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I notice the front plug on my 2011 EG ultra classic doesn't burn as well as the other..it's always darker. I can't really tell if it there's a miss, but one plug and 1 exhaust is darker than the other. Any ideas??
 

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The front cylinder runs a little cooler than the rear as it gets relatively cleaner air flow. The air to the rear cylinder is blocked and heated by the front cylinder. There may be just enough difference to make the front plug not hot enough for the anti fouling additives in your fuel work their best.

Do you have an after market tune of fuel modifier? A weeping front fuel injector may be making the front cylinder run just a bit richer than the rear. A spark plug wire not fully seated on the plug or in the coil might cause an occasional misfire or poor spark/poor combustion. Check for codes, front cylinder miss, front cylinder rich etc.

Swap the plugs and see if in 1000 miles or so, the rear plug (now in the front cylinder) is doing the same thing the other plug did when it was in the front. If it does, the spark plug is not at fault. If your fuel economy is unchanged and it starts easily and runs well this probably isn't worth worrying about.
 
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