another jetting ? pro circut t-4

[speedydog5]

Just wondering what you guys run on jetting for a t-4 slip on for a 400 ex and do I need to change pilot jet to or adjust needle I,m at about 700 ft in Chicago IL thanks

[250EXpwns]

I don't know what all's in my 400ex's carb since I had the dealer rejet it but I do know that my MJ is a 155 Dyno. My elevation is about the same as yours.

[cals400ex]

run a keihin 152 mainjet (i assume your air box lid is on and the pipe is your only mod). turn the fuel skrew out 2.75 turns from lightly seated with the stock pilot jet. leave the needle alone for now. if you want you can get a larger pilot jet but it won't be a "must have."

[400extracc]

i have t-4 with k&n and holes in lid.............152 main 2.5 turns needle clip 2 down and 1 up pilot.......bang on!

[speedydog5]

just curious what stock is on jets and air screw and needle pos, pro circuit told me to go 158 main and58 pilot that seems like allot

[400extracc]

yes it is...........................i don't remember what main jet and pilot they gave me but it as way to big!

[cals400ex]

the stock main is a 148 keihin and the stock pilot is a 38 keihin. needle clip from factory is in middle position (3rd). stock fuel skrew location is 2.25 turns out from lightly seated.

i would try the jetting i told you. it should run good. you can bump up the pilot to a 40 or 42 if you want, but it is not 100% manditory.