1999-2002 TRX400EX Fourtrax Service Manual, Page 67Get this manual

FUEL SYSTEM Apply vacuum to the vacuum portThe vacuum should maintainedAir should not flow through the valve ports when the vacuum is applied, and should flow when the vacuum is not applied
VALVE PORTS

THROTTLE VALVE
Removethe three screws, clamp and top coverRemovethe O-ring from the body groove
TOP COVER

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives