Log in

View Full Version : carb experts



drchoicey
11-21-2006, 09:49 PM
educated guesses for starting points

2004 400ex

3,3" holes in back of airbox lid
stock element and cage
FMF Q2
stock headpipes

a/f mixture screw?

pilot ?

needle clip position ?

main ?

thank you

the doctor

hornetgod13
11-22-2006, 12:00 AM
Your altitude will be a factor for your main jet size. Can't go wrong with a #42 pilot. Needle on middle setting (3rd). Fuel/Air screw at 2 to 2 1/2 turns out.

cals400ex
11-22-2006, 10:43 AM
i would probably start around a keihin 160....for starters. however, jetting will change on a daily basis due to temperature, altitude, humidity, etc. so without knowing a few of those factors it is hard to tell. hornet gave a good starting point for the other jets. in the winter months i needed to move my needle clip down to the 4th position. besides that, it should work fine.

Wheelie
11-22-2006, 09:40 PM
Stock or #40 pilot, needle in the stock position, and a 152 main.

2.5 turns on the screw.

drchoicey
11-22-2006, 10:29 PM
thank you

drchoicey
12-06-2006, 10:59 PM
thanx wheelie,
your jetting recommendations were spot on
ps
i highly recommend the q2 from fmf
i just put one on the kids quad
noticeable torque increase
fully 5 pounds lighter than stock
loud enough to make the kid happy
quiet enough to keep me happy
have a nice ride
the doctor