Read my plug....

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Onder

Onder

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I'd appreciate some comments on reading this plug. It is two views of the same plug.
Two hours plus of 2500-3500 rpm riding mostly at about quarter throttle on the lanes.
 

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Is this a trick question test? ;)

If it doesn't stumble anywhere, I'd be happy with those plugs. Mine never look better on a motor with 8K not so gentle miles on it. I don't have valve guide seals, so I'm burning little oil, and am slightly rich off idle with accelerator pump carburetion. That's what I attribute to the similar fuzzy black ring I see on mine. If I just blip the throttle in the driveway for 10 or 15 minutes, my plugs are darker everywhere. If I get it out and ride it, they look like yours upon return. I'm happy with how my motor runs. Not sure that means much, but it is as it is.
 
Plug seems too black to me around the rim. You point may be correct that out on the road it will be clean. This isnt a plug chop.
 
Well, I’d say that outer ring is a bit on the black side personally. Whether that’s richness or oil I dunno. Hardly anything to panic about, but you did ask...
 
Is there signs of insulator deterioration, like from excess temp?
 
Schwany said:
Is this a trick question test? ;)

If it doesn't stumble anywhere, I'd be happy with those plugs. Mine never look better on a motor with 8K not so gentle miles on it. I don't have valve guide seals, so I'm burning little oil, and am slightly rich off idle with accelerator pump carburetion. That's what I attribute to the similar fuzzy black ring I see on mine. If I just blip the throttle in the driveway for 10 or 15 minutes, my plugs are darker everywhere. If I get it out and ride it, they look like yours upon return. I'm happy with how my motor runs. Not sure that means much, but it is as it is.
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Doing that will tell you nothing, (bliping the throttle for 10-15 mins) except p*ss off your neighbours - if you have any.
Only riding at a constant speed up a light incline before doing a plug chop (if you know what one of them is) .... then taking your spark plug reading will give you information of any value.
Whoops, just reread the post, I'm talking to the wrong person...soz.
 
Info needed - is it possible to glean any info from a spark plug by doing a ‘plug chop’ these days with the gnats-piss sold as petrol?
 
Tornado said:
Is there signs of insulator deterioration, like from excess temp?
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I noticed that too. But it looks more like a deposit rather than overheating maybe.

I think I got ok at reading plugs but they were new plugs using race gas in race conditions.

Under street riding conditions it's kind of impossible to learn anything other than really obvious over heating or oil and too rich.

If anything I'd say a bit black on the rim but in contrast the insulator may be a bit distressed from heat or just old ??
 
I would rather see a little less black around the rim but that doesn't really bother me. I would like to see the ground electrode at least a little more tan but that really doesn't bother me either. I don't like the look of the center electrode insulator. What brand/number are these? Does your gas have ethanol? They certainly look good enough to use.
 
marshg246 said:
I would rather see a little less black around the rim but that doesn't really bother me. I would like to see the ground electrode at least a little more tan but that really doesn't bother me either. I don't like the look of the center electrode insulator. What brand/number are these? Does your gas have ethanol? They certainly look good enough to use.
Click to expand...
Judging by the centre electrode, the ignition timing might be out, or is that the burnt gas covering it up?
 
Correct timing is shown by a color change on the ground strap right at the bend. It's a little hard to see on those pics but I think I can make it out. I also don't see any black flecks on the insulator that would indicate detonation. As other's have mentioned just a tad rich shown by the full ring of black on base of threads. Ideal would be a 1/2 turn or so. I would not change the jetting though as the plug is no where close to fouling out.
 
Unleaded fuel does not color plugs (unless it is way-to-hell-and-gone off the map TOO RICH) like the all the repair manuals show. Unless you are running leaded RACING fuel, and running that engine HARD (like racing conditions) trying to tune by sparkplug coloration is jousting at windmills.
 
The crust on the insulator looks like residue from petrol that must be different from mine, or an additive.

The black on the rim may indicate a rich-ish idle mixture, but maybe your bike needs that.
 
This is the less happy cylinder. The other looks less black, much cleaner. I should really do a compression check.
And you have a good point about what it wants and what it is supposed to have regarding idle air adjustment and
perhaps needle position.
 
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