-JdK- At the end of the flat tank era, Walter Moore not only designed an OHC engine; he also designed the first cradle frame to be used by Norton. All of these used the Royal Enfield rear hub.
From top to bottom:
- a 1928 CS1 frame; this is the three-stay frame used for Moore CS1/ES2 engines.
- a 1929 ES2 frame; CS1 and ES2 frames from the end of 1927 up to 1930 are identical.
- a 1931 CS1 frame designed for the Carroll OHC engine; still a three-stay frame but lower than the Moore-frames and using a larger diameter front-down tube (note that the dolls-head Norton box as fitted is not correct; a Sturmey-Archer box should be fitted).
It is worth mentioning that CJ/JE models used two stay frames in combination with Enfield rear hubs.