reading a plug with nothing to read

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reading a plug with nothing to read

Postby xrongor » Sat Aug 25, 2007 1:47 pm

im getting plug chops that i cant read. the plug is pretty much just coming out clean. theres no specs on the porcelin to indicate detonation. ive tried a larger jet and that makes it 4 stroke badly. i plugged the holes in my airbox with the original jet and it 4 strokes. so the next thing that comes to mind is heat. ive gone two steps lower in the heat range and i get a little more color on the plug but not much. i've tried higher octane gas and that noticeibly hurts performance, and has no effect on my ability to read the plug.

ive cut the metal away to read the bottom of the porcelin and theres a small dark ring at the base and thats the best im getting. the best info i can find says this means im not running too lean.

the plug i just took out had about 700 miles on it and was just generally black, but not oily or cakey.

best guess at this point is that im running hot, but not lean.

so... ive got almost 2000 miles on the bike that way. it hasnt blown up, broken down, or caused me problems in any way. the plug is basically clean, but ive looked at it with a magnifying glass and i see no signs of melting or overheating. after 2000ish miles there is very little carbon build up. the top if my piston is smooth as is the combustion chamber so there appears to be no detonation. the rings are fine, everything is fine.

should i just leave it alone? how do you read a plug you cant read?

randy
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re: reading a plug with nothing to read

Postby Smitty » Sat Aug 25, 2007 2:01 pm

Is it possible that your timing is a tad too far advanced? I know that if timing is too far advanced then it will run the engine hot as well.
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re: reading a plug with nothing to read

Postby TowerTower » Sat Aug 25, 2007 2:04 pm

Randy,
The lack of colour is not as unusual as you may think. Under certain circumstances it is normal: in the sense that your engine will not deteriorate and the performance is optimized.

Fully synthetic oil at a 50:1 ratio with a hot plug operated mostly at WOT will almost always give this result.

Remember we are assuming that white = excessive heat (enough to burn off oil and gasoline residue). Well, consider what happens if there is much less residue to burn (fully synthetic oil has that property) or that the heat range is high yet tolerable (within 100o of optimal) (i.e. mostly operated at WOT), and that the plug actually performs better at this temperature (hot plug).

Only modern oils provide this ability, so I'd worry only if I were using non-synth oil.

(I do recall reading an article on this phenomenon sometime back, just can't remember where)

BTW, my Arrow is in the same situation: 1000 KM, all on a white plug.
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re: reading a plug with nothing to read

Postby xrongor » Sat Aug 25, 2007 3:31 pm

hey smitty its a cdi unit so theres not much adjustment. i did bump compression when i went to a 60, but not horribly much. i swapped the cdi's on my two bikes but that didnt change anything. thats one of the reasons i was posting about the PW50 cdi box earlier too, just to try it out.

yeah tower, im running synth at 50:1. ive probably seen the same sites you have that mention to cut the plug and check for that dark ring at the bottom of the porcelan . but otherwise suggest that when running synth that its perfectly normal to get a clean plug for exactly the reasons you mention.

ok. i just wont worry much about it for now. i just wanted to run this past the group.

thx
randy
"In this world there's two kinds of people... Those with loaded guns, and those who dig." -- Blondie to Tuco
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re: reading a plug with nothing to read

Postby xrongor » Sat Aug 25, 2007 5:17 pm

heres the plug with 700 miles on it. any flecks are just left over from the hacksaw job. the color on the tip of the porcelan was consistant with what you see on the right side before i rubbed it a bit to see how easy it came off. it would be pointless to take a pic of my current plug because there is nothing to see. only got 25 or so miles on it and it looks like it came out of the box.
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re: reading a plug with nothing to read

Postby Smitty » Sat Aug 25, 2007 7:06 pm

That's cool that you cut away the side of the plug like that so we can see the "full" plug reading. Thanks for that! It looks like a good plug reading to me.
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