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Discussion Starter · #1 ·
Does anyone know how the different plugs would affect performance, idling, etc. As you know there are 2 plugs recommended for the Grom...one is for normal riding and the second is for high speed riding. I definitely need the latter and in fact, have replaced the standard with it, but I can't say I've noticed any difference. Other than the plug firing from a smaller area of the plug, what is the difference?
 

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The "high speed riding" plug is actually going to run cooler than the standard plug, by transferring more heat to the cylinder head. Because of this, it may build up deposits and foul sooner than the hotter plug, if it's used on a bike that is not run at higher speeds, for longer periods of time. On the other side of the coin, if you run too hot of a plug (say, a standard plug on bike that is ridden at high speeds, a lot), then your chances of pre-ignition increase.
 

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Do you think it would foul a plug even with fuel injection?
 

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Have you done a plug check lately? She's running pretty lean off the assembly line.

If it fouls the plug, so what. Pop a hotter plug in there and keep rolling.
I personally have my Grom topped out in canyon riding for 45mi, each way, trips.

I'm experimenting with the E3 plug that the high speed plug cross references to. Always felt they were snake oil but I'd rather buy one plug to play with rather than screw with my STI's state of tune.
 

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If you're concerned about fouling, but want to run with the cooler plug, you could switch to the iridium version of the NGK plug (CPR7EAIX-9, instead of CPR7EA-9).
 
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Discussion Starter · #6 ·
When I replaced the standard plug with the fast riding plug at 600 miles, the standard plug looked fine.
 

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My plug looked that way @ 300 miles. I think the ecu looks to keep the same AFR as much as it can. But the AFR target is too lean anyway. Or something.
 

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Would adding a CPR8E or CPR9E to my setup now that I added intake/exhuast/tuner help with heat?

I currently have CPR7E installed.
 

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I've tried all these plugs

CPR7EA-9 the grom runs ok with this plug
CPR8EA, this plug is ok
CR8EIX-4218 this runs great WOT

I will test the CR9EIX-3521 today

The difference between the EIX plug and the CPRxEA plugs is the tip is very narrow and does not stick out as far as the standard plug plus the price is like $10 vers $4

 

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Farkas gave me some information about running the ngk cpr8ea-9 plug with my current mods.

125cc stock bore, EFIE device, stock intake mod, tyga exhaust full system, 91 octane, always running the bike in the 6-8k rpm range.

I was just wondering if anyone notice a difference or had any experience with the ngk cpr8ea-9 plug with a slightly modified bike.
 

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I've tried all these plugs

CPR7EA-9 the grom runs ok with this plug
CPR8EA, this plug is ok
CR8EIX-4218 this runs great WOT

I will test the CR9EIX-3521 today

The difference between the EIX plug and the CPRxEA plugs is the tip is very narrow and does not stick out as far as the standard plug plus the price is like $10 vers $4
If anything the platinum tips should perform marginally worse than the "standard" plug as platinum isn't as conductive as a "standard" shielded copper plug. The selling point on platinum plugs is the longevity in plug life.. that's literally it.


Farkas gave me some information about running the ngk cpr8ea-9 plug with my current mods.

125cc stock bore, EFIE device, stock intake mod, tyga exhaust full system, 91 octane, always running the bike in the 6-8k rpm range.

I was just wondering if anyone notice a difference or had any experience with the ngk cpr8ea-9 plug with a slightly modified bike.
You likely won't notice the difference unless the bike is detonating really bad, or the spark plug is simply too "cold." Unfortunately a lot of things determine what spark plugs someone should consider, and there really isn't a one-plug-fits-all scenario, which is why you have to keep an eye on the condition of your plugs on occasion.

BTW, your inbox is full :)
 

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If anything the platinum tips should perform marginally worse than the "standard" plug as platinum isn't as conductive as a "standard" shielded copper plug. The selling point on platinum plugs is the longevity in plug life.. that's literally it.




You likely won't notice the difference unless the bike is detonating really bad, or the spark plug is simply too "cold." Unfortunately a lot of things determine what spark plugs someone should consider, and there really isn't a one-plug-fits-all scenario, which is why you have to keep an eye on the condition of your plugs on occasion.

BTW, your inbox is full :)
Farkas,

I sent you a PM. But I might as well post through here for others to see.

My bike actually ran a lot worse with the CPR8EA-9 plug with the mods I have. Power surge after I let off gas, loss of power. Lower top speed. I'm still using 91 octane fuel.

Here are some pictures after about a 30+ mile ride.

Spark plug Auto part Automotive ignition part Automotive engine part Spark plug Automotive ignition part Auto part Automotive engine part

Brown/copper ground. Ring is turing lighter.

Let me know what you think
 

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Farkas,

I sent you a PM. But I might as well post through here for others to see.

My bike actually ran a lot worse with the CPR8EA-9 plug with the mods I have. Power surge after I let off gas, loss of power. Lower top speed. I'm still using 91 octane fuel.

Here are some pictures after about a 30+ mile ride.

View attachment 29505 View attachment 29513

Brown/copper ground. Ring is turing lighter.

Let me know what you think
So far it's looking a little too cool according to the very narrow color at the tip of the strap and little color on the threads. Curious, what do you have your EFIE unit set to right now? None of that would really explain a surge after letting off the gas, though.
 

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So far it's looking a little too cool according to the very narrow color at the tip of the strap and little color on the threads. Curious, what do you have your EFIE unit set to right now? None of that would really explain a surge after letting off the gas, though.
The EFIE set to 250mv. 80-100% throttle everywhere. Since my bike is stock bore, maybe the plug is too cold for stock bore.
 

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The EFIE set to 250mv. 80-100% throttle everywhere. Since my bike is stock bore, maybe the plug is too cold for stock bore.
You might even consider 200mv with the EFIE as some found 250 and 225 with a cam and other mods to be a bit too rich.
 
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