jetin?

[400ex men]

ok i have a 03 400ex stock pipe k&n no lid and a HotCams stg 1 i have a 155 in i think its a lil rich what you think its needs to be?

[bman9]

if you have a jet kit, just pet the jets in a figure it out. Trial and error.

[cals400ex]

i bet that is fairly close. you could try a 152 though. what elevation you at? what is the temperature your riding in?

[400ex men]

elevation is about 200 feet and temperature is any where from 20 to 100

[04-KFX400]

Just those temps will call for three different jet sizes. Air temp has a huge affect on jetting.

Largest (richest) of the three at 20 degrees

Smallest (leanest) of the three at 100 degrees

[cals400ex]

i usually change my mainjet at least twice a year too. a 150 might be just fine in the hot temps. in the cooler temps, you will want a larger mainjet. by seat of the pants, you probably won't notice much if any difference from a 152 and a 155. i always had a buddy with the same bike so i could drag race and tell which one it ran better with. it was a very minute difference, but we could always tell something since our bikes were near identical in speeds.