2005-2011 Honda FourTrax Foreman TRX500 FE/FPE/FM/FPM/TM Service Manual, Page 125Get this manual
FUEL SYSTEM Remove the vacuum chamber cover, compression spring and diaphragm! vacuum piston from the buraler bodyVACUUM CHAMBER COVER
VA:ULIM PISTON
Be careful nor to damage the diaphragm
Turn the needle holder counterclockwise by using screwdriver while pressing it in and release the holder flange from the vacuum pistonRemove the needle holder, spring, jet needle and washer
NEEDLE HOLDER
Check the jet needle for stepped wearCheck the vacuum piston for wear or damageCheck the diaphragm for pin hole, deterioration or damageCheck the vacuum piston for smooth operation up and down in the carburetor bodyAir will leak out of the vacuum chamber if the dia phragm is damaged in any way, even with just pin hole