The MODERN MOTORCYCLE By "THE ROOK"
The MODERN MOTORCYCLE
By “THE ROOK.”
Some reflections on its reliability in the light of the behaviour of a selection of machines tested or owned by members of MOTOR SPORT staff during the last year.
MANY people are fond of proclaiming that the modern motorcycle is very nearly perfect and that it is only in detail refinements that there is any room for improvement. It is in answer to such as these that I am inspired to write this somewhat disordered account of some of the ailments which have occurred in the course of fairly ordinary running to certain machines which have been, or still are, in our possession.
From this article it must not be inferred that the road tests which occupy so much space each month are written to deceive. Far from it ! They are all written as accurately as possible and in an attempt to show up evenly the good and bad points of the machine in question.
However, it must be remembered that these machines when tested are new or at any rate in sound condition ; and they often remain in our possession for a fair time after testing. They are then put into ordinary use as hack machines with the variation of entering for an occasional local club trial or similar event, in fact they are put to just such service as many of our readers’ machines, which are used for all round purposes, and although driven hard are driven reasonably intelligently. Their good points are quite sufficiently crowed about by the gentry mentioned in the first paragraph, and it is with their faults that we are now concerned. It should here be made quite clear that no prizes are offered for discerning what makes are referred to, and that some of the machines mentioned are privately owned by members of the staff and have never been the subject of any previous criticism in this paper.
What we will refer to as machine A was a lightweight hotstuff sidecar outfit which was not in our possession long enough to test thoroughly the rate of wear of any parts of it, and it functioned admirably until it was almost due to be returned to the works when it very tactlessly broke its frame at the rear chain stays, thus blotting its copy-book and losing the full marks which would otherwise have been due to it. Machine B was a big twin likewise of the warm variety. This, while certainly having a terrific road performance, marred this performance by shattering the peace of the countryside by electing to hold a continuous competition between the exhaust and the overhead
valve gear, as to which could make the most noise. After a short time the exhaust stole a good lead by demolishing the silencer, splitting off a bit at a time. Not to be outdone the valve gear developed a hearty shriek to mingle with the clatter and in a final burst of enthusiasm a rocker seized, this in spite of a direct oil feed from a mechanical pump to the rocker box. The
pipe led to a union on the rocker box from which a hole was intended to be „drilled to the rocket bearing itself.
This hole had been totally omitted with the result that the oil was being fed into the solid metal, and although we know that the pores of metals are capable of secreting molecules of gas, it has not been found that lubricating oil will pass through them in any appreciable quantity !
This hardly shows a very high standard of workmanship or inspection during manufacture.
_ Machine C was a popular overhead valve lightweight machine which was chiefly remarkable for the fact that there was a bit too much emphasis on the lightweight and not quite enough attention to strength of working parts.
Early in its life it developed loud squeaks in the timing case and on investigation it was found that the cams and tappets were excessively worn. These parts were replaced (be it said very promptly and gratis) by the makers who expressed themselves” at a loss “to account for it. However, in a very short time the noise developed again and one day the squeak became so piercing and awe-inspiring that it was considered judicious to tow the machine home. Further examination proved that the first state of affairs had repeated itself, with extras, and it was actually necessary to clip the scale off the tappet feet, such was the temperature that had been attained.
This machine was one of the many now fitted with ” mechanical lubrication,” i.e., a mechanical device externally mounted on the engine in a nicely vulnerable position, which feeds oil into the crankcase. However, no steps had been taken to ensure that any of it was fed to any highly stressed bearings of working parts, and as a result the camshafts ran dry, though we have no doubt that they were intended to be lubricated by” oilmitt” that delightful term so much employed by the modern manufacturer to include the lubricaticm of anything for which no proper provision has been made. We are fully aware that genuine oil mist lubrication is highly efficient but the mist is no good without the oil. On this particular machine this trouble was overcome by suitable work with drills, unions, and piping and the
third set of timing gear functioned for some months without wear until the machine was disposed of. However, having cured this trouble we found the overhead rocker bushes wore out with great rapidity and required regular renewal at much too frequent intervals, the only means of lubrication being the almost prehistoric screwdown greaser.
