spark plugs


26 replies to this topic
  • deano0

Posted August 07, 2007 - 02:35 AM

#1

i was justing wondering what spark plug i should run in my yz426? at the moment i am using a standard NGK cr8e spark plug, but i was curious as to see if i should b using a platnam or iridium spark plugs. what do u guys use in ur 4stroke bikes?

thanks boys... :):)

  • fishpost19

Posted August 07, 2007 - 04:15 AM

#2

Stick with standard. :prof: Apparently (I've read this on other forums), the expensive iridium/platinum that you mention, are no better than standard plugs (for bikes that is) so you will just be blowing your money on expensive plugs with no gain . Standard plugs will last ages in four strokes. Just stay with standard NGK plugs.

Happy riding! :ride:

  • 642MX

Posted August 07, 2007 - 04:18 AM

#3

The CR8E is fine. The iridiums are a waste of money. I've tried them and have found absolutly no advantages over the regular plug.

With that said, I've been using a CR8EK from the beginning of this year. I've found that the bike seems to start better cold, which doesn't make a whole lot of sense, but so far so good. :thumbsup:

  • 00YZ426FMRCD

Posted August 07, 2007 - 05:26 AM

#4

FYI: If you order your plugs thru your Autoparts dealer, you can save 2-$3 per plug versus buying from a local MCycle dealer.

- RCD

  • deano0

Posted August 07, 2007 - 02:19 PM

#5

thanks guys, appreciate your help.

yeah i get my spark plugs from an auotparts dealer, i wrk there so its even better advantage..

anyway thanks for the help g0od job :):):);p

  • Yamaha4lyfe

Posted August 07, 2007 - 03:11 PM

#6

i want a glow plug in my bike. o and i want a diesel engine haha:cry:

  • almostinvincible119

Posted August 07, 2007 - 06:17 PM

#7

The CR8E is fine. The iridiums are a waste of money. I've tried them and have found absolutly no advantages over the regular plug.


My bike fires better with the iridium. Hot and Cold. I also run c12.

  • 642MX

Posted August 07, 2007 - 06:47 PM

#8

My bike fires better with the iridium. Hot and Cold. I also run c12.



Fires better? Whats that mean?

  • 642MX

Posted August 07, 2007 - 06:53 PM

#9

FYI: If you order your plugs thru your Autoparts dealer, you can save 2-$3 per plug versus buying from a local MCycle dealer.

- RCD


Good point. :thumbsup:

  • deano0

Posted August 08, 2007 - 01:41 AM

#10

My bike fires better with the iridium. Hot and Cold. I also run c12.



what do u mean??? does it start more easy? runn betterr while ur riding... please explain

tanks mate:ride:

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  • almostinvincible119

Posted August 08, 2007 - 05:29 AM

#11

i mean, its a one or two kick bike all the time. hot or cold. it also has a slightly better response off the bottom. the standard cr8e has a bog with me. but as long as you dont crack the throttle, it is hard to tell. jet your bike right and you should be fine on throttle response. the VP c12 makes the bike a little harder to fire when hot, but anyone who doesnt think that an iridium plug doesnt make a difference is too lazy to spend the extra 2 bucks.

  • 642MX

Posted August 08, 2007 - 08:25 AM

#12

but anyone who doesnt think that an iridium plug doesnt make a difference is too lazy to spend the extra 2 bucks.


There is no performance gains with iridium. Iridium plugs may last longer than a conventional plug, but who cares? a standard plug will easily last a year or longer. :prof:

I don't believe that an iridium spark plug will cure a bog issue either. :naughty:

  • almostinvincible119

Posted August 08, 2007 - 09:00 AM

#13

well. it does, i dont know what kind of fuel your running, but it sure isnt vp. we also change my plugs on my bikes every 2 months. im not saying it solves bog problems, but it does improve the response. running one plug for a year is crazy. Yes, it will last one year, but it doesnt ness. mean its good for a year. i put about 100 hours on each of my bikes in about a year. and if your riding lazy, then maybe a year is fine for the plug, but not when you start puttin seat time in.

i can agree with you on saying it doesnt offer any performance gains...but have you tried an icat? the dyno doesnt register its "performance gain" on that. i have a friend who has one and he loves it. i think a 200 dollar spark enhancer is a waste though.

but, not everyone can tell the iridiums apart from the standard plugs. but if your running race fuel, it makes a difference in starting while hot.

