Picture of a healthy spark plug?

[Guest]

Search turned up nothing, as it won't let me use the term "pic." Just to assuage my fears.

[Can_O_Tuna]

Normal Condition:
click on image for full size view


The Spark plug to the left is what a normal plug should look like.
Grayish-tan to white in color indicates the plug is operating at the proper heat range as well as correct jetting and the cylinder is running healthy.
RACER TIP: That vertical color band on the ceramic shows you where the plug is indexed. Meaning that band is aimed slightly at the exhaust valve. Optimum location places the band HERE. If the band is anywhere but here, it means that when the plug is not at it's optimum location. There is still discussion as to whether indexing a plug is worthwhile, but on may applications looking for that last horsepower, it doesn't hurt.

[Can_O_Tuna]

Carbon Fouled:
click on image for full size view
This is very common visual condition on our race engines. Soft, black, sooty, dry-looking carbon. This indicates a rich mixture, weak ignition or wrong heat range plug (too cold).
You will first need to verify plug heat range. On carbureted engines, check choke as well as choke pull-off (if equipped) for proper function and adjustment. On fuel injected engines, check for clogged injectors and the cold-start valve and circuit. You also need to check for correct fuel pressure settings.
As a general rule on all computer-controlled engines, you need to also make sure that all input signals to the computer are working and accurate. This includes, but is not limited to, all temperature and pressure sensors as well as the EFI system components.
Lastly on all engines, check for vacuum leaks and weak spark or low voltage output. (Good reason for a better coil and aftermarket ignition unit "amplifier").

[Can_O_Tuna]

Worn Out Condition
click on image for full size view
Excessive electrode wear, misfire during acceleration and hard starting.
Simply put as in it's description, it's worn out ... it looks ok color wise, so replace it with same plug or at least compatible heat range. You've all heard the term " If it works, don't fix it". Don't look for flaws with this plug ... just blame yourself for not changing it sooner.

from http://www.centuryperformance.com/spark2.asp

[UncleMike]

Thanks much!


So now,...how to index,...

[Can_O_Tuna]

Thanks much!


So now,...how to index,...

*How bout getting it running right before squeezing every last HP out of it* edit..fogot italics er asteriks

:-D:-D

[UncleMike]

*How bout getting it running right before squeezing every last HP out of it* edit..fogot italics

:-D:-D

Fair enough.

(Jerk.)

[Can_O_Tuna]

Fair enough.

(Jerk.)

If you happen to get the plugs wet because of a no-start or whatever you can heat the electrode with a propane torch and pop 'em back in nice and toasty It will help it start a bit easier....I always do this with the lawnmower or snow blower for the first start of the year.

(off) lol

[KEITH KRAUSE]

Normal Condition:
click on image for full size view


The Spark plug to the left is what a normal plug should look like.
Grayish-tan to white in color indicates the plug is operating at the proper heat range as well as correct jetting and the cylinder is running healthy.

Not trying to be picky here. That plug looks OK. It's hard to get a good picture of a plug. But, the correct color range description isn't true. "Grayish-tan" is OK, but "to WHITE" is too lean.

[halvorja]

Here's an image that I have scanned from an automotive manual. In my opinion, the plug that is considered "normal" isn't quite normal for our motorcycles; however, these images give you an idea of the different types of plug conditions you may see in your life. The descriptions are nice.



Jake

[quakeholio]

I've heard that NGK's are a bit on the hard side to do plug reads on, but Chamipon work pretty well. Just make sure you swap back when you are done.

[flyingace]

I'm not sure GS plugs need to be 'tan' to indicate proper running. My bike is box stock and runs great - idles fine, accelerates well and has power throughout. It doesn't ping or surge or anything else indicating a lean mixture. The plugs are all far more white than tan, but I don't see the point of trying to 'fix' the plug color.

[rustybronco]

How about this.

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

[flyingace]

My plugs are whiter than any shown here on this chart, but display none of the damage you can see associated with pre-ignition. The closest I see are in the hot/lean but OK range.

[relic-rider]

I agree with the hot/ lean ? kinda white plug being ok. After rebuilding my carbs, my plugs were white and my pipes were starting to discolor yellow. It was real doggy in the mid range also. I found the floats were set wrong, so I redid it and shimmed my needles a little. Pipes are good now, throttle is good all the way through now, but he plugs are still white and pretty clean. I'm not going to worry as everything is going good with no excess heat. I did check my plug boots and they were junk. 3 at 10K ohms and one at 30K ohms. I replaced them today. Will see if anything changes.