This is the spring that was fitted in the mid/late 1920's up to approximately 1930-31, for those models that were fitted with the large right side mounted rear brake drum (which I believe were supplied by Royal Enfield originally), and then used a one piece crossover shaft attached to the brake pedal - so a left foot brake pedal could be used. See the attached pictures, taken from the 1929 CS1/ES2 Norton Spare Parts List - which show the brake pedal and associated parts for the rear brake mechanism - and shows clearly the spring offered here - Original Part Number 4504.
As shown in the catalog - it was standard fitment on the Norton 3 - stay frame up until Norton introduced their own brake drums and mechanism in approximately 1931/32 on the left side of the bike- at which time they changed over to what become the standard brake pedal with return spring mounted on the brake plate. Therefore the later 3 stay frames with combined rear hub/sprocket should not need this type of spring.
Other models (i.e. OHV and possibly some SV) with two stay rear frame, but also employing the brake hub on the Timing side of the bike, and a crossover shaft/brake pedal will also have employed this spring - and our original Norton pattern shown in the second photograph - which was used as the pattern for replicating this spring came from a 1930/31 Model 18. There is also a picture of a restored 1930 Model 18, so you can see the type of brake mechanism that fitted this type of spring.
The spring fits onto the crossoveer shaft of the brake pedal and loops onto the frame tube, it being fitted on the brake lever side of the crossover shaft.
This is now an extremely rare spring to find in its original form and ours are copied directly from an original Norton pattern by our specialist UK spring manufacturer. Not as cheap as some springs - as setup costs are high for a relatively small batch quantity . . . but hopefully if you have an original with corrosion or broken . .. at least you know this one is correct!
nd brake pedal. This spring fits behind the brake pedal and has a loop that acts on the frame tube. This spring is copied from an original Norton pattern - see listing for more detail. Price is Each
Price is each.
We used a genuine original Sturmey Archer (for Norton models) kickstart spring for the pattern for manufacturing these springs - so they are as per originals.
This spring is unusual, in that it is has forward facing tang and loop, which fed through a hole in the kickstart spring cover (see accompanyning photos), and then looped behind the shaft of the kickstart lever. The length that this tang protruded is important, as other Sturmey Archer gearbox's had a similar spring - but with a shorter length protruding (see also Item 1064).
The length the tang protrudes on this spring is approximately: 44mm
The outer diameter of the spring is approximately: 47.5mm
It is difficult to be definitive about exactly which Sturmey Archer Gearbox's and models this spring was fitted to - but it is certainly of the type that was fitted to the sporting Norton Models from 1927 through to approximately 1932 - as it is listed in the 1927/28 Norton Spare Parts catalog for Walter Moore type CS1 and ES2 models. At this point the spring was shown as part number 4585. I cannot be entirely sure - but I believe the gearbox was known as the CRS type gearbox (please email me if you think I have got this wrong!).
It was then shown again in the 1930-31 Spare Parts Catalog, by which time this gearbox was now being fitted to the newly introduced Arthur Carroll type SOHC CS1 engine, as well as the ES2 models. By this time the part number had changed to 5X44. See accompanyning photos for exerts of both these catalog pictures.
The following year (i.e. 1932) the Sturmey Archer 4 speed gearbox was introduced for the SOHC Mod30/40 models with a different kickstarter spring type (see Item 1066) - but the 3 speed gearbox was still listed for the CS1 models - so although I cannot be sure if the spring design changed, the 1932 3 speed may have continued to use this spring type - and it may have also been used on other models at that point in time (again, please email if you have a 3 speed of 1932-34 design and can confirm this, thx).
This spring may have also been fitted to other manufacturers models fitted with Sturmey Archer 3 speed gearbox's from mid 1920's to early 1930's - if unsure, the important dimensions to check are shown above - the distance the tang protrudes to reach the kickstarter shaft, and the width of the spring (and again - I would be happy to update this listing if anyone knows of other models using it).
As a final point - as at time of the writing this listing (Jan 2022) - I am in the process of having a small batch of the spring covers manufactured - as shown in the centre of the photo with the springs and covers together. These were tin covers (although we may need to machine from solid), with a hole for the forward facing tang to protrude. Email us on sales@racingvincent.co.uk if you wish to reserve one.
This is now an extremely difficult spring to find, and many original gearbox's are likely to be suffering with the original spring worn and tired - this new spring should help revitalise the kickstart lever returning!
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