Petcock Adapter/Tank thread dia:
H Series=  24mm x 1.0mm
S Series= 22mm x 1.0mm

Note: Filter diameters differ between S and H series.

     Early S Series                                  Late S Series
   51023-021/026                                     51023-039

Lever positions differ between the two.

Gaskets differ as the Early S requires a cone lever gasket.

Early S Series

 

Late S Series Teardown & Assembly