250x with 400 carb problem

[rodenberg35]

I put a 400ex carb on my 250x and I have a dead spot. When I go from idle to wide open it falls on its face. If I start at 1/4 throttle then hit it every thing is ok. I have 175 and 48 jets in it but I think it is still lean. Does this sound normal

[Tom Lynn]

Wait a minute ur sayin with a 400ex carb on a 250x its running lean I have a 400ex carb with stock jetting on a ATC350X and its runnin rich so im buyin a 126 main jet (the stocker is a 132) and a 19 pilot jet I dont no wat the stocker is so u might wanna go even lower
Another thing it may be is the air fuel mixture- look at the back of the pipe if it is black there is a little screw (it looks like it is either brass or gold or summin it is a flat screwdriver) turn it out about 1½ turns out that helped mine alot but im turnin it back in and gettin jets so I have a little more flexibility

[rap169]

yes it sounds lean to me. I have the same mods to my motor and i had to increase my main jet alot largert than stock. i thought that stock would be too rich, but i was wrong

[rodenberg35]

I know that it sounds odd but I realy think its lean. I am gonna try an even bigger jet with a new plug so I can check how its burning.

Thanks