GStwin.com GS500 Message Forum

Main Area => General GS500 Discussion => Topic started by: Jundie on June 16, 2004, 07:58:15 AM

Title: more hp??
Post by: Jundie on June 16, 2004, 07:58:15 AM
ok i found this on the internet and was wondering if the gs could profit from this.



f you own a bike with 10mm spark plugs, try NGK CR9EK spark plugs. (They come standard on the Yamaha R6 and the ZX9.) They're the ones with double electrodes. F2s, F3s, and F4s FZRs, ZX6s, 7s and GSXR's all use the single electrode type, and can be improved by switching.
   I've tested most every type of spark plug available. There are some "racing only" plugs that go for over $40 each !!

The NGK CR9EK or NGK CR10EK are the only ones I've ever seen make a power difference. They cost about $7.00 - $9.00 each. The gain is from 1 to 2 horsepower increase, depending on the condition of the plugs you're replacing. That's a huge money to power ratio!

The "9" or "10" number refers to the heat range, which also doesn't matter. (it really doesn't)

The "EK" refers to the fact that they have dual electrodes. There isn't any advantage to having 2 electrodes. Think about it: You can't beat physics and get 2 sparks at one time. (That's the "Splitfire Theory")

Why Do They Work Better ??
One reason the CR9EK's or CR10EK's make more power is because they take up more space in the combustion chamber, which increases the compression ratio. The second reason is that the spark is .040" / 1mm deeper into the combustion chamber. I think that increases the burning efficiency at high speeds.

They work so well that Yamaha uses installs them in the R6 from the factory.

One word of warning: they have to be replaced more often since the last thread of the plug extends into the combustion chamber. This means that as the thread on the plug gets loaded with carbon over time, it can damage the threads in the head on the way back out. If you don't want to change your plugs once a season, these aren't for you.


question one: do we have 10 mm sparkplugs?

question two: is this for real??? if so I will definetly try this
Title: more hp??
Post by: MarkusN on June 16, 2004, 08:04:04 AM
Nope the GS spark plug is M14

And I very much doubt that the "increased compression" effect is noticable in the GS.
Title: more hp??
Post by: Jundie on June 16, 2004, 08:16:11 AM
crap, well this closes the issue :(
Title: more hp??
Post by: fawndog on June 16, 2004, 09:34:58 AM
Quote from: MarkusNNope the GS spark plug is M14

And I very much doubt that the "increased compression" effect is noticable in the GS.

12 MM ?
Title: more hp??
Post by: scratch on June 16, 2004, 11:10:08 AM
I'd be more worried about gettin' my sparkplug gapped by the cylinder with a sparkplug 1mm deeper into the cylinder.
Title: You mean...
Post by: The Buddha on June 16, 2004, 11:22:27 AM
You mean piston Scratch... not cylinder...
Cool.
Srinath.
Title: more hp??
Post by: dgyver on June 16, 2004, 11:53:16 AM
Quote from: scratchI'd be more worried about gettin' my sparkplug gapped by the cylinder with a sparkplug 1mm deeper into the cylinder.

1mm deaper would not be a problem with stock pistons.
Title: more hp??
Post by: dgyver on June 16, 2004, 12:42:26 PM
Here is an interesting article on spark plug selection:

http://www.strappe.com/plugs.html
Title: more hp??
Post by: MarkusN on June 16, 2004, 11:54:46 PM
Quote from: fawndog
Quote from: MarkusNNope the GS spark plug is M14

And I very much doubt that the "increased compression" effect is noticable in the GS.
12 MM ?

You are right of course. My bad, I shoulda known better. ;)
Mixed that up with the oil drain plug question that we recently had. Anyway, it's not an M10, so no harm done. Phew!
Title: more hp??
Post by: Manix on June 17, 2004, 04:38:32 AM
Has anyone tried these (http://www.ngksparkplugs.com/products/cars_trucks_suvs/iridiumintro.asp?nav=11400&country=US) plugs? I've heard good reviews about them from fellow riders.
Title: more hp??
Post by: MarkusN on June 17, 2004, 06:16:22 AM
What I have heard is that they save you about as much money as they cost you. But it sure sounds good if you can say "I've got iridium plugs!"