positioning of spark plug nose.

[wornknobby]

Ok, so i had my jetting pretty close to being perfect(at least for my altitude,temp, etc..) and I just got the needle jet that i have been looking for for about a year.

but as i started to check my jetting again i came across this situation of when i pull the spark plug one half of the insulator nose and arm are actually "changing" to the light tan color

the other half looks untouched, like it looks when it is brand new.

This makes no sense at all b/c this has never hppened to me before, and i have used alot of plugs through my riding career. :blah:

would the position of the plug do this? maybe the side with the color is facing the exhaust port is the only one "receiving" :coocoo:

 

[Jaybird]

I noticed on my ktm125 that when I got very close to optimum on the main jet, the plug would also show the same sort of color pattern as you are describing.
I found that it wasn't a matter of how the strap was positioned in the jug, but rather just how the turbulance during combustion did things.
I marked different plugs and found that it was not in relationshop to the strap position.
I'm certain it is simply the charectoristics of the particular combustion chamber. My yz125 does not show this when the main is close to optimum.

I think your main concern should be on keeping a 1-2mm carbon ring at the base of the insulator and let the tip do what it does.