I also see that 642mx is riding a 426. maybe those things start great while hot all the time! :)

  • 642MX

Posted August 08, 2007 - 09:12 AM

#14

but, not everyone can tell the iridiums apart from the standard plugs. but if your running race fuel, it makes a difference in starting while hot.

I also see that 642mx is riding a 426. maybe those things start great while hot all the time! :)


I've ran race fuel since my bike was new. I started with Citgo 110, went to Monster race fuel and now I use Sunoco 110. I also run a 13.5:1 piston, hot cams, and my rims are blue.......none of the mods (or the race fuel) require me to use a iridium plug.

And yes, my 426 starts perfectly when hot. I hardly ever use the hot start either.

BTW, icats are a waste of money. Why would you need a more intense spark?

A spark plugs job is to ignite the air/fuel mixture when the piston compresses the mixture. As long as the spark occurs, the engine will run. And it doesn't take an overpriced plug to ignite an air/fuel mixture....... a cheap one will do fine. :thumbsup:

  • grayracer513

Posted August 08, 2007 - 09:25 AM

#15

Iridium, platinum, and other alloys are used to improve spark plug performance by reducing the resistance to the flow of electricity in the plug itself. This can make a very noticeable difference in older bikes with weaker ignitions. The 426 has less spark energy than any of the YZ450's, so it falls into that category to some extent.

The center electrode is the one designed to eject the electrons during the spark event because it is the hottest (normally) part of the plug; it is easier to emit electrons from a hot surface, because of the same physical laws that increase emissions of vapor from hot surfaces (Thermionic emission). Also, the strength of the electrical field will be the greatest wherever the radius of curvature of the surface is smallest, like a sharp point or edge rather than a flat surface, and it is from this point that the spark will jump. A pointed electrode would be electrically superior, but a pointed electrode would erode after only a few seconds. Instead, the electrons emit from the sharp edges of the end of the electrode; as these edges erode, the spark becomes weaker and less reliable.

The use of precious metal high temperature electrodes using metals such as iridium, platinum, tungsten, or palladium, and others, allows the use of a smaller center wire, which has sharper edges but will not melt or corrode away as quickly. The smaller electrode also absorbs less combustion heat.

So, at least in theory, iridium plugs will last longer, will be less prone to misfire, and contribute to more reliable starting, especially in an engine with marginal ignition strength. In practice, ordinary plugs will work very well for a very long time in most modern 4-stroke motorcycles. Both of mine are about a year old at this point.

  • deano0

Posted August 09, 2007 - 02:48 AM

#16

i havnt had any problems starting when cold, starts with in 2 - 3 kicks.. the only time its hard is when it becomes fl0oded. apart frm that starts g0od when hot aswell. i think ill stick with the stanard plugs for now, mite even give a cr8ek ago see how that g0es...

anyway thanks guyss

  • mr426

Posted August 13, 2007 - 08:59 PM

#17

what is the diff between the cr8ek and the cr8e?

  • Art_H

Posted October 03, 2007 - 10:48 AM

#18

:confused:

what is the diff between the cr8ek and the cr8e?


CR8EK has two ground electrodes. They shroud the spark kernel and provide shrouding to the fuel/air. And no, it doesn't spark to both grounds at the same time. IMO, the there is no reason to run a 'K'. But I have never used one to see a diff. However the physics are in favor of only one ground.

Iridium, platinum, and other alloys are used to improve spark plug performance by reducing the resistance to the flow of electricity in the plug itself. This can make a very noticeable difference in older bikes with weaker ignitions. The 426 has less spark energy than any of the YZ450's, so it falls into that category to some extent.

The center electrode is the one designed to eject the electrons during the spark event because it is the hottest (normally) part of the plug; it is easier to emit electrons from a hot surface, because of the same physical laws that increase emissions of vapor from hot surfaces (Thermionic emission). Also, the strength of the electrical field will be the greatest wherever the radius of curvature of the surface is smallest, like a sharp point or edge rather than a flat surface, and it is from this point that the spark will jump. A pointed electrode would be electrically superior, but a pointed electrode would erode after only a few seconds. Instead, the electrons emit from the sharp edges of the end of the electrode; as these edges erode, the spark becomes weaker and less reliable.