Another trouble with this engine was that in a few months the little end bearing ‘showed signs of excessive wear and as the connecting rod had no bush, the ordinary methods could not be applied. The gudgeon pin and connecting rod were steels of similar hardness though not glass hard, i.e., the worst possible conditions for wear. As a result it was necessary to bore out rod and piston and fit an oversize pin, which process will have to be repeated every time wear occurs, and for the reasons mentioned above this will be often. No wonder so many people have a new machine every year. This machine also broke three rear wheel spindles in use no harder than that expected of a machine by any enthusiastic motorcyclist, and as it followed this up by breaking two fork spindles at short intervals (fortunately at low speeds in each case) it was considered wise to dispose of the machine without delay.
Machine D was another example of alleged value for money and while new was quite a pleasant machine though a trifle harsh, and with the usual clatter becoming so generally regarded as inseparable from the O.H.V. sports model. However, in a little over a month the machine presented an altered aspect and the opinions about it were not so complimentary.
The crude exhaust lifter ceased to function early in its life, which did not aid starting. In a few weeks top gear started jumping out ; a little later it would not even engage. A little hard work off the beaten track and the gearbox seized. Previous to this the enclosed kickstarter spring had broken, so the makers were informed and were only too pleased to hand out another gear box, in fact we were informed that their agents had ” service ” gearboxes in stock for this sort of contingency.
The steering was inclined to be treacherous until it was discovered that the forks had been sent out more or less solid. When they had been induced to work as spring forks the steering was quite O.K. The rear brake drum became distorted slightly and remained so, which made braking uneven though still adequate. The machine had electric lighting which functioned with some irregularity for a few weeks and then struck work altogether. Inside a month not one half of the total area of the tank remained covered with enamel, and finally the main bearing on the driving side having developed serious play, took to seizing intermittently and the machine is now in dock and likely to remain so for some time. It is nearly a year old and looks four times its age. Machine E was one of the nicest machines to handle we have tried but was marred by a continual succession of troubles which could nearly all be traced to an effort to produce a machine for about less than it should have been, and to a policy which included getting the machine eligible for the minimum tax. One of the first troubles was the now all too common one of a broken
kickstarter return spring. True, this was a small item and easy to replace, but it should never have occurred on a 1927 machine. For a week, i.e., during the running in period, all went well ; then when on a fairly urgent journey to fetch a part needed for another machine for a competition, a connecting rod parted near the little end, and on examination it was found that the little end bosses had been also parting from the rest of the piston, which doubtless hastened the trouble.
Again the maker’s service was tested and was found excellent and generous, though as will be seen this service evidently gained its efficiency by hard practice if our model was any criterion.
It must be admitted at once that this machine has been used extensively in trials by more than one rider, but nevertheless its mileage has not been excessive, and in view of the excellent performances put up in open trials by its brethren from the works many people would expect to be able to buy a standard model which would perform creditably in trials without a very great deal of special attention. Soon after the above episode the tanks started to give trouble and the machine has now had five new tanks, and one or two of these have been mended before being scrapped. In no case was any charge made but it naturally meant that the machine was out of commission. The chains were on the light side and wore at an incredible rate. The frame was also too light and whipped to such an extent on rough going that it was a very common experience for the chains to jump off the sprockets. Although the machine was seldom used two up, back wheel spokes broke repeatedly. At first they were repaired’ as soon as they broke but this became almost a daily task and the machine was usually ridden till 6 to 8 spokes were broken when they were replaced. No count was kept of the number used but in the first four months of its life at least enough spokes to build two complete wheels were used. At last it got such a nuisance that the wheel was dismantled and rebuilt with spokes several gauges larger than standard, since when no more trouble has been experienced. In less than a month the machine developed a whine on middle gear that completely drowned the not unhealthy exhaust note, and shortly afterwards the gear box became loose in the frame owing to the holding down bolts pulling out of the aluminium easing, and then the gearbox was returned to the makers who very graciously supplied another, which to date of writing this eulogy has given no trouble. One of the next troubles was a ” continual drying up, ending in intermittent seizures which called for investigation. This revealed badly damaged pistons and cylinders, and caused more correspondence with the factory. We were informed that we must have the engine converted to the latest type of lubrication (this was an early 1927 model) or the trouble would recur. Also they would replace the cylinders and pistons at half list price. This was done and although the engine ceased to dry up the oiling soon developed the fault that the sight feed would not empty into the engine from the sight feed except when the engine was stopped. . Thus the only method of lubricating the engine is to keep the sight feed full under pressure from the hand-pump. This method has the disadvantage
of being (a) very crude and (b) very messy, as the sight feed leaks oil over the tank. Clutch wires last on an average three weeks, which is annoying, as when in order the clutch is a very pleasant one.
