Iridium spark plugs in a redhead?


I use the NGK iridiums. The SX's don't seem to foul plugs too much as it is, but I like the extra insurance and they always seem to start right up.
 
Well I bought set of the Denso IW27 $28.00 on e.bay..I just took the SX700 out of storage couple weeks ago ran it 10min. or so and it's been sitting since, the fuel, carbs and engine were loaded with ATF and a dose of marine Stabil..once I work that thru I'll switch out the copper NGK's from last year with these IW27's and report back.

My SX700 (4,700mi.) ran flawless last year other than the 3-6k burble, even that was hardly a problem beyond the sound..these engines sound so sweet I'd like to have it perfect..maybe this might help..the other reed spacer mod looks like it may have been installed by the previous owner.
 

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I tried the e3 plugs last year and can 100% say that they improved starting and it seemed to run crisper.
 
I honestly just stick with what Yamaha recommends, there is a reason they picked the BR9Es (make sure they are the Solid type). Ive never had a problem with any of my sleds, and obviously your sled has been good running on the coppers? Ive experimented in the past with my cars and sleds and quads and honestly I think most fancy plugs designs out there today are just gimmicks. (E3, the double/triple/four prong, iridium)

I might use platinum plugs in something that has a fouling issue to increase life. (But if your fouling plugs its usually a sign of a problem that should be fixed)
The only difference between platinum and iridium (for properties which matter to spark plugs) is a slightly higher melting point, but at 1800 degrees I think your aluminum block would melt before your platinum plugs did.

The other reason I dont use iridium plugs in a sled is that iridium (especially at lower temps) is very brittle compared to platinum or copper, the iridium sometimes will tend to flake or chunk off. Instead of paying for iridium plugs I just change my plugs every season and always have 2 sets of new spares with me.
 
Until recently, platinum was considered the best material to use on the top of an electrode because of its durability. However, Iridium is 6 times harder, 8 times stronger, and has a melting point 1200 degrees higher than platinum. Put that into a harsh environment such as an engine piston chamber, and you have a spark plug that can resist wear much better than platinum. Additionally, the DENSO Iridium Power alloy is so durable; it allowed our engineers to produce the world?s smallest center electrode (.4mm) which reduces the voltage requirements, concentrating its sparking power. Also, its smaller size, combined with the tapered U-Groove ground electrode, allows more room for the flame kernel to develop and produce a more efficient combustion.

Generally, you do not purchase spark plugs for performance enhancement. While DENSO Iridium Power spark plugs have contributed to numerous accomplishments through dyno-testing and actual use, their true benefit lies in their efficiency, durability, and improved firing power. Serious tuners modify their vehicles by increasing boost through turbo-chargers, super-chargers, and Nitrous. They are also known to add high-energy ignition systems, tinker with timing, adjust fuel mixture ratios, and increase horsepower through other means. Putting these kinds of demands on their engine increases the need for an efficient, durable spark plug that can handle these kind of harsh environments. That?s where DENSO Iridium Power can make a major difference.
 
1200 f yes, but even copper is well beyond the temp of any engine. A sled engine might hit a couple hundred degrees, hardness has no relevance, 8 times stronger in what matter? Ductility? shear strength? impact strength? brittleness? I can state stuff pulled from DENSO's literature too, and I can make dyno sheets as well (all the cold air kit companies do since most rob horsepower)

If your running a direct injection, high psi turbo, or nitrous ok...but on a sled (your not going to get anymore efficient)
When someone gives me solid proof that its either going to make more power or make my engine more reliable, then Ill switch, but I havent seen any sign of that.
Ill stick with my $3.00 BR9ES, I still have yet to foul one, just keep my carbs clean and run good fuel. I know everyone has their opinions, but people complain about the price difference to run premium fuel (which WILL make your sled run better, smoother, cleaner and help it last longer), but they spend an extra 15 bucks on plugs that do nothing...lol just makes me laugh

If your fouling plugs, clean your carbs, run good fuel and oil and keep everything tuned correctly.
 
I run BR9ES in all my sleds and two pulls even at -20*c, yamaha did change the newer sleds, but higher power requirments were needed for upgraded headlight and other upgrades. If you want to help cold start on a red head dont use your key or kill switch, kill the sled with the choke. This will also work for hot starts, do that and she'll start back up like a dream.

Or just cracking the throttle a bit when starting.
 
I do crack the throttle and half pull on a hot engine...Full or 1/2 choke to kill? do you always kill that way?
 
My friend had the same starting issue on his 99' our local Yamaha dealer told him to do this, he uses full choke. We both do it every time we ride it (he keeps it on my property) or as long as we remember to do it, hard to get out of the key/killswitch habit
 
thanks for the links..here's a pic..original? caps just unscrew? clip wire and install replacement?
 

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