PUB suffffered an embarrassing ‘almost breakdown’, and provided the mid-day entertainment at her club’s annual rally
PUB suffered an embarrassing ‘almost breakdown’, and provided the mid-day entertainment at her club’s annual rally
PUB has been fairly busy in the workshop, but mostly on cleaning up jobs, which she hates. The pre-war project has various gearbox parts – almost enough to assemble two boxes with. All parts, however, were smothered with 80 year-old grease, and the casing was packed with the stuff. Very messy to clean off – neither does PUB have a parts washer (something she should perhaps have acquired?). The rear suspension springboxes (this is a VincentHRD, so of course it has rear suspension) were also greased, but they are unsealed so that grease was filthy to boot. Previous owner was of that breed who dismantled machines completely, down to the last nut and bolt. He did sometimes keep bits together in bags and boxes, but much of that regime has failed to survive a number of moves and successive owners. He also owned and dismantled a number of similar bikes, resulting in PUB’s jigsaw having many pieces from other puzzles, and a lot of pieces lost along the way. So it turns out that one gearbox is missing a 33t sleeve gear and sundry smaller bits, whilst the second has a seriously undersize layshaft (this, it would appear, ever since new!). Neither of them has the strange sized Burman output bearing (originally Fisher 61207, 72mm OD and 1½ inch ID!). However Draganfly list these, as well as some of those smaller parts so PUB is currently awaiting delivery. Then she must decide whether to further mix-and-match to make up one cluster, or await finding those missing parts.
It is expected that this will happen a lot, so progress will be slow, and only in little spurts when a bit of enthusiasm recovers. Meanwhile Norton John has found that his New Imperial speedometer does not work and had given it to PUB to look at. As outlined in some past columns (eg. RC131, March 2015), PUB is familiar with the internals of the Smiths/Jaeger ‘chronometric’ instruments, and can occasionally repair them if she is lucky enough to possess the required spare part. However, not all speedos are chronometric (or even ‘isochronous’ as Bonniksen described theirs).
The most common type on later machines is magnetic – in which the cable spins a magnet close to an aluminium disc to which is attached the needle. When the magnet spins close to the conducting aluminium it generates circulating current within that disc. That current (known as an eddy-current) produces its own magnetic field (like any other electromagnet), which interacts with the spinning magnet’s own field (basic physics of action and reaction). The result is that the aluminium disc, although of nonmagnetic metal, is dragged around against its restraining hairspring. Eddy currents, by the way, are also why dynamos and alternators utilise ‘laminated’ ironwork, which is permeable to the magnetic field but presents a resistance at each lamination interface to electrical currents. The result is much smaller eddy-currents, and correspondingly reduced power loss and heating. PUB has only broken into magnetic instruments once or twice (they are usually pressed together, not screwed).
However John’s New Imp speedo is not one of those either, but being a vintage bike it sports a ‘Watford’ instrument, made by S. North & Sons. From the bulbous casing this was rightly judged to be a centrifugal type, somewhat like a miniature of the flyball governor one might see on a traction engine. As speed rises the balls tend to fly outwards (against gravity and/or springs), with links pulling an actuator sleeve on the spindle. This sleeve, in turn operates gearing to a needle in the case of a speedometer (or a valve in the case of the steam engine governor). When
PUB initially looked at the instrument she felt something fall onto her knee, which a search proved to be a ball bearing. This and the presence of obviously loose parts inside was not an encouraging start. PUB had never seen inside a Watford type before, but agreed to take it away and see what could be done.
At home the first problem was how to get it apart once the bezel and glass were removed. It looks as though the brass case should slide off the zinc alloy casting, but such force as wisdom suggested might be applied refused to budge anything. Given that zinc alloy has a habit of ‘growing’ with time that approach was stopped, and likely screws in the face undone. Sure enough, that brought most of ‘the works’ out, but without revealing how the main spindle, which was rattling around loose, was supposed to be retained. One more 1/8-inch ballbearing was sitting in a recess at the bottom, and first impressions were that significant parts must be missing. However, when a speck of debris was spied down a hole and investigated, it turned out to be a minute 1/16-inch ballbearing. Eventually six such balls were found stuck in various corners – unfortunately significantly less than there should have been.
As may be seen in one of the photos the central spindle carries an inclined weight, on its own pivot. When the spindle is spun by the cable, the unrestrained sides of that weight tends to fly outwards, and a link pulls the brass bush down. That motion is transferred, via a sliding joint, to a gear quadrant and the pointer. But how was the spindle supposed to be supported? Eventually PUB recognised that the castellated item at the bottom must be the outer of a bearing, and should have been filled with 1/8-inch balls running directly on the spindle bottom chamfer. Similarly, at the smaller diameter pointed top, the spindle did not locate in a bushing, as it appeared, but in a tiny inverted cup
The ‘guts’ of the Watford speedometer mechanism. Tapers top and bottom form the inners of two ballraces. Castellated item is the bottom cup, inhabited by 1/8” balls, whilst the tiny top cup is held in its adjustable mount, and accepts equally tiny 1/16” balls. The inclined weight flings out towards horizontal (like the balls of a flyball governor) when spun round. A link from the weight pulls and pushes the brass sleeve up and down – eventually translated into the speed indication which should have been filled with 1/16-inch balls. Investigation revealed that both cups were threaded in place and so adjustable, but with the bottom one not accessible after assembly. Additionally, one or other cup must be upside down during assembly, or trial assembly, making retention of the balls tricky. It only requires about 1/16-inch (60 thous) end float for those tiny balls to be able to fall completely clear.
