400 wont idle at startup

[kilabeez0]

all my friends bikes fire right up first try and hold idle. my 400 i have to play with the choke and ride it for a few minutes before it'll idle. why wont mine idle right away? i have a k&n filter and occasionally take the lid off but thats it.

[cals400ex]

removing the air box lid will definatly change the jetting.

try to install a 40 or 42 pilot jet and tinker with the fuel skrew on the bottom of the carb. on average i usually start around 2.5 turns out with a 42 pilot jet and tinker from there. a 40 should be fine for you though unless you plan on modding it more.

[kilabeez0]

wuts the difference between changing the main or the pilot?

[cals400ex]

the mainjet MAINLY constrols the fuel flow from around 3/4 to full throttle. the pilot jets MAINLY controls the fuel flow from idle to 1/4 throttle.