Yamaha TRX850 Enthusiasts Forum

Hi all, has anyone tried these Iridium spark plugs i keep seeing on evil bay? Do they improve things and do they last ect. sorry if this has all been talked over before.
Cheers.

I use them and was advised to due to higher running temp of tuned engine - not sure I'm convinced of the benefits (full stop) let alone on a stock motor.

The actual 'science' makes sense though

The basic science:

By making the plug's centre electrode out of Iridium, then it can be narrower, the narrower the centre electrode is, the lower the potential difference (voltage) that is required to jump the gap between centre and ground electrodes.

Also as the iridium electrode is harder, they last longer.

But as you have no control over the potential difference of the ignition, then you can't benefit from the primary advantage.

They are of questionable value in a bike/car with a standard ignition system, (even higher performance engines) unless you want plugs that last longer. Most standard plugs will last longer than the majority of owners keep their bikes anyway.

The smaller electrode also gives a thinner spark, which may not light a leaner mixture as effectively as a traditional spark, My opinion and it's only that is that most of these flash new spark plugs are a bunch of arse, iridium ones do however last a whole shedload longer than standard ones so in that regard they may be worth the extra dough, but dollars for horsepower they are a waste.

Thanks chaps as my motor is in standard tune it dont seem worth the extra cost, i'll stick with standard.

G'day all, long time member first time poster. I have installed Denso iridium "POWER" plugs in my TRX as well as VFR800 & Ducati 888. All have responded well, from idle to redline they feel "crisper" & the VFR now burbles nicely on the over-run. Note, there is a difference between Iridium plugs & Iridium "power" plugs. Money well spent I say.