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Discussion Starter #1
Quick question,

The manual calls for NKG CR9EK plugs, last time I was at the shop I must have missed it but they gave me CR9E. Is there much of a differance there?? Could I still use them or should I go back and exchange them??
 

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It's more work to do the job and then have to change it than it is to just go back to the shop. :)

Why are you replacing the plugs already?
 

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Discussion Starter #3
Binary Jay said:
Why are you replacing the plugs already?
Probably cause I'm gettin close to 26k miles already. Last time they were changed was 16-17k.
 

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Wow, that's crazy. I just had the same thing happen to me yesterday. Got the right plugs today. I wonder if they've got a bad book out there somewhere...

Anyway, I figured I'd just stick with the recommended ones. The obvious difference is that the CR9E plugs only have one electrode, where the CR9EK have two. I doubt the extra electrode does any good, but who knows what other differences there might be? Do plugs even have temperature ranges these days?
 

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Excerpt from the NGK site.

SPARK PLUG BASICS:
The spark plug has two primary functions:
  • To ignite the air/fuel mixture
  • To remove heat from the combustion chamber
Spark plugs transmit electrical energy that turns fuel into working energy. A sufficient amount of voltage must be supplied by the ignition system to cause it to spark across the spark plug's gap. This is called "Electrical Performance."

The temperature of the spark plug's firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called "Thermal Performance", and is determined by the heat range selected.

It is important to remember that spark plugs do not create heat, they can only remove heat. The spark plug works as a heat exchanger by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling system. The heat range is defined as a plug's ability to dissipate heat.

The rate of heat transfer is determined by:
  • The insulator nose length
  • Gas volume around the insulator nose
  • The materials/construction of the center electrode and porcelain insulator
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Summary:

Since the EKs are longer than the E's, approx. 2mm longer. It has better heat exchange characteristic. The gas volume also will change since the E is shorter. The EK's also have double electrodes for better spark spread.

I'd say change it back to the specified CR9EK plug. You might regain about a horse or 2 that you lost changing it to the E.
 

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Discussion Starter #6
Well it looks like I'll just wait on changin them then. I won't be able to get new ones till Monday though since I'm goin to PA friday and comin back Saturday. The bike should be fine till then, I'm not that far over the recommended change miles.
 

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I'm guessing that you could probably go nearly twice as far before anything actually fails.

Not that anybody would recommend that.
 

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Mark_FZ6 said:
Wow 26k miles does it still pull like it used to I hope mine last that long.
Me too...I just passed 16k last weekend and I'm preparing to haul it in for the 16k service (repacking the swingarm bearings...something I don't think I can handle, lol) before striking off on my NC road trip next weekend.
 
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