2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 449Get this manual
ELECTRICAL ('04'05) REPLACEMENT Remove the carburetor from the insulator and connecting hose (page 7-6)Remove the following:two torx screws and washersthrottle position sensorO-ringjointcollarO-ring TORX SCREWS, WASHERS
THROTTLE POSITION SENSOR Install new O-ring and the collar onto the carburetor body
Install new O-ring into the throttle position sensor grooveInstall the joint into the throttle valve shaft by aligning the joint tab with the shaft grooveInstall new throttle position sensor by aligning the sensor shaft tab with the joint tab groove