Update 9/2/19: Please note, we ran out of these two months ago, but I was expecting a new batch to come in any time. Unfortunately my CNC manufacturer for these has suffered a stroke and is not now able to make them. I am going to look at us making these ourselves on our CNC in the next two months - but if you place an order please bear this in mind. Additionally, I cannot confirm the price will be as shown - although it should be close. Thx.
This is a faithful reproduction of the distinctive Norton 'large bowl' petrol tap, as fitted to both Norton International and pre-featherbed Manx's - but with the big advantage that these items are manufactured in stainless steel, and therefore will never need re-chroming.
As always with the Norton parts I manufacture, I have endeavoured to ensure they look identical to the original and in this case, the main body and taper tap design is faithfully copied from an original item (unlike many of the copies I have seen in the past).
Inside the bowl, the design is also identical, with the same thread and a copper gauze, retained by a circlip. I have also ensured that the top mating face includes the special circular ridges, which may look like rough machining – but were actually put in intentionally, so they would bite into the red fibre washer, used to seal the tap to the petrol tank. I use a modern retaining circlip, as the original thin wire type was prone to rusting and then breaking. By the way – I think the reason for the wide bodied bowl, was because this allowed a greater surface area for the fuel to pass through the gauze, therefore, for racing there was less chance of fuel starvation.
Obviously, our taps have the same large bore ‘through’ hole as the original. A main feature of this particular reproduction is that the body is CNC machined and then polished afterwards, the result being that it looks almost indistinguishable from an original chromed item – if I say so myself, the quality of these items is extremely good, with no visible machining marks. This high quality of machining has meant it has been possible to polish the item to look like chrome, so as well as looking good known they will never need re-chroming. This is an important factor as one of the biggest problems with the original taps, which were made from brass then chromed, is that over the years the chrome will rub away – or a past owner did not have a spanner big enough for the large Hex spanner face, and therefore used a chisel to remove the tap!
We have tried to have original taps re-chromed in the past but have found this is rarely successful, because unless you can find a chromer prepared to seal off the taper tap area, you are likely to find the taper of the tap will leak on re-assembly. As a point of detail around the taper tap itself, we were originally concerned with manufacturing this tap in stainless steel, as we had heard rumours that stainless on stainless can seize. Well, first of all it is worth pointing out that brass lever taps will often seize anyway, particularly if not being used regularly – it is an inevitable consequence of this taper design. However, we experimented with different designs – including manufacturing two examples of the tapered pin with grooves to take special fuel resistant (and very expensive!) miniature ‘O’ rings, but in the end we found it was unnecessary. I did tests back to back, and found that because of the high quality of machining tolerance achievable with modern CNC machines, we were able to achieve leak free results using the original taper design and stainless steel. Taps were left holding fuel for a period of days (up to two weeks), and then checked for leaks and turned on and off. No leaks were found and the tap itself – which is always stiff because of the design, showed no signs of seizing.
Finally, it is worth pointing out that, as part of the production process, the tapered pin is individually fitted to the tap body, and its taper is ground in, using fine grinding paste, before the final fuel hole is drilled through the taper pin. This is probably overkill – but is an extra insurance against leaking. Finally, each tap is assembled using a fine smear of Rocol molybdenum grease, which is a very good inhibitor against seizing for stainless steel. The one concession to modern design I have built into these taps, is the use of a stainless steel nyloc nut, instead of the original nut and split pin design. This is virtually invisible, as the tap is normally rotated so the nut is not showing, and avoids the need to drill the thread for a split pin – which often break off on originals.