There are no dumb questions.

The color should be even around the base ring. My intent was to convey that when you are jetted correctly, the base ring will be a soot color in a 360* arc (minus the diameter of the strap, of course). If you wanted to go a little leaner, (7/8 of the way around the base ring, or 315*) you would look for the soot color on the base ring to extend 315* around.

I've never noticed a color difference from one side of the base ring to the other based on the way the plug was indexed, be it towards the intake valve or otherwise.

 

Not in my book. The top one indicates you're in a preignition zone; that is the combustion temps are so high that ignition will occur anytime during the four stroke cycle....not good...it usually means broken pistons, rods, and crank at worst...destroyed bearings at best.

The middle one...once again, without a 5x magnifier, I wouldn't say either way, unless it was a lo-performance passenger vehicle, in which case it's okay.

The last pic....whew! Oil fouled bad. No magnifier needed for that one.

 

one more good article
http://www.off-road.com/dirtbike/tech/2002sparkplug/

 

I dont know bout you guys
but I"ve learned more bout reading plugs
in the last 8 hours, than I have my whole 40 years
n2 you ARE the man

 

I'll second N2 for the "MAN" award.

 

...so does that mean I get a Bozo button, or a Happy Meal? [img]i/expressions/face-icon-small-wink.gif[/img]

Glad I could help.....I've got alot of help on this and other boards, myself; I'm an ATV rookie.

Steve

 

In2xlr8ing:

Nice chart. How does the 2 stroke compare to the 4 stroke characteristics you speak of?. We always look at the ceramic to be a cardboard color brown with a small "crown" of white crystal in the electrode in the 2 stroke engines. What are your thoughts??

 

I would not be even remotely qualified to speak about 2-stroke engines. I can barely tell you how they work [img]i/expressions/face-icon-small-happy.gif[/img].

If I were a guessing man (which I am not), I would imagine that depending on the fuel you used, the technique would be the same. I've used everything from C16 to 93 to methanol (my current fuel of choice for my lil' turbo car), and I've always used the plug's base ring for jetting. I wouldn't feel terribly safe using strictly the porcelain....but as I stated, I know jack about 2-strokes...except that I got spanked by a Kawi triple once....[img]i/expressions/face-icon-small-smile.gif[/img]

 

Thanks, you probably are right. I never heard of anybody using the base ring for checking jetting on a 2 stroke. One of the key indicaters we use is piston wash on the piston head. This is inspected by looking through the plug hole with a mechanices probe lite.

Thanks for the info on the 4 bangers!!