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Discussion Starter · #1 ·
Most of the spark plug threads here are for big bores or setups where the stock heat range is too hot. NGK also has an iridium in the stock heat range that does not tend to cross-reference with the stock plug, CR6EIA-9. I went with heat range 6 because most of my riding is commuting: low engine load, short run times, moderate weather. Here is an NGK decoder that shows exactly what each character means.

Text Line Font Parallel

Others tend to run colder plugs for higher output, higher load applications.

Here's a side-by-side of the stock Denso and the iridium NGK

Spark plug Auto part Fastener Metal Screw Spark plug Auto part Automotive ignition part Automotive engine part Pipe Spark plug Auto part Automotive engine part Automotive ignition part Suspension part
One other note, this will not perform differently than any other suitable spark plug in any perceptible way; Claims of crisper response, stronger top end, or other benefits come from either replacing a severely worn plug with a new one, or, the placebo effect.

A good reference for what the heat range really means and why you want to get it right for your application is found here:
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