Iridium Sparks plugs

Originally Posted by northwind

NGK CR8EIX, from memory.

Correct. Also www.sparkplugs.co.uk is where I got mine from and were about 15 pounds for the pair.

For the record both plugs are correctly gapped, rendering my post, pointless. Doh

Got NGK CR9EIX 3521 in mine

H

[IanG]

Just curious that according to www.sparkplugs.co.uk a K3 pointy uses the same plugs as a curvy
Just curious as to why the K4 & K5 would be different

The official Honda price for the iridium plugs for my 'Blade is £22 EACH !!! That's £88 for plugs before anything else on the service is done

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[embee]

I use http://www.spark-plugs.co.uk/ too, always deliver on time (usually next morning, how do they do that? )

Another place where I've been able to get an odd grade not listed by sparkplugs is
http://www.motocrossworld.com/site/index.php

Having said that, a friend wanted some iridium plugs for his MX-5 which weren't listed by spark-plugs, and he phoned and they were very helpful and got them for him (apparently some odd spec , don't know details).

[northwind]

Originally Posted by IanG

Just curious that according to www.sparkplugs.co.uk a K3 pointy uses the same plugs as a curvy
Just curious as to why the K4 & K5 would be different

CR8E and 9E are compatible plugs, just built for a slightly different range of conditions. From memory, 9E is recommended for a hotter-running engine?

In NGK terms, the higher the number, the colder running the plug is.

In (VERY) simple terms, the more power your engine develops, the more heat it generates in the process....and the more heat the spark plug needs to dissipate. That means a colder running plug.

All things being equal, ie the right grade selected, all plugs in all engines run in pretty much the same operating temperature envelope.

It is always safe to put a colder running plug than recommended in an engine - the only risk is that it will foul. It is never safe to put a hotter running plug than recommended in an engine - the big risk is it will overheat and cause pre-ignition.

That's a BIG adavantage of precious metal plugs - they run very cool but the electrode material makes them less sensitive to cold-fouling products.

Originally Posted by northwind

CR8E and 9E are compatible plugs, just built for a slightly different range of conditions. From memory, 9E is recommended for a hotter-running engine?

Yes the CR9s run cooler, I've got them in my curvy as I've got the ignition key advance fitted.


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Plugs sure are expensive across the pond. Here in the states they cost about 10 pounds at the most. (rough exchange estimate) ($5 USD)

Wonder why they cost so much more there........They are all made in japan.

[jambo]

Originally Posted by Torn-Thorax

Plugs sure are expensive across the pond. Wonder why they cost so much more there........They are all made in japan.

Tax and the various ways it's enforced are a constant source of ammusement. It's cheaper to buy a parallel import Triumph (built in the UK) than a genuine one apparently (It certainly was at one point a few years ago). So if you box the bike up, ship it to France, sign for it and send it back with some shuffling of paperwork it's cheaper than picking it up yourself from the factory