Iridium Plugs - Ducks nuts or Utter rubbish

[DR]

Loz I've run plenty of trick plugs and tried many alternatives during my life and not once did I ever feel the bike went any better because of the spark plug type I'd fitted. Regardless of what a dyno says if I can't feel a difference in the seat of my pants when riding the bike then there is no difference and no advantage and yup, I will keep using my $5 plugs because they never fail me in new bikes and cars the bling plugs maybe fine and dandy or for road racing but for old 2 stroke dirtbikes ridden below 10/10ths they're a woftam.

[mx250]

.5 here .5 there, another .5 there......... it all adds up

But the discussion here is do they continue to work or do they foul ease. Not much point in picking up .5hp for 10 minutes and loss 10% for the rest of the day. And that was my experience. My experience was with a WR250F, they foul easily and don't clean well - they need replacing, ex'y .

Careful jetting and tuning got around most fouling on the WR but still had probs when the motor got hot.

For VMX I've used B8EV's with great success with CDI bikes. With maggy's I use B8ES with great success.

[Lozza]

When you climb the greasy pole of engine tune you'll quickly find that a plug can make a real difference. As I said Doc I've converted bigger "keep it all standard' skeptic's than your good self only after a 10 min ride.Unless you have had lead fouled and porcelin exploding ES plugs your not anywhere near what the jetting can be, only then do you start to appreciate what the fine wire plugs are for. Which begs the question if there a WOFTAM why do they bother making them?

[VMX247]

Ducks nutz,more bling or mum & dad are suckers ... $$$$$   
CRF250f got one cause 15 year old is doing work place learning at MC Engineering and all the  bling kids bikes have em...
Interclub and Manjimup 50000 coming up,so will let you know the out come....I mean they gotta get ya the holshot don't they     
cheers

[lukeb1961]

I use DENSO now that last forever Doc not those NGK shitters that come fautly out of the box.

I absolutely agree with that! I had a box of NGK iridiums and had repeated problems with them. All the one box. All a headache. Some experts refuse to believe me - but that is what I experienced and clearly you did too! Ditched them and will happily use anything else 

[magoo]

The only time i've fouled a B9EV is due to bad jetting and the many times I've had my arse kicked in a race was more due to my riding ability (or lack thereof) than a spark plug. Why do people buy Iridium plugs? Dunno. Why do people buy bottled water? Same answer.

[LWC82PE]

Luke wasnt it a box of EGV's (gold palladium racing plugs) that you had issues with and not NGK's?

Why do people buy Iridium plugs?

less voltage required
increase in power and acceleration
better burning
easier starting
Long service life and even better ignitability due to a small diameter centre electrode

and from the NGK site

In recent years NGK developed a range of precious metal spark plugs that provide two major benefits over conventional spark plugs:

High Ignitability - is only achieved by utilising an exposed fine tip centre electrode allowing for superior flame growth.
Long Service Life - is achieved by utilising a high percentage of precious metals patented by NGK.
As emission laws become more stringent, the performance expectations of spark plugs also increase. NGK have developed a range of Iridium and Platinum spark plugs to meet and surpass the modern requirements of vehicle manufacturers.

Precious metals such as Iridium and Platinum have much higher melting points over traditional metals such as Nickel.

Iridium – 2410°C
Platinum – 1772°C
Nickel – 1453°C This allows centre electrode diameters to reduce from 2.5mm using Nickel, to 0.6mm using Iridium or Platinum. The finer point means that once a spark forms, the flame kernel does not have a large mass of centre electrode that reduces absorption of heat and the flame shadow impeding the flame progress. This equates to a more complete burn that translates to:

Improved acceleration
Improved fuel consumption
Smoother idling

[Lozza]

Except these aint water. I know 2 people who have dynoed about every plug on the market and was shown the same thing, 1 type of plug made approx 2-4% difference in measured HP/Torque at the wheel across the entire rev range. Didn't matter what engine effect was the same, more HP, lower CHT and EGT.Dyno's don't lie or have favourite's, they just display the numbers.
Correct Leith the NGK site pretty much spells it out to. The DENSO site calls it 'Flying Fire Voltage' (whatever that means) and basicaly adds up to less individual misfires.

[KTM495]

I have Denso iridium plugs and will never ever change back to an other plug. Bike fires up at the first kick and never fails, as long it is a Denso. I ride this plug since more then a year. Denso has a patent on them, NGK can not copy the plugs, and therefore Denso are superior.

[holeshot buddy]

lozza what sort of bike did the dyno figures come from
and iridium may be good in a car
but its not a two stroke
i have been working on (2 strokes)
for a long time now
and every time there has been an iridium plug involved
its been faulty 
so if you want to run them go for it

[Lozza]

I've done a back to back on a RS 125 Honda, the graph is of a YZ 85, I know a fellow in the UK did the back to back test on a 50cc moped racer(showed a full 1 HP gain 19-20HP) and my Kiwi guru used a 125 ICC Kart engine. Each time result was the same. Only difference my test was a 'blind' test I reached into a box of well used plugs and got the 0.5HP gain. A brand new plug I feel would have showed a 1 HP gain.
Well HB do the test and your quite welcome to try one of mine if you don't believe me or the dyno.I didn't believe it either, until I ran one.

[LWC82PE]

what are they $15 or so, pay that much and get a .5-1HP increase is pretty good value i think

[Lozza]

No that's from the Iridium racing plug, I get them from Japan ($40-50 depending on exchange rate)but for a laugh you can ask your local NGK supplier how much a R7282 -10 is.

[mainline]

on a tangent (given that it's a very basic question compared to the info in this thread) is a B8ES plug suitable to run in both a PE175 and a 79 yz125?

[LWC82PE]

for a PE you at least want a B8 EGV  (or another heat range other than 8  ) which is the original specified race plug for them. EGV is a gold paladium fine wire electode plug. Dont stick a normal 'ES'  $5 plug in a PE. These days the iridium plugs are superiour to the EGV's though. Remember the manufacturer went through a lot of testing to decide which type of plug best suits their engines and on many 2 strokes from that era it was the NGK-EGV (or equivalent type in another brand)

Lozza, was the iridum plug you use one of these (several iridium types listed here)
http://www.ngk.com.au/sparkplug.php#