I have a 160 main jet with the needle in the middle. That is about the best combo i have found for mine, but of course, it would be different for a stock bike. You really have to just do some trial and error. Try different sizes and ride it for a while and then check the spark plug ( when it cools down). It should be a light brown to dark gray color on the tip of the electrode.
2001 Honda 300ex
laeger +2 aarms, Lonestar +4 axle, Works shocks, AC bumper and nerfs, Wiseco 11:1 piston, White Bro's cam and valve springs, ported and polished head, Curtis Sparks x-4 exhaust, uni filter, 19" and 18" holeshot mx's on douglas red label wheels, pro-design kill switch, 13, 14, 36, 38 sprocket specialist sprockets, 160 main jet, and a clarke plastic gas tank, pc'ed frame, a-arms, swingarm, steering stem, and pegs.
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