Spark plug choice...

[TownsendsFJR1300]

That was me. In my particular case I found that performance and mileage decreased over a 10,000 mile interval to the point of having misfiring under load. After changing back to the standard NGK plug all of my problems have disappeared.

The thread in question: http://www.600riders.com/forum/fz6-technical/44482-poor-mpg-things-not-always-they-appear.html

I knew that!!! Actually I remember the thread obviously but not the poster,

You didn't happen to check the gap of the iridiums when you took them out and see if the gap opened up some (with wear and tear)?

 

[Red Wazp]

That was me. In my particular case I found that performance and mileage decreased over a 10,000 mile interval to the point of having misfiring under load. After changing back to the standard NGK plug all of my problems have disappeared.

The thread in question: http://www.600riders.com/forum/fz6-technical/44482-poor-mpg-things-not-always-they-appear.html

John, I wonder if you didn't have a bad plug. Never heard of a iridium fail like yours in such short mileage.
I have well over 25k on two sets in my Feejeer with no performance issues.

 

[mave2911]

John, I wonder if you didn't have a bad plug. Never heard of a iridium fail like yours in such short mileage.
I have well over 25k on two sets in my Feejeer with no performance issues.

I've noticed an obvious and dramatic decrease in fuel efficiency since changing to the Iridium plugs.

One observation is that the standard copper plugs are dual pole negative, so adjusted correctly, this should result in a more complete combustion.

Also, apparently Iridium isn't as conductive as copper, so there will be potential losses there too.

I'm giving the Iridiums a decent run, but they've been in there for nigh on 10000kms (6200mi). My 'major' service is due in 4300kms (or thereabouts) and I was thinking of putting stock NGKs in two tanks before the service - just to get an acceptable sample size.

If it instantly increases, I'll have two tanks, or 8 days travel to work to get a result.

That way, at or after the 40000kms service, I'll know what I want to run.

Cheers,
Rick

 

[PhotoAl]

Someone asked about the E3's - junk! My son put them in his Vibe GT which has a high output Toyota motor. Ran rough, gas mileage was not improved which is a big deal for a grad student. When he came to visit I swapped out for platinum plugs which ran much better and got rid of the rough idle.

Ran stock NGK plugs changed to iridium plugs, much smoother idle could not tell much difference in performance at 28,000 miles went back to stock NGK (what the dealer had in stock) and have not noticed any real difference.

 

[Darth Fazer]

Don't the OEM spark plugs have a double ground strap or something goofy like that? Does that make a difference? Can you get that with an aftermarket plug like NGK or do I have to get those dual strap plugs from the dealer? Who makes the OEM?

 

[Motogiro]

I mentioned on another thread that the factory settings for the gap on the Iridiums was greater than the specified setting for my SV10000s. One catch all gap for a plethora of different applications of that same plug! I opted to set my Iridiums to the gap specified for my bike's manufacturer. I was also very careful not to put mechanical pressure on the tiny Iridium tip, moving only the ground tang and using a wire gauge to set the gap.
That tip is laser welded in place. If you damage the tip, install the plug and that little Iridium tip breaks, you could be in for some expensive bad news. This may be why there is one size fits all gap.

Proper gap and combustion efficiency is predicated on a few factors and I think the primary consideration is the coil secondary voltage. After that there is compression ratio, RPM, heat range, A/F ratio etc.

With lower secondary coil voltage you will need a smaller air gap. With higher coil voltage you can use a wider air gap. Coil voltage is related to the air gap between the center electrode and outer/negative electrode.

I think the advantage of the Iridium plug is the very small target area the spark hits to complete it's journey. I believe the theory is this creates a more accurate spark in the same spot with less variation. This would also create a smaller concentrated area for the same amount of electrons to travel in
This is probably why they use the tiny Iridium tip. A small softer alloy would loose metal very quickly in an application like this. A larger target area provides a more varied target and less consistency of spark and may also have more variation under compression.

This Youtube is in Russian but the outcome is a test under different amounts of compression between a standard plug and an Iridium plug. The Iridium plug wins in this comparison but is it the right all round plug choice?

This test may mean nothing. The stock plugs are fine and maybe even better all round performance for our bikes.
We fall for many marketing gimmics and I believe there are many variables in applications to consider that may not be obvious in the beginning.

In this test are the gaps set the same? Is the guy using the same secondary voltage? Is the compressed gas the same properties as air to fuel ratio gas in an engine? Is he selling more expensive Iridium plugs? These are all factors in our science today.

[video=youtube;wbuGpJWNX1M]https://www.youtube.com/watch?v=wbuGpJWNX1M[/video]

 

[Guitar Man]

In that video the first plug looked like it was pretty well used. I wonder if the same plug new would look any brighter? Seems like they could have done a better comparison.

I use the standard plugs. My bike runs like a top and is all stock. I can tell the difference in performance after changing the plugs at 8,000 miles. The resistance changes over the life of the plug. I don't bother to check them at 4k like it says to do if the bikes running normal.

I figure the engineers knew what they were doing when they designed the engine. I'll stick with that.

 

[Motogiro]

In that video the first plug looked like it was pretty well used. I wonder if the same plug new would look any brighter? Seems like they could have done a better comparison.

I use the standard plugs. My bike runs like a top and is all stock. I can tell the difference in performance after changing the plugs at 8,000 miles. The resistance changes over the life of the plug. I don't bother to check them at 4k like it says to do if the bikes running normal.

I figure the engineers knew what they were doing when they designed the engine. I'll stick with that.

