Spark plug threads

Normal. Even my lower compression two strokes do it.


Use a small amount of "Never Seize" lubricant to the threads of the plug to avoid a costly repair and more importantly down time! 2001 YZ426F 1996XSR650L

I am wondering if anyone has had this exerience, and if it is normal.

When removing the plug from my 01 426, the last three or so threads are always dirty. By dirty, I mean its as if you used a plug with too long of reach. Its as if the last three threads are in the combustion chamber and small amounts of carbon are deposited on them. After the plug has been in a while, this makes the removal of the plug harder, and you cannot turn the plug wrench by hand alone.

I want to explain that the plug looks great and the insulator is a perfect tan color. I just fear that the the deposits on the last three threads could damage the threads on the head during removal.

Is this common? Should I worry? Are the last three threads on your plugs dirty?

I should say, before anyone asks the question, that I do use the correct plug.

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