1998-2001 Honda Fourtrax Foreman TRX450S, TRX450ES Factory Service Manual, Page 101Get this manual
FUEL SYSTEM
AIR CUT OFF VALVE
Install he O-rings, air jet and ai cut off valve
Note the direction oft he air iet as shown
Install and ighten the Screw secur-ely_
DIAPHRAGMVACUUM PISTON
Insta ll he needle cl ip on the jet need le