Wath can I do to change the color of spark plug

[adriano.ro]

Bike: ec 300 2008 jetting:42,N3CG@4 ,180 main. temp: around 20c-27c. Motorex crosspower 50:1.
Bike runs good,start very good,idle good.all ways looks like that.
Lean or rich? Looks lean to me but with this settings I'm not so shore.

 

[(F5)]

Ignore it, you are not learning anything from that picture.

It is well conceivable that an engine could be rich on closed throttle, lean on 1/2 throttle, and rich again on open. Reading a plug in an uncontrolled experiment will draw no reliable information.

Long straight, wide open for long time, pull clutch, kill engine. That will give a clue about the main, but otherwise forget just looking at the plug. Really most useful for road racing.

 

[barossi73]

The outer electrode should show a colour change in the middle 2/3 if heat range is correct,a plug with more hours on it gives an overall indicator and also colours quicker if you have made a jetting change.also some oils skew the colour.should be a fine white ring on perimeter of center electrode face if ignition correct.deep down the ceramic core should be a discoloured ring,not white/grey (hard to see without cutting threads off)
Otherwise it varies as stated above depending on your last ride.