Iridium Plugs - Ducks nuts or Utter rubbish

[Lozza]

When the plug swap told me the NGK shitter shat itself I immediately removed your dodgy old ES I threw that in the bin(where they belong ) and put a DENSO IW-29 in which is still in there,functioning perfectly today,on a 400 with a old high voltage AC ignition.NEVER to use NGK again.
Like I said Doc there is no free lunch,a race plug will allow/demand some changes to get the most from them.In making the changes you can expect a 2-4% increase in power across the rev range all for $40.The plug by itself won't show any difference, the CHANGES the plug ALLOWS makes difference, simple innit ::)Which I'll say again I yet to see any actual evidence of a similar priced product producing as good a gain.
Caps that's a good price for that plug the DENSO equivalent is IU01-27 which would be about $150-160 for a box of 4 out of Japan, the Denso's last forever.

[DR]

  this is vintage play racing we're talking Loz. It's not Eastern Creek, it's not modern and it not about extracting every last poofteenth of HP from a 25 or 30 year old motor. There are some who persue the ultimate but it's meant to be FUN. There is no major glory or pay cheques to be gleaned at the end of the day regardless of where you finish. For the average vintage bike and average rider a B8ES requires absolutely no changes to keep circulating happily all day or all year for that matter. Not everyone has the experience or knowhow to make the tuning changes you mention to allow these plugs to work correctly and gain that little extra HP. I sure as eggs don't An ES is a more suitable plug for Joe Average and his Joe Average vintage bike (no offence YZ as I refer to myself here )  this was the original question put forth at the beginning of the topic. An iridium plug in this particular instance will not provide any substancial gain and may well have the opposite effect in a motor not tuned/modified to suit

No worries Leith, just stirring the pot a little is all  

[YZ250H]

It's all good Doc - I'm not one to take offence - ever.  I've got a foot in both camps anyway .  I will put the B8ES in while I get the thing running properly and then change to the Denso Iridium (still aghast at how much it cost - it's all relative I suppose.  Just seemed like a lot of money to pay for "just a spark plug")
This has been a very interesting topic that I'm glad I started.  I have no leaning one way or the other, but I intend to get my pound of flesh out of that expensive bugger.  BY the sound of it they don't perform well in a poorly tuned engine, so I will put he B8ES in until I get it closer.  I'll keep track of any changes I notice and have my story ready for the next time someone asks    Wonder which camp I will be in 

[firko]

After spending just shy of $500 for the NGK iridium plugs that "I needed" for my old Jag because of its modified ignition and engine management system I gained diddly squat improvement in performance and the car actually became harder to start. Prior to changing to the iridium plugs because some Melbourne Jag racing guru told me that it'd be "absolutely nessessary" I'd been running cheapo KLG plugs that cost me about 3 bucks each at Supercheap with no dramas whatsoever. My newer Jag has the same MDS ignition and plain old Champion plugs and it starts far easier than the old car. I can't compare the two cars performance though as the engine on the newer car is bigger and runs a totally different management system.
My thoughts on iridium plugs in the above application? An expensive waste of money.

On my bikes I have two opinions. I was told by other Maico owners who used PVL ignition that it was imperative that I use Iridium plugs or the bike wouldn't start and would underperform. After some dramas I eventually found short reach Iridiums and the bike performed superbly and much better than the old points/ES combo. When I fouled a plug on the bike I didn't have a spare iridium with me so I replaced it with an EV and made no other changes. The bike became impossible to start on the kicker and had to be push started every time. I then borrowed a long reach iridium from another racer and packed it with washers to achieve the correct reach and..voila!....the old girl started first kick of the kick starter. I have PVL in my upcoming Yamaha 360 and won't even bother with the non iridium plugs on that and may even take Lozzas advice (!) and use a Denso for the first time in my life. On my other bikes with production based or Chinese pit bike ignitions, I wouldn't bother with the expense. A good old fashioned B8ES will probably do the trick as efficiently as they have for the last 30 years.

I totally agree with Doc's statement and truly believe that many of us tend to over intellctualise what we're doing with these old bikes. The bottom line is that in most cases we're merely out to have a bit of fun on our favourite old bike. We're not racing for million dollar cheques and the opportunity to bed Dannii Minogue, the poofteenth of a second per lap increase in performance means SFA to most of us. More useful gain can be made by going on a diet, training and doing a couple of riding schools. The truly fast guys in our sport more often than not run bog stock bikes and probably wouldn't know what plug they use. The riding is what it's about, not .5 of a horsepower @6000rpm. If you feel the need to have that .5 of a horsepower, go right ahead and spend $50 bucks on your spark plug. You may feel better but let me tell you...it ain't going to make a smidge of difference to your enjoyment of the sport.   

