NGK Iridium spark plugs

[clint]

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

Tank should come off. @nsmiller posted a YouTube Video recently on how to replace the spark plugs. Very well done. 
I've ridden 3 of the past 4 days here in NC and these plugs are great. Really no difference in the stock ones, but should last a lot longer!

[danielvdeleito]

Ok Guys. I want to try to explain my experience which I think is the conclusion for this post. I'm not professional mechanic but I have lot experience with mechanic and engineering.
 
The science:
The only difference between standard and iridium spark plugs is the material and size of the tip.
Iridium spark plug: smaller tip size but better material = This better material prolongs the life of the spark plug and avoid corrosion and carbon, but have a cost: the smaller size require more "energy" from your stator/battery. In a car with a regular alternator is not a problem, but motorcycles using extra compact stators is a big deal.
 
The history:
Since I install iridium SP in my FJ-09, it takes more cycles from the starter to start. With standard SP take 1/2 to 1 cycle to start and with iridium take 20-30 cycles. Also, when the motorcycle is on idle, the engine have poor or missing explosions (this explain overheat exhaust temperature). After 3.000 miles my battery die due the power consumption and the over duty use on each start (I'm everyday rider, so I start my motorcycle 2 to 4 times per day). Also my fuel consumption increase a 20% more.
 
The conclusion:
This is the reason why neither Yamaha or NGK recommends Iridium SP to some motorcycles. Instead, according the shop manual, they recommend replace SP every 12.000 miles
 
I hope this information helps everybody.

[xlxr]

Most guys do not report the same problems you have, so I doubt the plugs are the only problem. I suspect your air/fuel mixture is too lean, and the Irridium plugs push it over the edge. You may have other problems such as air intake leak, or air injection system not working properly. I have tried Irridiums on another bike, but not on my FJ 09 because I had 2WDW reflash when new and my original plugs looked very clean at 6,000 miles, so I stayed with stock plugs.

[crempel]

FWIW, I have 26,000 miles on mine. I ride it every day. It has the original plugs and the throttle bodies have never been synced. I am taking it in to get the valves adjusted next week, at which time I will likely replace the plugs. It runs perfect and smooth. None of the vibration that some complain of. I often find it entertaining how much some people worry about the wwwaaaaayyy long term maintenance and effect of things like plugs and synthetic or non-synthetic oil on a bike they will keep for 3 years and 12,000 miles at best. Did a trip from NC to St Louis in July and not at all sparing the whip, got 52 mpg. Change oil, put on tires, and ride baby ride.

[skipperT]

Ok Guys. I want to try to explain my experience which  
***snip***
 
The conclusion:
This is the reason why neither Yamaha or NGK recommends Iridium SP to some motorcycles. Instead, according the shop manual, they recommend replace SP every 12.000 miles
 
I hope this information helps everybody.

 
Interesting but I’m not sure I can get on board with this part of your argument.
 
-HD recommends Iridium plugs on their 120R motors.
-Honda ships lots of different models with Iridium Denso or NGK’s. Various CBR models, VtX1800’s, CRF1000 and cr and crf dirt bikes - IIRC
 
That’s all just off the top of my head. But Honda I know recommends a 16k mile replacement interval.
 
IIRC Yamaha incorporated a slightly more powerful stator onto the fj09 vs the fz09 because they guessed that the typical FJ09 buyer would tend to run more accessories on the fj09 thus putting more of a demand on the bike’s charging system.
 
I’m not convinced your running issues are related to the plugs.
 
Other thoughts?
 
-Skip
 

[danielvdeleito]

Thats correct. Exactly as you say many Motorcycle companies recommend iridium SP, but this not depends of the manufacturer. Depends of the model. This is why Yamaha DO NOT recommend on the fj-09 even with a bigger stator.
The stator send energy to the electric regulator and this to the coil (in modern engines is an electronic coil). The coil is preseted with an specific amount of power to each spark plug. The preset amount of electricity come from the energy consumption coefficient. If the spark plugs are running with a poor spark, you have a lack of power producing extra battery consuming and poor combustion in the chambers, which produce "rich mixture explosions" which produce excess heating.
This kind of issues are not big deal in Standard engines, but in crossplane engines (like the FJ09) is other history.
 