Front brake wires also break too often (should they ever break ?) and the brakes have never worked with the power which should be easily obtainable from brakes of their size. The footrests refuse to remain rigid, will rattle about, and are very easily bent by any slight fall.
Bad misfiring and lack of power was noticed at one time and was traced to a worn camshaft bush which had also come loose in the crankcase. Owing to the fact that the bush was actually cast in the crankcase it was necessary to have a new crankcase. Again the makers “met us” on the price of this, but we had to do the work and the machine was some time out of commission. If any can point out to us the advantage of the above method of construction for this sort of job, we should be pleased to hear it. We fail to see it ourselves.
Not long ago the magneto ceased to give any spark and again the makers, this time of the instrument, were approached, who duly overhauled and repaired it. Very pleasant of them but very inconvenient for us. The steering head of this machine requires frequent adjustment and will shortly require new races. The carburation is anything but automatic, considerable ” tap-twiddling ” being required to get the best results. We can only hope that we had an unfortunate specimen and that next year’s model will profit by these troubles.
The next machine, which we will call F was only with us a short time and we were sorry to return it so soon. True it broke the kickstarter return spring, but otherwise it behaved well. It was from a factory famous for the soundness and reliability of its products and gave more signs of standing up to hard use than most we have had, and our only regret is that we were unable to prove this. It was a hotstuff 500 c.c. machine but combined smoothness with power. Machine was of similar type and confirmed the good impression of this class inspired by the other, though this machine was not free from the need of minor adjustments at short intervals. Both these last were more suited to sidecar than solo work on anything in the way of rough going.
H was a 350 O.H.V. which may be briefly dealt with as a good bicycle with an engine which would be vastly improved by a little racing experience. It was another short test machine and therefore gave no time to be worn out. However, all the valve springs were broken when handed back and the engine was remarkable for a certain ” period” in it. Most single cylinder engines have a “period,” i.e., a speed at which they vibrate. This engine had a special sort of ” period,” i.e., a speed at which it did not vibrate. In other respects the machine earned a high percentage of marks. The machine which conies last of this selection for comment, provoked several of us in turn to violence by its consistent refusal to break anything or even to call for adjustments. The only breakage that occurred the whole time it was in our hands was a fracture of the connecting link of the front chain. In our efforts to improve on this the machine was subjected to the most violent treatment in some of the roughest local scrambles
available, and owing to its remarkable steering it could be driven much faster over real rough stuff than any other machines mentioned in this article, and thus could be knocked about more. In spite of this, and of several pretty violent falls and absolute full bore driving on roads, not a single nut required tightening, nothing was ever adjusted, nor was any adjustment called for, nor was anything bent. Furthermore, and bitterest facts of all, this machine was a full year older than any other machine we are dealing with, the finish was as new, and the country of its origin was not G.B. Its first cost was slightly higher than the average machine of its class’ but surely reasonable quality is worth paying for, and it seems a pity that a country famous in the engineering world for the sound workmanship and long life of its products should have so many examples of cheeseparing in the one industry in which it now leads the world. True, the maker’s service is now good, but there is need for it, and we are afraid the fault lies in the present clamour for a machine of low first cost. Another few pounds on the price would in many of the cases mentioned in this article have obviated many of these troubles, which are a faithful record of Motor Sport’s stable for a period of twelve months. Perhaps we have been unlucky in our selection, but if we have, many others will have suffered similarly this year. May 1922 show more attention to detail reliability and less price cutting, and this may lead towards the ideal machine. It is still well beyond the horizon.
A Rover Novelty.
When the Motor Show opens a novelty will be seen in the new two-litre Rover” Six” saloon. Most motorists will have experienced the difficulty of backing down a lane or private drive at night and many will have scraped their cars against the bank or hedge. To prevent this, the Rover company has fitted a neat lamp at the rear of the body on the near side, pointing backwards. This is the same size as a side-lamp, but has a head lamp bulb and thus gives a powerful light, making a run backwards down a dark lane relatively simple. The lamp, which is controlled from the dash-board, can also be swivelled round to face front, when it is of great assistance in picking out the near side of the road during foggy weather.