This Item listing is for the very distinctive conical shaped, knurled, gearbox clutch cable adjustment bolt and locknut - both parts are CNC manufactured as faithful replica of the original Norton Item.
However, if you have held one of these threaded adjusters you will know they are quite heavy for what they are. I am not entirely sure if they were also standard fitment on the M30/M40 and Manx models (although the large knurled adjuster would definitely had been very useful) - but I am sure that if they were fitted, you would have wanted to do something about the excess weight of the adjuster - so I decided to make an additional batch of these - where we have bored 6 additional lightening holdes radially around the conical part of the adjuster - when held in the hand alongside an original un-lightened version, the weight saving is significent.
So although I cannot say these lightened versions were an original Norton fitment, they are the type of mod the likes of many tuners might have done in period - and they certainly look very pretty on your racing or Sports model!
We also sell the 'normal' road version of this clutch cable adjuster (Item 0902) - and the information below is takien from that listing:
This knurled cable adjuster and locknut was fitted to both the upright type Norton gearbox, as well as the early to mid 1950's laydown gearbox that followed, on all models.
Apart from looking quite unusual - with its wide knurled head, and conical shape - it was extremely useful for adjusting your clutch lever while sat on the bike, you could just reach down with your right hand, loosen off the lower locknut, which had the same width knurl, then either wind out or wind in the long thread of the cable adjuster until the clutch lever had the correct level of free play, then tighten the locknut up again to the cover of the gearbox. In addition, the locknut on its lower part also had a hex milled onto it - providing a nut for an open ended spanner, as well as the knurl - if you wanted to ensure it did not come loose again once adjusted.
Because the original Norton adjuster bolt was made of brass, and because over a period of time this adjuster tended to get abused by owners - i.e. once it got still due to lack of grease, it was not uncommon for owners to try and turn it with a pair of pliers!, it is now very unusual to find a Norton that still has the knurl in good condition - normally they are all chewed, and sometimes the knurl is entirely smooth. This alleviates the whole purpose of the design - as with a lovely crisp knurl, the adjuster is a delight to use.
Our items are CNC manufactured in brass to the exact dimensions of the original Norton design. The shaft of the adjuster bolt is the same length and internal cable diameter of the original - it even has the counterbore at the bottom of the cable bore. The taper on the lower part of the knurled adjuster is the same dimensions as original - and as you can see from one of accompanyning photographs - the knurled locknuts have teh same internal taper to the top of the locknut - designed so that the locknut would screw right up to the taper on the adjuster bolt, to give as much cable adjustment as possible. Finally the locknuts also have the correct Whitworth spanner size milled onto them, including the original chamfer underneath to stop them fouling and scratching the gearbox cover.
We also send these away to our UK based plater once machined, to ensure they are plated with the correct nickel plated finish. Although bright in the photograph, these will dull-off with time once on the bike.
Not cheap because of the amount of effort to produce them - but they are correct and period for your Norton restoration, and as well as being very useful - being placed in a prominent position, they also look very pretty! And obviously - for this 'lightened' version, we have to perform an additional milling operation to bore the 6 radial holes, all central to the adjuster, so the holes look correctly positioned when viewed from the top.
As a final point - as you can see in the final photograph, we assemble the locknut onto the threaded adjuster with (Castrol) high melting point grease before placing in a sealable bag so the operation is smooth. It is worth remembering when fitting these - that the gearbox cover (either upright or laydown gearbox) should have its thread fully cleaned of any dirt before fitting, to ensure smooth continued operation.
For those that are uncomfortable in making up their own clutch cables to include this adjuster - please email us at sales@racingvincent.co.uk, as we are considering having a batch of clutch cables made, with these adjusters fitted, from a top UK cable manufacturer.
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