416ex jetting issues

[Sanddraging28]

trying to set up my brothers 02 416ex.
cant seem to get the jetting right.
he has the following

12.5 je piston 416cc
stock head
full hmf exhaust
white brothers stage 1 cam
white brothers stage 1 cdi
k&n with no airbox
110 race fuel

right now he has 158 main and 45 pilot needle on 3rd slot

any help would be great

thanks

[gojk]

What are the symptoms that lead you to believe you aren't jetted correctly? 158 seems a little small, but it should be pretty close.

[honda400ex2003]

Mine is in my sig. It runs awesome. Hope this helps, Steve

[Sanddraging28]

seems a little under powered. not getting a good idle and when he was riding it yesterday it was popping a little whenever he was going down a hill with no throttle input. and i believe the mixture screw is out about 4 turns. i thought a bought going to 162 main jet and leaving the pilot alone.
any help would be great

[gojk]

It is pretty normal to get slight pop on decel.

What do you mean by its not getting a good idle? Does it idle rough? Is it a low or high idle? 4 turns out seems like alot, maybe bump up the pilot a size or 2 if you are over 2-2.5 turns out.

By lack of power, does it seem flat at full throttle? If so, go larger on the main. Actually I would go big on the main and do some runs dropping the main one size at a time and see how it feels. Keeping the 400 rich is important because being lean causes it to overheat and lose HP.

Originally posted by gojk
What are the symptoms that lead you to believe you aren't jetted correctly? 158 seems a little small, but it should be pretty close.

yeah i run a 158 in my 400ex and it just has basic mods. but then again i dont know your altitude and temperature. race gas changes jetting doesnt it?