-23 degrees NGK 9

Warm weather around 23 degrees and more NGK 10

For engines such as J125, S125, IAME, Rotax, J60, TM, Vortex, X30 etc..

• Thread: 14x1,25 mm
• Wrench: 21 mm
• Resistor: yes