Answer Hello Bud! To convert your model JGB285DET1BB over to NG you will need to purchase the tube/orifice holder assemblies. For the center burner use part number WB28K10626, for the left front burner use part number WB28K10810, for the left rear burner use part number WB28K10625, for the right front burner use part number WB28K10624, and for the right rear burner use part number WB28K10811. Thanks! Read More... Answered by AppliancePartsPros.com | Monday, May 21, 2012