In any case, PUB had no such balls, although her spares box did provide some of the 1/8-inch size. So to make some progress, she bent up a small ring from a piece of 1/16-inch brass rod (possibly brazing rod). This trick was learned from Titch Allen, who frequently used it on the bottom race of his sidecar outfits, where the extra friction substituted for a steering damper. Not only would this substitute for a ring of balls, but it would be much less liable to fall out during trial assemblies – a number of which had to be made. This was necessary to establish a bottom bearing adjustment (and then lock it into place) which would satisfactorily align the little gear at the top of the spindle. Then a fine adjustment of the top bearing could be made as its cup is threaded into place, with a locking screw, clearly for the purpose.
A few other minor issues needed to be diagnosed, all apparently the result of the unit having been apart previously (a previous custodian, possibly even more puzzled than PUB, appeared to have ‘shovelled’ the remains back in, and just refitted it). Surprise, surprise, operated from a battery powered drill, the instrument registered speed and mileage again! PUB has subsequently bought some 1/16-inch balls (off the internet) – two or three of which she promptly lost just getting them out of the packet. However, with some difficulty, the brass ring has now been replaced with the correct balls, and the fine adjustment reset to suit. The ring trick would probably have been fine for a vintage machine never destined for big mileages, and was definitely easier. However John will be getting a properly repaired and working speedometer back.
Meanwhile summer is here (although the excessive heat of June is long gone, replaced by showers), and PUB has been out on the road. On a longish trip down Bristol way, to a rally, the PUB Vincent seemed to go OK, as it has done on shorter trips over the winter. If it could do the same all the way up to the Lake District for the VOC Annual Rally, then last year’s hiccups might be considered gone, notwithstanding that PUB would not know quite what had done the trick. However, remembering last year’s congestion on the M6, which made typical M25 traffic look like an F1 Grand Prix, a route up the western side of the country by A1/A1M followed by crossing
over from Wetherby to Kirkby Lonsdale was chosen, as it offered more opportunities for a change of route if necessary.
In fact the trip proved to be straightforward, and mostly dry almost to the destination. At Ingleton, just before journey’s end, PUB took a detour up the B6255 to see the Ribblehead viaduct. Built for the Midland Railway in 1870 to 1874, it is 440 yards long and rises 104 feet above the valley floor. The work cost the lives of approximately 100 navvies killed by accidents, fights, and smallpox, such that the railway company even paid for an expansion of the local churchyard! No long exploratory stop was made due to continuing showers, and the 200-plus miles already done, although the viaduct and its surroundings certainly warranted it.
The rally organisers had made a special effort to show as many Vincent-HRD models as they could attract, to mark 90 years of the Vincent HRD (not including the HRD years under Howard Davies). Their efforts were well rewarded, for in all her years PUB has never seen such an array, starting with a 1926 Howard Davies built HRD (and not PUB’s own, but a well restored model belonging to Arthur Farrow). Andrew Walker had one of Phil Vincent’s earliest models, with a ‘Seeley’ type triangulated frame on show, in addition to a number of other rare and concours models (for which he won awards). In the ‘industrial’ corner, where Vincent-powered products such as ‘Bullows’ compressor, and a fearsome looking ‘Versatiller’ were exhibited, there were also the remains of a Picador engine. Unlike the industrial engines, which were small two-strokes, the Picador was a full blooded Vincent twin, adapted to power an ML-made drone (for military target practice) by replacing the motorcycle gearbox with a bevel box to drive a propeller. Factory tuning provided another 20bhp over the standard Rapide figure, but considerable development and beefing up of the bottom end was required to permit continuous operation at this rating. At the other end of the scale the most recent ‘special’ on view was a Black Shadow converted to a trike (no parts butchered, and all reversible) – a real conversation piece.
On the following day the nearby village of Clapham were holding a fête and classic car show, so the club had agreed to take their ride that way and exhibit the Vincents
for the day. However, come morning it was bucketing with rain, and many, including PUB, considered staying in the rugby club bar for the day instead. However, the rain eased, and most then opted to go by the alternative short route – but PUB was too slow getting ready, and had to puzzle out her own way. The day was rounded off with a fine meal in good company courtesy of the rugby club staff, with no need to break out the camping stove all weekend.
