Spark Plug Cap Resistor

[Dave102429]

On a 2002 400EX, there's a 5K resistor inside the spark plug cap/boot behind the terminal that the end of the spark plug snaps in. Back when I had my XR250, the hot trick was to replace the resistor with a piece of cooper welding rod of the same size as the resistor. My XR250 ran pretty good and I never had a problem with it. Has anyone tried this trick on a 400EX? What's the purpose of the resistor? Thanks.

[motoboy66]

never heard of it, but i will try it, I have an old plug cap that I took off because the resistor went out. I'll let you know this weekend when I try it.