What part of the plug do you read to evaluate air/fuel mixure?
I just pulled my plug. The insulator is white. The electrode is gray. And the base is black.
Craig

 

That's normal. With unleaded fuels today and better ignitions, it's nearly impossible to make finite jetting settings based on plug appearance like the old days.

 

True that, with all the ethanol and additives it is not like it used to be.

 

(Running just a slight tick rich on either primaries or mains--black carbon outer ring, although heat range is probably about right since you're getting thorough combustion, no deposit on insulator--good. I would guess either your primaries or mains are a smidge too big, because it looks like a "1/2-rich" condition where one or the other is slightly rich, but the other one is correct so it burns off. You're still within normal limits; nothing to really worry about--agree with TNC^.)
My two cents....

 

Spark Plug Colour Condition for Carburetor Tuning Guide

 

That's a great guide for the way jetting and plug readings "used to be". I haven't seen plug colors like some of those optimum readings in many, many years. It has to be our fuel IMO that's the biggest contributor to why plugs look so clean and white now. Emission requirements have driven the combustion process to be super clean, even on our simple, carburetor equipped bikes.