why doesnt my 400ex want to run right unless its all or nothing? it runs like trash if your not yokin, gasin, smackin,goosin,twistin, or breakin the throttle?

anyone know?

 

sounds like your jets are messed up or trash in the carb

 

factory jet is 148. i put a 416 in it, with a 170. does that seem kinda high? shud i go to a 150?

 

try going to a 150, and stepping it up from there

 

You went to a 416 but did you open up the airbox and install an aftermarket exhaust?
If the airbox isn't opened up (take the lid off) then you jumped up to too big of a main jet.

 

yeah. got a open air box. and i have a white bros pipe... also runnning 115 octane. nology coil and a dynatek cdi.

it just breaks up 1/4 to 1/2 trottle?????????????????????????

 

You went to a 416, what compression did you bump it up to?
If you are running 12:1 or less, 115 octane is not needed and would actually be hindering performance. I would not bump up to race fuel unless you had 13:1 or higher. Then you might want to run 50/50 race gas/pump premium.
Ride it around at 1/2 throttle and then pull the plug and check the color. Tan is the best, black is too rich.

 

Thats sounds a little high.

 

fixed it!!!!!!! i just pulled the needle out to the 4th notch and put a 180 main jet.

runs like a top...