1999-2004 Honda TRX400EX FourTrax Service Manual, Page 77Get this manual
HIGH ALTITUDE ADJUSTMENT Below Main jet Pilot screw oDeninq Between 3,0008,000 ft
1 turns in from
The carburetor must be adjusted for high altitude riding (between 3,0008,000 ftl,OOO2,500 m)
STANDARD SETTING: Below 5,000 ft 11,500 ml HIGH ALTITUDE SETTING: Between 3,0008,000 ft (1.000 2,500 ml
The high altitude carburetor adjustment is performed as follows: Remove the carburetor (page 5-3) and the float chamber capReplace the standard main jet with the high altitude
HIGH ALTITUDE MAIN JET #142
Check that the O-ring on the chamber cap is in good condition and replace it with new one if necessaryInstall the chamber cap and the carburetorTurn-in the pilot screw the specified number of turns from the initial setting
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