spark plug pics

u are part right, it still effects overall temp as the heat from the plugs transfers to the cylinder head as ilistrated in the link and in gordon jennings book.

so i went to get a new spark plug but all they had was the standard ngk and u wanted to upgrade, but on the was home my bike started sputtering and backfiring on me. the same thing happend last night. it was running better than ever befor with the new jetting. when i pulled the plug there was a carbon bridge fouling out the electrode. im gana check to see if it did it again. i'm pretty sure because the exact same symptoms. but what would cause the carbon bridge. it is still the #6 plug so it should burn hot enough to keep it clean. i was thinking maybe it is cleaning some of the carbon off the piston than sticking to the electode. does anyone have an opinion on the matter?

It could be 3 things.
1. Spark plug is too cold.
2. Too much oil in the fuel mix.
3. Carb is tuned extremely too rich.

Lucas semi- synthetic mixed at 50:1 is the recommended ratio as suggested by Lucas, so you are good there; rules our #2
The engine running better after you enlarged the main jet rules out #3.

That leaves #1 to contend with.

im running oil called blue marble. it his high proformence and doesnt smoke but is not synthetic. i get it from a local small engine repair shop. im running 3oz to a gallon. i plan on switching to ams oil but i had bought a gallon of the blue marble. maybe i should try 2.5oz how do u know if u need more oil without seazing

Sorry, I read what the OP was using and it is Lucas. I confused the issue there.
I looked up Blue Marble to read up on it.

3.0 oz oil to 1 gallon is higher than a 40:1 ratio. very little oil there.
2.5 would be even less. I do not recommend trying it.

I do not know of any trick to "read" the lubrication needs of a running 2 stroke engine other than if it seized it got too hot or needed more oil. That is a horrible way to diagnose things!
I can only suggest that you run 32:1 and know that adequate oil is being provided.
4 oz of oil to 1 gallon of gas. It has never failed me in my 25 years of riding and tuning 2-strokes.

Get a hotter spark plug so it will keep itself clean before lowering the available oil that the engine relies upon for lubrication.

Here is an interesting read to confuse things a little bit:
http://www.dansmc.com/2stroke_oil.htm

i have to agree with u. a seazed motor is not the way i want to find out. i use a drink measuring cup and because oil likes to stick to the plastic i always go a little more than 3oz but the next mark is 4 and it is less than that. but i have cleaned the head and piston a few times and there isn't realy any sings of wear, im a machinist by trade so i would notice it. so i think im gana clean the head and piston again befor going to a hotter plug just to make sure that the better combution was not burning the carbon off that has built up and pieces are sticking to the plug. if it still does it i will be switching to the #5. i have a little over 1k miles and this just started. i will give an up date just to help others. and thanks for the assistance.

ok I have a problem with a jerky feeling when running doesn't matter what speed or throttle but it is constantly here any ides????

Engine is not completely broken in?
Drive chain too tight?
Wheel bearings need servicing/ bearing pre load set too tight?
If your rear wheel has one of the Chinese knockoff coaster brake hubs the brake shoes could be dragging.

Carburetor float height set too low?
Bad electrical connection between the mag and CDI?