[mike1948]

I guess what is most important to me is not more power, but which plug makes my bike easier to start.  Can't go too fast if you're buggered from pushing and kickng the thing.  I use an iridium plug in my Maico which starts first kick, but my spare is a B8ES.
Mike

[Lozza]

Sure that's true Doc just when I've recovered from your extolling the virtues of a 20yr old TS 185 shocks  , truth is if you bought a iridium plug you would hoping for some sort of a gain, otherwise you would have just bought the plain old ES.Why buy new shocks,why use a forged piston, why use an electronic ignition?Why not just stick with points, original shocks and NOS pistons?If it was all about riding round and round on Sunday arvo and not about extracting more out of an engine doesn't explain why those shitter gold anodised heads consistantly set off  ebay bidding frenzies?It's easy to change a jet or retime an ignition you just have to want to be able to do that.?That costs nothing and you gain some knowledge you didn't otherwise have. I don't see anywhere I have stated that these plugs are necessary to ride around on Sunday,I fail to see how any one person can judge what makes someone else happy or what they their personal enjoyment from. Plus the question was not if the average punter will make faster lap times , nor was it a debate about what plug you should and shouldn't be running, question simply was are they 'duck guts or utter rubbish'.
In which I rest the case for the affirmative in the complete lack of anything other than heresay and irrelevent and emotive arguements for the negative

[YZ250H]

Well said Lozza, your argument has been consistent and logical all the way through.  Seems we'll never agree, so perhaps each to his own    I'll still be using mine.

[crabman]

I guess what is most important to me is not more power, but which plug makes my bike easier to start.  Can't go too fast if you're buggered from pushing and kickng the thing.  I use an iridium plug in my Maico which starts first kick, but my spare is a B8ES.

I recently bought a high performance Maico motor out of the USA. The engine builder went to great lengths to caution me about using a non iridium plug with 102 octane fuel. I agree that it is significantly easier to start with an iridium plug. Good advice, I shudder at the propects of not easily been in  a position to easily start the Maico on the start line. I once missed the start on a RM 450 when I stalled my RMZ putting on my goggles. By the time I got it started I was a lap behind and exhausted. Recently I have even considered the feasability of having road race rollers to help with starting. I am interested to hear the uproar that follows.

Keep it pinned.
Crabman

[VMX247]

http://ozvmx.com/community/index.php?topic=7229.0

Mr Crabman
If a rider has had a hip replacement they are the bees neeez     
cheers

[crabman]

Hi VMX

The solution to your problem  and Mine in contemorary times is an E button. Hence I bought a KTM 505 with an electric start.
I am hoping that the roller idea has merit. I am going to try and find something soon. I really appreciate the feedback.
Regards

[DR]

sorry to drag this on folks but Loz, the well used 30 year TS185 shocks (or shitters as you'd call them) got me 3rd overall in the pre'75 125cc 18-49 group at the Oz titles in '07. The rest of the bike was 100% bog stock standard. Would the trickest shocks in the world have made any difference whatsoever? simple answer from the only one who knows is absolutely not. There is a lot more to being fast than having the most HP and this is exactly what I am talking about. I'm not what I would consider a fast rider by any stretch of the imagination but I am consistant

[JohnnyO]

You are absolutely right Doc. Sheer horsepower in motocross is not so important as to the type of horsepower the bike puts out. Road racing might be different but half a horsepower in motocross is neither here nor there at our level.

[DR]

Thanks John, I really don't expect everyone will have the same perspective on these plugs and that's fine. Like I said they work for some and not for others so buy 1 make up your own mind kids but don't be swayed either way by what's written on the box, hear say or dyno sheets. The fact is you have to try it for yourself. To answer another question for you Loz, I bought the plug for the so-called unreal durability they supposedly had and not for any supposed gain in performance. I had all the performance and more  for the type of riding I was into at the time. Admittedly it was an NGK and not a Denso. At the time I was not interested in racing period but I did want a plug that was dependable when miles away from anywhere and a plug that would last and last. The plug did not last out the day before the old NGK was slotted back in for simple reason the iridium plug was too unreliable and troublesome to bother with in my old 400.

[Lozza]

  Doc. god love ya, your the ONLY rider in VMX that weighs less than a 125, that gives you a tremendous power to weight ratio advantage, plus your a reasonable rider, those 2 things give you a BIG advantage.Nor are you heavy enough to really trouble most shocks.Even a 70kg rider is giving you a 20kg advantage. So you don't have to make up for added weight with more HP or better suspension. As I've stated if a plug can display a gain on a dyno it will show a BIG improvement in throttle response or connection between the throttle and the rear wheel.That is something every racer aims for.
For every one of those stories I have another success story including converting trail riders more skeptical than yourself, one bloke thought his bike went better,got better economy but strangely thought he better stick with the $5 jobbie(same bloke knocked back a free V-Force  ) so I don't really care if you use them or not, I'm just putting forward some direct evidence(not opinion or hearsay) of what a plug can do for you.

[DR]

  bless ya too big Loz has been a fun topic