The use of precious metal high temperature electrodes using metals such as iridium, platinum, tungsten, or palladium, and others, allows the use of a smaller center wire, which has sharper edges but will not melt or corrode away as quickly. The smaller electrode also absorbs less combustion heat.

So, at least in theory, iridium plugs will last longer, will be less prone to misfire, and contribute to more reliable starting, especially in an engine with marginal ignition strength. In practice, ordinary plugs will work very well for a very long time in most modern 4-stroke motorcycles. Both of mine are about a year old at this point.


Exactly.

The physics supports an iridium plug. The NGK IR has an electrode that is
0.6mm. The Denso IR has one that is 0.4mm. The bottom line is that the most disregarded parts of engines is the ignition, and without it, nothing works. You may not notice a diff when you only have 50 HP, but a V8 running 500+ is gonna feel it. There are benefits that are not obvious, better starting for sure, longevity=reliability. Maybe try opening up the gap on an Iridium and then see a better gain. If you don't think Ir plugs make a diff, then you might as well go back to drum brakes!!! :confused:

The Ir should foul less as well, as there is a more complete burn right near the plug. however, excess blowby and heavy overfueling will foul any plug.

Putting Ir in my 05 R1 woke it right up... a big difference in power, throttle responce, and mileage.

Art

  • grayracer513

Posted October 03, 2007 - 11:39 AM

#19

You may not notice a diff when you only have 50 HP, but a V8 running 500+ is gonna feel it. There are benefits that are not obvious, better starting for sure, longevity=reliability. Maybe try opening up the gap on an Iridium and then see a better gain. If you don't think Ir plugs make a diff, then you might as well go back to drum brakes!!!

The Ir should foul less as well, as there is a more complete burn right near the plug. ...

Putting Ir in my 05 R1 woke it right up... a big difference in power, throttle responce, and mileage.

A 5.7 liter V-8 producing 500 hp is creating almost 88 hp per liter, and not quite operating at the level of a 50 hp 450 producing 111 hp/l, for one thing.

Again, the benefits of Ir or other precious metal plugs, apart from their longevity, are only a factor in engines with marginal ignitions that have difficulty in providing a good, strong spark with a conventional plug. If this can be achieved, there's no particular advantage.

There is also no foundation for any claims of more complete combustion except in the case where the engine actually fails to ignite the fuel charge and misfires. All the plug can do is start the fire. It's up to the fuel itself, and the design and performance of the fuel system, timing, and combustion chamber as to how completely it burns.

And any engine will respond to a fresh set of plugs with the crisp performance you noted in you R1 (killer bike, BTW), regardless of plug type. But the Ir plugs will keep their performance level up for significantly longer.

  • Art_H

Posted October 04, 2007 - 11:07 AM

#20

grayracer,

All of what you are saying has merrit, though I do believe that there is more to Ir plugs.

My point about the 500hp V8 vs the single cylinder engine was more to show an example of a percentage improvement. 5% @ 500 hp is 25 hp. 5% @ 50 hp is 2.5 hp. a 2.5 hp difference is difficult to see on a dyno, and you may notice more on the seat of your pants comparison.

I agree with you that the Ir plugs will mostly assist with a poor ignintion system. Especially if you just keep things stock. ie; plug gap. (0.031" WR426) If you have a strong ignition, there is no reason that you cannot open up the plug gap. Starting with a larger gap (if you can jump it) will give you faster combustion. If you look at the time lag on a graph of flame propegation, the spark kernel growth is very slow up until about 0.100". At that point the graph just shoots almost straight up. Ultimately you will have to adjust your spark curves to fully take advantage.

What some racers have done to their steel plugs, is file down the positive(center) electrode down to a point. This achieves the same thing as an Ir plug, But obviously doesn't last that long.

there is a lot of tech in ignition, and still a lot of unknowns. What is known is that a larger initial spark, will burn the fuel/air faster, and when it needs to burn quick at 12000RPM, that makes a difference.





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