Pump Diaphrams- Standard #JDKH18 (on left), and Honda Diaphragm #JDKH04 (on right) Pump Diaphrams- Standard #JDKH18 (on left), and Honda Diaphragm #JDKH04 (on right) Pump diaphram rivet is longer on the Honda diaphragm to shorten pump stroke and reduce fuel flow. JDJetting Carburetor Parts -Picture Gallery