Questions about using 426 jetting on a 400

I read a post about using a 426 needle in a 400 carb for better mid range. I have a 99 and I am interested in the details of this setup. Clip position, main jet, pilot... I live in wa state apprx 2500' elev. Thanks

Try the '01 YZ426 jetting with a few variations.

#45 pilot

1 3/4 turns out

OBEJN needle, clip #3 (richer option)

#168 main jet

You will feel a major increase in mid-throttle power. The stock DVR needle is lean in the mid-range.

See: and look at the 4-stroke needle graph.

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