Spark plugs

OldCroc

OldCroc

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My bike has been a bit rough on idle so I decided to pull the plugs and have a look. I have noted that the primary is a nice grey colour but the secondary is blackish with a little oil on the threads.
I put a Draper spark tester on the secondary and seems like the coil is fine as there was good spark. Is it normal for the plugs to be different colours? ( I have only done one side so far - thought I would get some advice before doing the other)
Will try and stick a photo on here.
2bef1e336b5e0bc1ba91aa536215bc74.jpg



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Both don't look stellar by any means.

Ideally the plug should be a light chocolaty brown, with small deposits on the porcelain.

what do the plugs look like around the internal of the electrodes?

Are the electrodes uniform, not arced away or sooty deposits over the porcelain?

I can understand the lower plug being slightly oily sitting on the lower of the combustion chamber, where oil will naturally accumulate.

How old are the plugs?

Did you do a proper old fashioned plug chop? (does that work for 4 strokes?)

or is this an as is plug removal?

BTW where are the other 2?
 
My experience is, Lower plug; a darker brown insulator than the central plug and showing a bit sootier around.
Mine is usually like that and i get good fuel consumption and economy so it can't be running bad.
Give them a clean up, gap them and stick them back in :thumb2
 
I'm afraid the days of trying to monitor how an engine is running by looking at the plugs are long gone.
 
UturnTony said:
My experience is, Lower plug; a darker brown insulator than the central plug and showing a bit sootier around.
Mine is usually like that and i get good fuel consumption and economy so it can't be running bad.
Give them a clean up, gap them and stick them back in :thumb2
Click to expand...
Don't gap them. When they wear out replace them. Would be better to show a photo into the end of the plug.
 
OldCroc said:
My bike has been a bit rough on idle so I decided to pull the plugs and have a look. I have noted that the primary is a nice grey colour but the secondary is blackish with a little oil on the threads.
I put a Draper spark tester on the secondary and seems like the coil is fine as there was good spark. Is it normal for the plugs to be different colours? ( I have only done one side so far - thought I would get some advice before doing the other)
Will try and stick a photo on here.
2bef1e336b5e0bc1ba91aa536215bc74.jpg



Sent from my iPhone using Tapatalk
Click to expand...

They look OK, it's normal for the bottom plug to be darker and oily.
 
Here's a picture for reference.
Just took these out of my TC GSA.
They've done just over 29k miles. Bike is remapped and runs well.
Left to right:
Secondary (lower), primary, brand new.

The primary ones have eroded away, but it still ran well!
5b550f86bb4c3c16653595f81a5ac648.jpg


Sent from my GT-I9505 using Tapatalk
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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