Iridium spark plug renewal

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jchesshyre
Posts: 590
Joined: Wed Jun 15, 2016 9:09 am
Location: Chester, Cheshire

Iridium spark plug renewal

Post by jchesshyre »

I've read some of the discussions on here about when to change spark plugs but can't seem to settle on a definite answer...probably because there isn't one.

I know Honda specified to inspect every 8000 and replace every 16000 for the platinum plugs, and in my Haynes manual it covers fuel-injected Varaderos which were fitted with iridium plugs as standard and for those an inspection interval of 16000 and replacement of 32000 is specified. However, when I've changed my iridium ones after 8000 miles I've definitely noticed a not-subtle difference in throttle response, so what the hell were they thinking with those intervals? NGK as well on their website say 'NGK gives them a life expectancy of 40-50k miles. But they have to temper their projections as driving conditions and motor modifications differ. Typically we have found you can expect 60,000 to 80,000 miles on an unaltered motor.' To be fair they're probably talking about cars, but even so...WTF?
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Wicky
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Re: Iridium spark plug renewal

Post by Wicky »

If in doubt replace... they're only a few quid.
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fabiostar
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Re: Iridium spark plug renewal

Post by fabiostar »

every 10 k i change them. for the sake of a few pounds or so..
the older i get,the faster i was :lol:
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E.Marquez
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Re: Iridium spark plug renewal

Post by E.Marquez »

I think you'll find most blokes change them well before "needed" and why not, if your in there anyway, change them out if its been awhile...
Unless they are REALLLLLLLLY old and worn or you have a runabiity issue that has them damaged or otherwise unserviced you likely will not notice a performance improvement... but if the electrode was worn, if they were coated or fouled with contaminates from crappy gas, rich mixture, oil burning.. Id bet a replacement will notice a faster start up... more then most anything else.
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jchesshyre
Posts: 590
Joined: Wed Jun 15, 2016 9:09 am
Location: Chester, Cheshire

Re: Iridium spark plug renewal

Post by jchesshyre »

When I've changed them after 16,000 miles and they look used (obviously) but generally OK I've noticed a better throttle response that's definitely not just placebo, both on this bike and my CB500.

Although people say they're cheap so why not replace them often, I don't think £15 to £20 for a pair is that cheap - it's not like they're £3 a pair or something! So while I don't want to waste money I also don't think the 32,000-mile replacement interval specified by Honda for iridium plugs seems like a good idea either. If you could clean and re-gap them I might think differently...
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