Spark Plug Colour

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I had a chance to compare the plug colour of the old OEM NGK plugs and the Denso Iridium plugs I put in 6000 miles ago.

The OEM ones were a nice tan colour, which is to be expected, I think.

The iridium plugs were distinctly paler, with one side pretty much white, indicating (i think) a leaner, hotter burn.

Is this what others see? Is this something to be worried about? Are plug colour threads akin to 'what oil' threads? Does Hitler have an opinion on this ???
 
i think the colour will be more affected by how it's been recently ridden than the plug itself if they are of comparable heat range.

on a modern bike, i think any deposit (white, grey, tan) that isn't black will be fine.

metallic or no deposit at all/shiny insulator = bad news.
 
It may be that the temperature range on the Denso Iridium is slightly wrong so the plugs are running a bit hot. Which plug are you using? I have the IXU24 fitted, but have not removed them yet to see how they are running.
 
It may be that the temperature range on the Denso Iridium is slightly wrong so the plugs are running a bit hot. Which plug are you using? I have the IXU24 fitted, but have not removed them yet to see how they are running.

That would be my suggestion, the plugs are running hotter.
 


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