Iridium spark plugs?

[Foamer]

I have iridium plugs in at the mo, been in for 25k or so, do they really last for 100k ? Do you think I would notice a difference if I replaced them ? , bike never misses a beat and runs perfect.
K1

[Cymraeg_Atodeg]

I had them in mine over the standard two prong set that were in Leana when I bought her, as to a difference, not really. She pulls like a train with or without the "iridium" plugs

[TazDaz]

I am still on original plugs after 13k...hmmm.

[Cymraeg_Atodeg]

The best way to check spark plugs is take them out, check the gap, check the core and check the over-all condition. If the bike is still running OK why change them?

[Foamer]

Found this on a spark plug website,

'Service life of some OEM Iridium spark plugs can be as much as 120000 miles with very little degrading of performance in that lifespan. NGK Iridium IX types have a centre electrode tipped with Iridium alloy with a 0.6mm diameter. NGK believe this gives the optimum balance between performance and service life. Service life estimates can be up to 60000 miles for normally aspirated car engines and up to 20000 miles for motorcycles - this is extremely subjective though, a high revving motorcycle or extremely modified car engine will most likely wear plugs out in a few thousand miles.'

Motorcycles 20k, I may be due a change or do I keep going ?

[Cymraeg_Atodeg]

Well, to be honest it is about £11 for two spark plug, so, you really worried about the cost?

http://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/46492
£5.70 Standard

http://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/46521
£9.11 Iridium

[Foamer]

The best way to check spark plugs is take them out, check the gap, check the core and check the over-all condition. If the bike is still running OK why change them?

I agree, if its not broke ..........
Just thinking I may have got used to a gradual deterioration and less fuel economy

[Wideboy]

they're meant to help with better cold starting, i tried them saw no change so never bothered with them again and stuck to cr9e's due to my motorway miles

[Foamer]

Gonna put a new pair in next time I'm self servicing and see, I'll get the psychological improvement, always happens, clean up the old pair and keep em on the shelf

[Foamer]

Sent for 2, £15.80 the pair delivered, sparkplugs.co.uk

Thanks for the replies

[northwind]

Make no difference to performance I can tell, but I'm convinced they do improve cold starting (did some a/b testing through winter one year) and also seem more tolerant of bad mixture (which is handy if you're a bodger)

I just changed a set that are about 30000 miles old, seems to be no degrading in performance at all so they'll be going back in but I already had a new set :P

[embee]

I generally recommend the use of iridium plugs. They do offer real technical benefits, longer service life, better cold starting, better tolerance to poor mixture control, lower voltage requirement so easier life for the rest of the ignition system etc.

Whether you'll "notice" any difference is debatable, depends how sensitive you are and how well the engine is set up. I just treat them as an advance in technology which makes sense, and now they are a small oncost it seems a no-brainer. I've used http://www.spark-plugs.co.uk/ in the past and had very good service though their prices are a bit less competitive these days. I have just received some iridium plugs from an ebay supplier (Channel Islands it turns out), £16 for 3 plugs delivered, so shop around.

With small thread diameter (10mm) plugs the service life can sometimes be down to the central insulator, which is why cars tend to stick to 14mm thread plugs even now, so a 10mm plug won't have quite the service life of a 14mm plug but even so 20-30k miles should be no issue at all.

[Rocket]

I've still got the original factory plugs in my 03 thou after 68,000 miles. They did need the gap reducing at 50,000 miles due to errosion but other than take them out every 5,000 miles when I do the oil and filter to make sure they do not seize in they are staying put. I carry a spare pair of plugs under the seat just in case as they can be fitted at the roadside with the factory toolkit should I ever need too. According to the manual I should have been changing the plugs every 7,500 miles so I reckon that's a fair bit of money saved.