1985-1987 Honda TRX 250 Fourtrax 250 Service Manual, Page 44Get this manual
FUEL SYSTEM PISTON THROTILE VALVE NOTE
111 PISTON
VALVE ARM
The butterfly throttle valve attaching screws are staked and
the valve can not be removedRemove the carburetor top cover by removing the three
screwsRemove the throttle valve arm set screw
Pull the shaft out and remove the throttle valve and washer