If the comparison was the same amount of atmosphere pressure and the spark voltage is the same, the comparison is pretty impressive. You can see as the compression increases the Iridium seems to continue to fire where the other plug fails.
My message is mainly set the plug you're using to the factory Yamaha FZ6 spec. for the gap, what ever plug you use.

 

[Guitar Man]

^^^ Right.

 

[philz]

I recently replaced my stock plugs with NGK iridiums. If I'm totally honest I can't tell any difference but the price difference was negligible so I thought I'd give them a try.

I also use NGK iridiums in my car too. Can't tell the difference in that either.

Maybe it's marketing hype, maybe not but for a few quid difference it's worth a try.

 

[Motogiro]

I recently replaced my stock plugs with NGK iridiums. If I'm totally honest I can't tell any difference but the price difference was negligible so I thought I'd give them a try.

I also use NGK iridiums in my car too. Can't tell the difference in that either.

Maybe it's marketing hype, maybe not but for a few quid difference it's worth a try.

Interested in whether you set the plugs to the OEM spec. or did you just install them as they were set out of the box.

 

[aussiejules]

Be extremely careful with both iridium and platinum, about check gaps on them. It is preferable not to touch the electrods so as not to scratch or damage the coating. I remember when i was a apprentice and i changed platinum to standards in a 10 000km service on a tarago(not knowing better, first platinum plug our dealer ship had seen), and for days customer said vehicle wasnt right, untill we changed back.

 

[carbonar1]

Irridiums have a longer service interval, there is no performance benefit.

Standard NGK's are designed to last 12 to 17,000kms. Irridium 24,000 kms.

The gap is the important part. :thumbup:

 

[stink989]

the ngk website says 40-50k miles or 80k-130k km (rough convert) for iridiums.i woulnt leave them in a bike that long but sure would in the car.
How Long Do Iridium Plugs Last?
Most yammy manuals state spark plug change at 20k kms and normaly when I have pulled them out they are worn but still ok (still put new ones in though)

 

[Karate.Snoopy]

My MPG's have been dropping faster than my jaw at a sushi bar
Using the search I came across the following thread

Iridium Plugs and MPG's

I replaced the stock plugs with Iridiums on my bike last year when I bought it, unfortunately I never got to measuring the MPG's before replacing the stock plugs.

I have recently replaced the air filter with the K&N filter. Have adjusted,lubed the chain, checked for rear brake drag and done an oil change. The MPG's are still hovering close to 34 miles per Gallon. Don't think we have winter gas here in New England even though it was close to freezing this morning.

Beginning to wonder if the Iridiums have something to do with it and may be I should switch back to stock

 

[Motogiro]

Re: Re: Spark plug choice...

My MPG's have been dropping faster than my jaw at a sushi bar
Using the search I came across the following thread

Iridium Plugs and MPG's

I replaced the stock plugs with Iridiums on my bike last year when I bought it, unfortunately I never got to measuring the MPG's before replacing the stock plugs.

I have recently replaced the air filter with the K&N filter. Have adjusted,lubed the chain, checked for rear brake drag and done an oil change. The MPG's are still hovering close to 34 miles per Gallon. Don't think we have winter gas here in New England even though it was close to freezing this morning.

Beginning to wonder if the Iridiums have something to do with it and may be I should switch back to stock

When you switched to the Iridium did you set the gap on the plugs to FZ6 factory setting? The gap on any plug should be set to spec. and the NGK or any plug may not be the right gap. I'm running Iridium set to factory gap on my SV1000s and my mileage and performance are great!

Sent from Moto's Droid using Tapatalk 2 :mikebike:

 

[Karate.Snoopy]

When you switched to the Iridium did you set the gap on the plugs to FZ6 factory setting? The gap on any plug should be set to spec. and the NGK or any plug may not be the right gap. I'm running Iridium set to factory gap on my SV1000s and my mileage and performance are great!

Sent from Moto's Droid using Tapatalk 2 :mikebike:

I had a mechanic (does home visits) do it in my garage and I don't think he set the gap. If I were to switch back to the NGK CR9EK, would I still have to adjust the gap according to the factory spec? Seems safer and cheaper to try this out.

 

[dpaul007]

The gap on any plug should be set to spec. and the NGK or any plug may not be the right gap

I had a mechanic (does home visits) do it in my garage and I don't think he set the gap. If I were to switch back to the NGK CR9EK, would I still have to adjust the gap according to the factory spec? Seems safer and cheaper to try this out.

Motogiro already answered that question. :thumbup:

 

[Karate.Snoopy]

Motogiro already answered that question. :thumbup:

Too eager at this end , I am not too mechanically savvy and a bit on the lazy end of the spectrum. Isn't there a stock spark plug set that has the correct gap off the shelf?

 

[Motogiro]

One of the reasons gap could be twice as important on our bike is it uses 2 coils for 4 spark plugs. One coil for #1 and #4 cylinder and one coil for #2 and #3 cylinder. What happens is the coil fires at TDC and the end of the exhaust stroke for each piston that is mechanically at TDC and end of exhaust stroke. In other words pistons #2 and #3 are both in the same position in the cylinder but they are at opposites in firing and exhaust. One being the end of compression and beginning of power. The other cylinder would be the end of exhaust and beginning of the intake. So the coil is firing twice as many times as a coil that is dedicated to one cylinder. Dielectrically there is more stress on the coil pack because the path for it's spark has been increased. It is more likely to create corona (with increased gap) internally and break down internally or when there is an insulation problem it may more readily take that path and not produce a strong or weak spark where we want it. The coils are looking a 2 plugs... Be careful setting the Iridiums!
Set your gap to factory specs!