1986-1987 Honda TRX350 FourTrax 4X4, 1987-1989 TRX350D Foreman 4X4 Service Manual, Page 47Get this manual
FUEL SYSTEM Remove the throttle arm set screwPull the shaft out and remove the throttle valve with the arm and washer
Remove the two screws attaching the arm to the piston and separate the piston and jet needle from the arm