1999-2004 Honda TRX400EX FourTrax Service Manual, Page 76Get this manual
PILOT SCREW ADJUSTMENT -
IDLE DROP PROCEDURE
The pilot screw is factory pre-set and no adjustment is necessary unless the pilot screw is replacedUse tachometer with graduations of 50 rpm or smaller that will accurately indicate 50 rpm change
1Turn the pilot screw clockwise until it seats lightly, then back it out to the specification givenThis is an initial setting prior to the final pilot screw adjustment
CAUTION: Damage to the pilot screw seat will occur if the pilot screw is tightened against the seat
Pilot screw wrench 07908-4220201 INITIAL OPENING: 2-14 turns out