-JdK- Now here's a nice challenge; I've had the gearbox in the photo above for many years and after a long time found the positive stop mechanism for it and aimed to fit it to my 1931 CS1. To my surprise it did not fit! The bolt and 'cam plate quadrant lever' foul the frame.
This was a surprise at the gearbox shell is clearly labelled EIV 30F which identifies it as a Norton box according to the S-A catalogue.
Then last week I got the photo's below from Thomas in Germany who has two S-A 4-speed gearboxes and they differ in the position of this 'cam plate quadrant lever'. It can be in a high or low position. Note that inside the box, the 'cam plate' and 'indexing plunger' will also be at a different postion.
Now the question is; as both boxes are clearly for Norton motorcycles, which models do they fit to? My guess is that the box with the lever at the lower position will fit the 1931 and later models with the heavier frames. And is the box with the lever on the top position meant for the 1927-1930 models?
Please contact us when you can help.
Postscript: Chris in the UK contacted us with the following that explains these boxes were used in Broughs: "the 11-50 Broughs used the high quadrants and my original box (the Brough Superior Club has the build sheets for almost all Broughs after the early 20sand it includes gearbox details) was a B455A number 11089. I have obtained a shell E1V 30F stamped B455A and number 13003, this has the high quadrant and the layshaft bearing is a top hat bush and must require a layshaft with a recess to accommodate it."