NGK Iridium spark plugs

[xlxr]

xlxr:   How is it that you feel the iridium spark plug makes the fuel mixture leaner?  I don't get it?

I am not sure "leaner" is an accurate or complete way of describing the effect of changing from standard to Iridium plugs.  Someone will have to post up before and after air fuel mixtures to see what is happening. 
Perhaps a more accurate description would be changing from standard to Iridium plugs changes the combustion process enough to be careful.  The guy who reported pipes getting too hot will have to check it out more and report back.
 

[peporter]

I install last week these spark plug CR9EIA-9 stock no. 6289. Start the CP3 engine and overheated pipes red after about one minute. 
Is there somebody who have or know the reason of this problem please.
 
Odometer at 10 600 km after one season.
 
Thanks for your help !

As other have hinted on here, there's nothing on the NGK site that would indicate that plug type has an effect on how hot the engine will run, rather that one has to select the right plug for the right temperature application. They also list some factors that WILL affect the engine run temperature (and thus affect the performance of the plug), and of course timing is one of them. Assuming that the plug itself cannot make the engine run hotter... was the plug swap the only task performed on this bike? No valve/timing work, ECU flash or otherwise? If not, could it be a bad plug and/or bad electrical connection, gaps not set right?

http://fj-09.org/search/results?captcha_id=captcha_search&display_as=0&page=2&search=Search&what_at_least_one=NGK%2BIridium%2Bplugs&who_only_made_by=0 About half way down the page is NGKs' response to me on the issue.
 

[eeetea]

I install last week these spark plug CR9EIA-9 stock no. 6289. Start the CP3 engine and overheated pipes red after about one minute. 
Is there somebody who have or know the reason of this problem please.
 
Odometer at 10 600 km after one season.
 
Thanks for your help !

As other have hinted on here, there's nothing on the NGK site that would indicate that plug type has an effect on how hot the engine will run, rather that one has to select the right plug for the right temperature application. They also list some factors that WILL affect the engine run temperature (and thus affect the performance of the plug), and of course timing is one of them. Assuming that the plug itself cannot make the engine run hotter... was the plug swap the only task performed on this bike? No valve/timing work, ECU flash or otherwise? If not, could it be a bad plug and/or bad electrical connection, gaps not set right?

That's not how I understood the NGK commentary,  
 
"...When you need your engine to run a little cooler, run a colder plug. When you need your engine to run a little hotter, run a hotter spark plug..."
 
 
 

[xlxr]

You guys are misreading what NGK is saying. The main purpose of different heat ranges is to maintain a proper temperature of the electrodes in order to burn off carbon deposits without getting so hot that pre-ignition / detonation happens. If you ride very easy, have too rich a mixture, too retarded timing,you need a hotter plug to keep its electrodes clean. The harder you run the engine, advance timing, less rich mixtures, a colder plug can be used ..... to prevent overheating caused by other factors such as too advanced timing and too lean mixtures that may cause melted pistons in worse case situations.
 
My point is, spark plugs do not work by themselves. Do not make assumptions that iridiums will always be a safe and direct replacement if something else is out of adjustment.

[bobaintstoppin]

Now we're starting to make some progress.  My point was that the spark plug does not affect the mixture in any way.  The heat range is pretty well described by xlxr above.  If the iridium plug is in fact a match to the spec plug there would be no effect on the combustion.  The plug would just last longer due to the higher spec materials in the electrodes.  
 
There are other things to consider in the plug match.  Heat range, of course, but also the dimensions of the plug.  How far it extends into the chamber etc.  For the most part a spark is a spark as long as it's enough to light off the fuel mixture.  A bigger spark (higher voltage etc.) can provide more consistent ignition.
 
Sounds to me like the NGK plug used by the OP might have more reach into the chamber and could be causing some overly fast lighting of the mix simply because it's in a different spot.  That might also  imply overheating the piston if it's too close to the piston top during a hard run.  you might want to check the other dimensions of the plug before assuming it's a good fit on our motor.

[clint]

Now we're starting to make some progress.  ..snippage 
Sounds to me like the NGK plug used by the OP might have more reach into the chamber and could be causing some overly fast lighting of the mix simply because it's in a different spot.  That might also  imply overheating the piston if it's too close to the piston top during a hard run.  you might want to check the other dimensions of the plug before assuming it's a good fit on our motor.

Here is a side-by-side of the two plugs. 

 

[bobaintstoppin]

A quick attempt at cross reference for the NGK 2308 gives Denso 5363 IU27 Iridium Power Plug at sparkplugs.com.  Will post up if I can find anything else.
 
Edit:  Then if you cross reference the Denso plug  you get NGK NGK 3521 CR9EIX IX Iridium Plug.  Is this the plug that was giving trouble?  Or a different one?

[xlxr]

 If the iridium plug is in fact a match to the spec plug there would be no effect on the combustion.  The plug would just last longer due to the higher spec materials in the electrodes.   
 

Compare $2 Champions to $10 Iridiums, and then come back and report.  I have tried a lot of different plugs over the years, most do not make a difference, but I did notice a difference between the far ends of the spectrum.  There are just too many complicating factors for your assumption to be true in all cases. 
Regardless, as a result of this conversation, I have decided what I am going to do.  I am going to replace the stock plugs with new stock plugs at the stock recommended interval.  I will do carb synch at the same time.  A big part of my reasoning is I simply do not want to do all the work needed to take the tank off and replace the plugs  and then take the tank off again to do throttle body synch on a different schedule.   Another big reason is to maintain warranty.  I will keep the old plugs until warranty is expired, and then reuse them if they are in good shape.
 
 

[CocoST]

For your information,
 
Following the installation of new stock spark plugs according to specifications, the problem of overheating of the exhaust has returned.
 
Having mechanical limitations, my local dealer Yamaha will proceed to a tune-up in order to find the source of the problem and to return to its normal functioning soon.
 
You will be informed of the continuation and cause.
 
Thanks for all information and research

[xlxr]

I heard back from Nels at 2WDW:
 
Thank you for the email. The iridiums will work great and last longer. I assume Yamaha didn't use them to save money at the factory. Have a great one! Nels
 

[xlxr]

I finally got around to reading some of the threads about Iridium spark plugs on FZ 09 forum. Most guys said they worked good, but there were a few reports of various problems after switching to Iridium plugs. Not really enough detailed information for me to spot specific trends causing problems.

[clint]

I changed the spark plugs and air filter today at around 12,300 miles. I used the NGK Iridium CR9EIA-9 and stock air filter. The stock copper plugs were colored perfectly and could have certainly lasted 20,000 miles. It only took a couple of hours working meticulously....not hard at all really. The bike fired right up with the iridiums and I'll take it out for a few hours tomorrow.

[advman]

Gonna replace the plugs on mine soon, is it easy to remove the tank? Do you disconnect everything and completely remove it or just enough things to rest it to one side? TIA

[xlxr]

http://fj-09.org/thread/1239/removing-fj-09-ecu
 
Here is one thread showing how to remove plastic and tank. I turned the tank around backwards and put it on boards because I was also synching the carbs. I had to disconnect the vacuum tubes and fuel pump electrical connector to turn the tank and then reconnected the electrical connector. Put some tape on the black frame under the bottom edge of the tank to keep it from scratching the frame.
 
There are other threads and a video somewhere.

[advman]

Spot on 8-)  just what I was after.... Thanks