Plug Fouling in KX80. help

Seems like it would be fine to me. The reason it doesnt work with the other one is probably a jetting thing or that maybe your not riding it hard enough.

punksthree--

I have a KX100 which also calls for the NGK105. The reason you are fouling it is because it's a "cold" plug. By cold I mean doesn't give off as hot of a spark as the BR8ES, and that's why you foul the 105 and not the 8. When looking at spark plug codes (R626K105, BR8ES, BR9ES, etc.), the number in the code tells you the intensity of the spark. The lower the number, the hotter the spark and the more resistance to fouling. In the NGK105's case, the "105" actually means 10.5 which is an extremely cold plug. You'll also get better lowend power with a hotter plug. Hope this helps.---dirtfreak

P.S.--The BR8ES is actually the hotter alternative to the cold stock plug so yes, it's safe to run.---dirtfreak

We had the same experience with my son's 02 KX85. The plug the factory recommends just plain doesn't fire hot enough to keep from fouling the plug. Often times he'd foul a plug just sitting on the starting line. Switched to NGK B8ES or the Champion equivalent N2C, and went three months before changing the plug. Actually had better results with the Champion and they were $1.25 each at the local Auto Zone.