1986-1989 Honda TRX250 FourTrax 250R Service Manual, Page 46Get this manual
FUEL SYSTEM Unscrew the lock nut and remove the choke idle speed knob
Check the valve seat and needle for damage or deterioration
(2) VALVE SEAT
Blow open all jets and body openings with compressed air
CARBURETOR BODY ASSEMBLY
Install the chokeidle speed knob af)d tighten the lock nutInstall the air screw and return it to its original position as noted during removal