2005-2009 Honda TRX400EX/TRX400X Service Manual, Page 100Get this manual
FUEL SYSTEM Turn the throttle stop screw to align the butterfly throttle valve with the edge of the outside by-pass hole in the carburetor
THROTTLE STOP SCREW
Connect the following hoses as shown- air vent hosesair cut -off valve vacuum hosedrain hosefuel hose