2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 132Get this manual
FUEL SYSTEM {'04'05) Turn the throttle stop screw to align the butterfly throttle valve with the edge of the outside by-pass hole in the carburetorInstall the accelerator pump (page 7-17)
ACCELERATOR PUMP
Install the diaphragm shaft into the float chamber through the boot while slowly turn it to prevent the boot from damagingSet the diaphragm rib into the groove properlyInstall the spring and accelerator pump coverDIAPHRAGM