Spark plug color question
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Road Master
Joined: Apr 2014
Posts: 841
Likes: 58
From: Yakima
Spark plug color question
Decided to check my spark plugs today. Bike has about 5k mikes on it. Each plug has a diffrent color. Just wanted to get your guys opinion on it.
Photo attached. Left pic is from front cylinder. Right pic is from the rear cylinder. Looks like the rear plug is a little darker.
Photo attached. Left pic is from front cylinder. Right pic is from the rear cylinder. Looks like the rear plug is a little darker.
Cruiser
Joined: Mar 2014
Posts: 125
Likes: 0
From: michigan
You're burning rich, but that is better than lean. The old tan color or brownish color doesn't fit any more nowadays because there is no lead in the gas. look down in the plug at the porcelin...it's hard to tell from the pic, but looks like your porcelin is black almost all the way up to the threads...that means your main is really rich. Heat range looks good. Hard to tell about the low and midrange b/c it looks like the plugs have been run a good while, but it looks a little rich there too b/c the porcelin is black up to the electrode on the plug in the left pic. I assume the left plug is the rear cylinder?
MODERATOR
Joined: Oct 2007
Posts: 4,108
Likes: 1,964
From: New England
Late model EFI bikes are notorious for giving "false" plug readings.
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Micheletti
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May 4, 2009 10:49 AM
