1932-34 (Approx) 4 Speed Sturmey Archer Gearbox - Cam Plate And Quadrant Spindle Bush's (Pair)

Product no.: 1053 A2/344SA

In stock

£26.30
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This listing is for a pair of the plain Phospher Bronze bush's of similar dimensions to the later Norton upright type gearbox shell, but of the shorter length that the final Sturmey Archer type gearbox spindlehousing design used - read the further information below:

Price is for a pair of bushes (i.e. to fit one gearbox shell) 

Background Information:

Up until sometime in 1934, Norton Notors used a variety of both 3 speed and 4 speed Sturmey Archer gearbox''s - before Sturmey Archer (then owned by Raleigh motorcycles) ceased trading in 1934.  At that time, rather than going to Albion or Burman (as many other manufacturers did), they decided to make their own in-house gearbox, based on the last Sturmey Archer gearbox fitted - but with many subtle improvements.  

Around this interim period of 1933 - 35, there do seem to be different variations of gearboxs shown before the standard Norton Upright (Dollshead) gearbox design was finalised.

Although I am no expert on all the Sturmey Archer Gearbox variations, at the same time as manufacturing a batch of Item 1051 selector bushes for the standard 1934 onwards gearbox shell, we also made a small batch of phospher bronze bushes, that are identical to the later bushes - except they are made with a narrower width of 0.750", which is length of the gearbox shell in the photo.

It is importnat to note that the gearbox shell shown in the photo (which has a casting identification number of 'EV130' - the later gearbox shell normally has a casting number of 'N8001') is believed to be a later 4 speed Sturmey Archer gearbox shell, of the type fitted up to 1934 - but as manufactured it does not have bushes fitted for the selector camplate or quadrant at all - instead they run directly in the aluminium shell holes.

Undoubtedly - Norton must have seen this was a known weakness - and once the bore holes in alloy shell were worn, affecting a repair would be difficult - so no doubt specified that their own gearbox would have bronze bushes fitted, as one of their design improvements. 

Note also that in the accompanying photographs, that the bored holes for the selector camplate/quadrant has internal counterbores to accept felt seals internally, rather than the single external felt seal used on the later Norton gearbox shell design. 

Knowing that owners of earlier Norton models fitted with Sturmey Archer gearbox's, may have found that their gearbox has excessive play of the camplate or quadrant spindle - we have made a small batch of phosphor bronze bearings which share the same dimensions of the later bronze bushes (Item 1051) - other than they are of the shorter 0.750" length - which is the bore dimension of the Sturmey Archer gearbox shell shown in the photographs.

Therefore, if your original gearbox is similar to the one in the photos, but has badly worn or eccentric bore holes - one logical alternative would be to bore out the original alloy holes, and fit bronze bushes of similar design to the later type bushes.

It is very important before purchasing these bushes though, to understand that to fit these - would first require confirming the dimensions of your gearbox are as per this gearbox shell  . . . and that you realise you will need to bore the original gearbox shell holes out - to fit these new bushes (and as per the later type bushes - these are made to press into a 0.8125" (or 13/16") bore hole.  This would require good engineering knowledge and equipment to perform properly - so if you do not feel confident in carrying out this task yourself . . . then we would recommend not buying these bushes - and of course anyone carrying out the task does so at their own risk.

But all that said - if you do wish to fit bronze bushes - we can offer these bushes, as per Item 1051, but allowing the original Sturmey Archer type internal felt seals to be fitted. 

Price is per pair (i.e two bushes – required for one gearbox shell).  As with Item 1051 - we have also made just a few additional bushes of this type - but with an internal bore fractionally undersize from Std,  (i.e. 1.5 thou undersize), in case you feel your camplate/quadrant shaft is also worn - please email if requiring these

The accompanyning photographs show a comparison of the Sturmey Archer and Norton type gearbox shells side by side, as well as close ups of the earlier shell - in one of those photographs the original felt seal is shown still fitted to the spindle of the selector camplate - with the new bush fitted above it.

We recommend you email us on sales@racingvincent.co.uk to confirm any further details if unsure your gearbox shell is the same as the type shown here. 

As a final point on Sturmey Archer gearbox's - we are currently (October 2021) having a range of kickstart springs made for those Norton models using this make of gearbox's from late 1920's up to 1934, and should be making a batch of the smaller diameter (0.250") gearbox shell studs and cover nuts in the near future - email for more details. 

 

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