Spark Plugs - How long do they last?

[anonstarter]

Halfabusa's post http://www.maxi-muppets.co.uk/forum/vie ... =5&t=13021" onclick="window.open(this.href);return false; got me wondering - how long do spark plugs normally last?

What are the symptoms of a failing spark plug?

Have you replaced a working spark plug and thought "Feck me! Why didn't I do that sooner!"

I've got a NGK CR8EIX 4218 Iridium IX - that's 'apparently' the 'dogs goolies' of spark plugs(?)- just waiting for the 12,000 mile service. Is it worth me fitting it sooner?

As always thanks in advance!

[pikey]

I d say just carry a spare iridium should last double standard .Its more Im changing them and old one looks Ok with plugs what ever manufactures say plus 50 % Id say as they are over cautious

[Sylar]

I used to change my plugs at recommeded intervals, until i was told Iridium plugs should last 50,000mls. I fitted Iridium plugs (2) in my Silverwing at 8,000mls. Ordinary plugs would be due change at 16000mls. At 16000mls i checked the plugs, they didn't need cleaning and the gap was spot on. At 24,000mls i checked them again and again clean as a whistle and gap spot on. I normaly get about 64mpg and i still get that, so, plugs are doing thier job okay. My advice, definately put Iridium plugs in, i paid same for Iridium's as i would have for ordinary plugs so, iam quids in.

[Data]

Yes, with Sylar on the Irridiums. They are good and I'm going that way myself at next service with the Burgman. Just one thing to be aware of in case anyone is unsure. Bike manufacturers and spark plug makers, although a little over cautious on the miles they recommend for a change of plug, do so for a very good reason. As a spark plug covers more and more miles, it's efficiency reduces due to the gradual breakdown of the plugs internal insulation. This causes a gradual increase in resistance within the spark plug. This does two things. It reduces spark size, although not too much in the first instance, but it also increases the amount of voltage required to 'fire' the plug. A true example of this is as follows: a CR8E ngk plug at 10,000 miles requires normal voltage to fire it. At 20,000 miles even with the correct spark plug gap, it requires 50% more voltage to fire the plug due to increased resistance. The net effect of that is a more sluggish engine, usually not noticed at first by the rider, and a drain on your electrics at various times during start up and at other times as you ride. It also hammers the coils or ignition module causing it to run much hotter than it should. You will also lose engine fuel efficiency due to a less strong spark. The electrode at the spark plug tip gives only a partial indication of how worn the spark plug is. It's the bit you cannot see inside the plug that just as much determines when the plug should be replaced. Running a spark plug beyond its designed life span is ok for just a little but is nearly always false economy and of course you have an increased risk of plug failure from electrode failure (maybe damaging your engine) or other internal problems in the plug. After a service, many owners notice a nice increase in performance if the plug/s have been changed. It can be very noticeable.

[Dave Weller]

http://www.densoiridium.com/spconstruction.php" onclick="window.open(this.href);return false;
Item 3, the glass copper seal could be a stress failure point.

[Data]

Yeah...Dave you are right! When we were engine testing, we had considerable advice from the 'eggspurts' on a number of potential issues that would likely occur during prolonged bench testing. The spark plug bods were brilliant. Even to the point they were able to supply us with very detailed information about how their plugs would react to what we were doing, the temperatures, voltage requirements after X number of miles, the coil packs performance and heat degradation etc etc so we could build this data into our computer model that would run the engines over the 3 solid weeks of testing we were undertaking. Every single aspect of the engines was monitored in every way. It was pointed out that the glass copper seals develop cracks over time, leaching current and eventually leading to failure. We were advised to change plugs regularly to prevent engine damage at the higher rpm we were running them at. Not all plugs use the glass copper seals but we wanted the quality they afford. Following their advice, we didn't get any problems at all and the tests were a success.

[anonstarter]

You're a star Data -thanks for another great informative post Sir!

You'll never guess what I plan to do this weekend!

[Data]

Errr....let's see! You're going to have a beer...whilst changing your spark plug? Don't spill any!

[michaelphillips]

Hi, just a twist on spark plugs to get you all thinking, i have tried the standard and iridium plugs, yet for the last 3 months i have used a AOR14LGS Brisk racing performance plug, the plug should never need replacing as my scoots done 40,000 miles and the plug standard life is 25K mile - 40K Km or 500-600 hours lifespan, and you dont set the gap either, Center Electrode Material Silver – The material with the most free electrons. Silver is by far the best thermal and electrical conductor of all metals. have a look at http://www.briskracing.com/brisk-racing-lgs-spark-plugs" onclick="window.open(this.href);return false; they claim a % boost alround, if i can just tell you my expierience in 3 months, about 1.3 mpg more, but i only do 10 miles stints on traffic, and the scoot is smooth as silk, what i found which i could not get with the iridium and standard plug was throttle stability at any revs, i mean virtually no throttle and hold a permanent rev say 3100rpm or 4400 rpm etc.
my gilera nexus 500 runs as follows
Sprint High Performance Moto air filter SPECIAL DRY POLYESTER type It can be cleaned more easily and reinstalled immediately thus saving the cost of the specialist cleaner and oil and works out cheaper over a longer period, plus the added benefit of improved COLD air flow means increased power.
Polini Evolution Maxi Clutch Bell and a 5 shoe clutch instead of the standard 3 shoe.
Dr Pulley 24gm weights
i can honestly state that the plug change was the best plug i have ever used, not one hicup in last 3 mths and its smooth and i can hold any rev as long as i like on minimal throttle , and the responce is instant but its always a joy to ride.
i bought mine from a firm in america, around £16 delivered, i have noticed a company in uk does the same LGS spark plug £13 deliverd from here
http://www.ebay.co.uk/itm/360394108178? ... 1438.l2649" onclick="window.open(this.href);return false;
He does other premium LGS plugs for all other scoots if you email him your scoot, so what do you all think????

i would never buy another type again, unless i have to, sorry about spelling etc
well worth the punt!!! i can answer any other questions i may have missed off, i have started another thread in the Garage cheers michael

[Data]

Micheal, glad you are getting on ok with that plug. Sounds a good un! Would be good if you can post back from time to time to tell us how it continues to perform.