Help With Jetting

[skipdog]

I am looking for the correct jetting for my set up and need help.I have a 03 400ex with aluminum air box and white bros pipe.I am also going to get the curtis sparks timing key soon.I was told by white bros i dont need to change the jets but i find that hard to beleive.Also i am going to put louver (sp) in the lid of the air box soon.I just want to know what jet size i should use.Thank you.

[BigBore24]

i would bump up to a 40 pilot jet and you will just have to play with the main to get it dialed in. i would start around a 155 and work up from there. ride it a short bit and pay attention to how it pulls throughout the entire throttle spectrum. go with the jet that feels the best to you