Re: SO CAL orange county spark plug heat range-NGK
i gap mine at 25. i've experimented with gaps ranging from too small to start to too wide to run, and 25 seems to be the best.
honestly, though, i didnt feel much difference between 20 and 30. these motors aren't tuned well enough to take advantage of very small changes in gaps.
i agree with fat daddy. change the plug wire, crimp, and boot. that's about another 3-4 bucks.
7mm copper core, non-resistor wire works best.
the old wire just unscrews from the cdi. it may be glued in, then it'll break off when you twist it out, and you'll have to dig out the rest (carefully) with a small pick, then screw the new one in.