Spark Plugs

[Rhino]

I replaced my plugs when I did my valves at around 30k. I don't think they needed replacing but since I was in there anyway, might as well. Will probably replace again when I do the valves again around 60k this year some time.

[B.D.F.]

The center electrode makes no difference in end- gapped plugs, and iridium plugs gap like any other, common, spark plug- by bending the outer electrode. According to the Kawasaki manual:

Electrical System
Spark Plug:
Type NGK CR9EIA-9 – – –
Gap 0.8 ∼ 0.9 mm (0.031 ∼ 0.035 in.) – – –

Mine were all gapped at 0.035" at 25K miles and all w/in 0.001" of that at 50K, when I changed them.

New plugs are all have the proper gap from the factory but I check them just in case they were bumped and have found the occasional plug with a significantly smaller gap, though never with a larger gap than spec'd.

There are a few types of spark plugs that the gap cannot be set on but they are not used in normal street vehicles. The surface gap spark plug is a great example: the gap was determined by the machining diameters and fixed by the porcelain that holds them apart. Nothing short of a vice and a hammer would alter the gap and to actually do that the plug would be ruined anyway (crushed porcelain).

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Brian