2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 480Get this manual
IGNITION SYSTEM (After '05) CARBURETOR SWITCH Remove the top cover (page 3-5)Remove the rear fender (page 3-7)Disconnect the ICM 4P black connectorCheck for continuity between the terminals of the connectorTERMINALSPinkblack terminal (+)Green terminal (-) There should be continuity when the throttle drum is fully closed and no continuity when the throttle drum is open
If the carburetor switch operation is incorrect, disconnect the carburetor switch 2P natural connector and check for continuity between the terminals of the switch sideTHROTTLE DRUM CLOSED: THROTTLE DRUM OPEN: CONTINUITY NO CONTINUITY