Head gasket replaces OEM 12251-MG9-306 for GL1100 and GL1200 and priced per each. GL1100 cylinder bore is 75 mm (2.953 in.) and GL1200 bore is 75.5 mm (2.97 in.)
NOTE: Prior to installation, the Honda GL1100 Work Shop Manual, page 7-9, suggests that old gaskets will come off easier by soaking with solvent or spraying with gasket remover and never suggests use of an abrasive, such as sandpaper. Cylinder heads should always be checked for warpage in an X pattern with a machinist's straight edge and feeler gauge.
The Honda Manuals (GL1100, page 7-14 and GL1200, page 7-19) note that head gaskets are graphite-coated and do not require a sealant. Installation should be dry fitted to create a properly bonded seal and use of a sealant may compromise its bonding properties.