[Buggy Nate]

I think you are giving simple spark plugs too much credit. They are simply there to ignite a mixture. They cannot change the 'mixture'. They can have an effect on engine temperature if the incorrect heat range is used.
I would rather stock plugs as I actually think the iridiums don't last as long, as soon as the precious metal is eroded in normal use they tend to wear down very quickly.
If there was a standard replacement for them all our customers preferred the standard style.

[skipperT]

Plus regular old plugs are cheaper.
 
Until someone shows me a proven increase in hp/tq/ air fuel on a dyno chart with the only change being spark plug type - I’ll use what the manufacturer recommends. Any benefit of switching “up” to Iridium is speculation.
 
@daniel - part of the available output to fire the spark plugs is also determined by the inner electronics in the ecm and by the particular coil packs used in a given application.
 
You can (and I have) measure the peak firing output at the plug and at the coil pack in kV, with a peak reading voltmeter or utilizing a scope. Another experiment would be to measure that V with both Iridium and Non Iridium plugs to see if there’s a significant difference between the 2.
 
Honestly, a weak battery will have a greater effect on spark plug output than total stator output or spark plug type - as long as the charging system is healthy - in my humble opinion.
 
-Skip

[xlxr]

Let me correct myself and change air/fuel ratio with the term "combustion efficiency". Spark plugs can change "combustion efficiency", but there are other considerations that also affect combustion efficiency, air fuel ratio, compression, timing, temperature, etc. There have been a few other reports from some guys who have the same problems with Irridium plugs, and other guys report no problems at all. I have never read a detailed, and correct, explanation of all the different factors involved, what the problem actually is, or what to change to fix it.

[alquimista]

I used to have a tenere xt660z. When changed to ngk iridium you could feel the difference : more power, less heat. Now in FJ09 no difference can be noticed. Same as standard plugs.

[chitown]

Been running iridiums for 5k miles. The 40k rated version, not the 80k rated version with platinum tip. Without a dyno not claiming any performance change. Simply wanted longer service interval and less times to handle/stress/pull those coil-on-caps that look like they could be damaged if ham-fisted.

[betoney]

Did a trip from NC to St Louis in July and not at all sparing the whip, got 52 mpg.

I dont want to derail the thread, but please share what kind of special concoction you use to achieve such MPG.  Yesterday I was returning from a road trip and was riding a long straight highway back across the state, it was a beautiful Fall day with zero traffic, so I decided to take my time.  I set the cruise control at 60mph and rode for a few hours purposely trying to see what my fuel consumption would be; 6th gear, mid 4k rpm's, almost zero elevation changes, riding like a little old lady and I barely got 50mpg. 
I have no intake or exhaust mods and just the standard 2WDW flash. 
 

[eeetea]

I get better Mpg than that, up to 60, with regular plugs. The secret is to fill up in English gallons ( 20 fl oz)

[rain]

Something rarely mentioned in the MPG thread is WHAT YEAR THE BIKE IS.
15-16's are one thing, the 17 supposedly has different mapping. I have an off the shelf 17, and have left the mpg register going since I got it new.
It started around 52 in the beginning, and has steadily risen until presently at 7k miles it's at 55.2mpg.
California e10 gas, mostly under 2k elevation, mostly Santa Cruz Mtns twisties. I don't beat it, but I do ride it in an, erm, 'spirited' manner.
Sounds like most of the 45-50 mpg posts come from 15-16's.
I suspect the thing is probably running too lean, (Californis emissions), and wouldn't mind giving up a few mpg's for engine health.

[duhs10]

Something rarely mentioned in the MPG thread is WHAT YEAR THE BIKE IS. 15-16's are one thing, the 17 supposedly has different mapping. I have an off the shelf 17, and have left the mpg register going since I got it new.
It started around 52 in the beginning, and has steadily risen until presently at 7k miles it's at 55.2mpg.
California e10 gas, mostly under 2k elevation, mostly Santa Cruz Mtns twisties. I don't beat it, but I do ride it in an, erm, 'spirited' manner.
Sounds like most of the 45-50 mpg posts come from 15-16's.
I suspect the thing is probably running too lean, (Californis emissions), and wouldn't mind giving up a few mpg's for engine health.

I think you make a good assessment. I'm sure it's lean, almost all bikes come from the factory lean for emissions. I have a '15, average about 47 (akra exhaust, and ECU flashed), but when I take it to the mountains I often see 50 ot more.