dyno jet sucks they told me to use a 130 MJ in my yfz when its a stock 158 which makes no sense and their instructions say u can take the top off the carb off without taking the carb out.......which is nearly impossible seeings how the frame is in the way

 

in my opinion

 

Hey-- where's the pilot screw on the 400ex?

 

a 130 does seem small. however, dynojets uses a different numbering pattern than keihin does. however, i have been told that a keihin 148 is equivalent to a 142 DJ. this was in a 400ex. i can't promise you this exactly, but this is what i have heard.

 

the fuel screw is located on the bottom of the carb. it might be hard to see when the carb is still on teh bike. it is a little bronze colored screw that you move with a flat blade screwdriver. it is behind the idle adjustment bracket.