Although a Sunday night stopover was also available, poor weather was forecast again, so a ‘dash for home’ seemed like a good idea and PUB, in company with Morini Alan, set off for the M6 south (less traffic expected than on the Friday). However, after a top up at the local filling station, the PUB Vincent started to hesitate, and gradually deteriorated into significant misfiring. Naturally first thoughts were that last year’s issues had returned, and an exploratory stop was made just before joining the motorway. Nothing obvious being found, PUB did not dare start the long motorway route home. Morini Alan waved as he left her there (to be fair he did check that she had a phone, but not that it was charged, which it often is not). As the bike was still running, it seemed a good idea to creep back to the rugby club, where help, spares, and tea/coffee would be available. It continued to run very badly, leading to a concern whether the ‘top up’ had been with diesel! However, revisiting the garage, where they traced the sale, eliminated that possibility.
Back on the campsite PUB then became the midday entertainment for those who were not out riding for the day. First check was of the carbs for water, in view of all the rain showers, but there was no problem there. Having once had a needle escape from its clip, this was checked with a finger up the bellmouth, except that at the rear the finger wouldn’t go in. On examination the choke slide was seen to be down – no wonder it ran badly! The handlebar choke lever, by contrast, was in its correct place, but a closer look revealed that the cable outer was not in its abutment. PUB almost never uses the chokes, leading to cables now being ‘set’ and a bit stiff, so that operating the lever is as likely to release the outer as it is to drop the slide. Presumably someone (not excluding the incompetent owner) had moved the lever and done this, the slide only slowly progressing downwards over the next few miles of vibration. At any rate, the problem was hopefully resolved (although the points were also checked just to be sure), and PUB’s embarrassment made public.
With the weather deteriorating, but supposedly less soon to east and south, a return back down the western A1/A1M was chosen again, although it would be a few miles extra. As it turned out it was slower too, mainly due to Sunday traffic on the A65. Nevertheless, there was no serious holdup, and the rain just about held off, so it made for a good run home, and 500 miles done over the weekend. Apart from that silly scare, a very rewarding trip.
Above right: This fairly fearsome looking ‘Versatiller’ is powered by one of the Vincent small two-stroke industrial engines. The Health & Safety brigade might have something to say if it was produced today!
Above: This alternative view of the Ribblehead viaduct does little to show its grandeur, but does illustrate its bleak location. This is how it would have been for the many Navvies who laboured mightily to build it (and of whom around 100 lost their...
In this rally view are some very rare Vincents. Foremost is a model PS, featuring a (Rudge) Python engine, to ‘Ulster’ spec. with a bronze head. Further back MV4433 is a similar, but less sporty, bike with an iron head. A rigid Wolverhampton built HRD...
Right: After completing the repair, PUB located this diagram of the ‘Watford’ speedometer in an old book. It might have helped – although as it only shows the speed measuring part and omits the mileometer and top bearing arrangement it would have been...
Below right: The centrifugal principle for speedometers is only met on a few vintage bikes, having been replaced by the Smiths chronometric, and then the magnetic type whose principle is illustrated here
Above: The Ribblehead viaduct, built by the Midland Railway in 1870 to 1874, is a magnificent piece of period architecture – and still in use (although its closure in 1980 was contemplated). Today it is a listed building and a tourist attraction,...
Top: Repaired Watford speedometer, working. Sorry about the fuzzy pic, but it was tricky holding the camera in one hand, the speedometer in the other hand, and operating a drill in the …er… other other hand!
Above: Just prior to journeying up to the Lake District, PUB suffered an almost flat tyre. Rather than risk it just being slow deflation from standing (and not checking before the ride), she fitted a new tube. In this shot can be seen the plastic...
In the absence of any 1/16” balls PUB bent up a piece of similar diameter wire into a ring – possibly for permanent use as the top bearing is lightly loaded, but in any case much easier for trial and error assemblies
Top: Mileometer wheels of the Watford speedometer, which show through holes in the face
Above: Speedometer mechanism (upside down in this view) is housed under the mileometer plate, and is operated by the inclined weight ‘flinging outwards’ towards the horizontal when the main spindle is spun. Unfortunately none of this is visible, or...
Above: One of the early Stevenage built VincentHRDs, this Rudge engined model features PCV’s original frame design, with its steering head to swinging fork pivot tubes (like a Seeley frame). Numerous modifications were introduced to improve its...
Below: Vintage Watford speedometer from a 1929 New Imperial. The barely visible bulge below the brass outer casing is where the centrifugal weight mechanism operates
Below: This rarity was not seen at the VOC rally, but at a more local meet. It is a series D Comet, of which only one was originally sold (a second 500cc was sold as the fully enclosed ‘Victor’ model in which form both were originally assembled). After...
Left: A surprising special seen at the VOC Annual Rally was this Shadow trike. Far from the opprobrium that might have been expected, it was met with great interest and congratulation for the owner (Glynn Baxter). No doubt many club members can...