Jetting help

[santafood]

Hey, Just bought a used 400ex and was wanting some carb jetting help from some experienced riders and mechanics. The bike has a 440 big bore kit, high comp, K/N filter (no lid), and a white bros e series exhaust. just wondering if someone could throw me a ballpark number for the jets. Any help would be great, thanks.

Btw, the choke mechanism is also off which i was originally planning on putting back on for statring purposes but was wondering if i should or not. does it help with airflow to the carb?

[FF1O5]

if the previous owner installd a 42 pilot jet the choke being removed will not be a problem to start it,just pump the throttle a few times before starting and you should be good,but you might have to hold the throttle easy for a min. or two untill it gets a little warmed up.The removal of the choke DOES slightly increase the airflow through the carb.Judging by the mods the previous owner installed it should be jetted correctly,pull your plug and check the color,it should be light tan to grey.hope this helps.

If the plug is not tan goto the tech article section on this site and look at the spark plug color chart to see what is causing the color(ie.:lean or rich)

[cals400ex]

its hard to tell without knowing a little more info. however, for a starting point i would try this:

160 keihin mainjet, needle clip in 4th position from the top, and a 42 pilot jet at 3 turns out on the fuel screw