SPORTING MACHINES ON TEST.

SPORTING MACHINES ON TEST.

The 4-valve Sports Rudge-Whitworth.

By “THE

RABBIT.”

I T is with very mixed feelings that we attempt to record our impressions of the Sports Rudge ; sometimes we feel disposed to being thoroughly rude, sometimes to being glowingly fulsome in. our praise of the machine. This paradoxical state of affairs is due largely to temper and moods. There are times when any motorcycle is anathema to the writer, whether it be the best or the worst machine in the world ; at other times even the sorriest of crocks seems possessed of at least a few virtues. Having had the Rudge in our possession for several weeks we naturally experienced all these moods, and

crashes were carefully investigated ; neither road was unduly bumpy ; one rider was doing a mere 30 m.p.h. and had both hands on the bars ; the other rider was changing gear from 3rd to top at about 50 m.p.h. when disaster overtook him. The only light thrown on the matter was that both riders admitted that they were not holding on particularly tightly, so that a slight bump, combined in the one case with the gear changing operation, upset the balance of riders and machine and wrenched the bars out of their grasp. It speaks volumes for the machine that these two crashes did no more than damage the lamp stays,

strange as it may sound, the Rudge actually seemed to pass through different phases of behaviour too. This was not merely a question of something becoming out of adjustment and then being readjusted. Deeper issues than mere engine performance were concerned, as will be seen. The writer himself would have said that the machine steered very well at all speeds on reasonably good surfaces, and was quite manageable at speed over bumps— yet, amazing fact,—two different and thoroughly experienced riders were thrown heavily after experiencing full lock-to-lock wobbles. The circumstances of both footrest and front number plate, although we measured, that in the 50 m.p.h. episode, the Rudge rolled and slid for a genuine 60 yards before coming to rest in the hedge. Nothing vital was bent or broken, and the steering was not affected. As mentioned above, the writer had no trouble with the steering of the machine, probably because, being of a timid nature he invariably and almost unconsciously holds the bars somewhat more tightly than his more care-free and dashing acquaintances. He was at no time aware of any undue fatigue or strain through riding the machine for long distances as fast as circumstances permitted, and at no.time did the machine

attempt to get out of hand.

In connection with the steering we must mention a small criticism ; in the event of the machine becoming at all restive on a bumpy road, the rather dropped handlebars do not permit of a comfortable position consistent with the extra control necessary on any motorcycle under these circumstances. These bars would be suitable for track racing in conjunction with a rearward saddle position, but for fast road work with the standard saddle, a flatter and higher bar would be better. Another way in which the Rudge seemed capricious (apart from its playful throwing of riders) was in slow running. At times it had the most gentlemanly tick-over and ran most sweetly on a high gear at low speeds ; without any alterations, at other times it would not run slowly at all, misfired and knocked painfully when pulling slowly on small throttle openings. An interesting fact that came to light with regard to this matter was that Power Petrol seemed to give by far the best results, eliminating the knocking to which most high compression engines are addicted when suddenly accelerated, and giving much sweeter running at low speeds.

Benzol mixture gave almost equally good results but the compression ratio, even with the reducing plate under the cylinder is too high for comfortable running on ” straight” petrol.

Let us now turn to the description of some of the machine’s virtues, and it had many ; during the course of a month we used it as an all weather runabout, not sparing it in any way and never cleaning or adjusting anything. At the end of this period, when the machine was excavated it was found that two small bolts (mudguard stay and silencer) had been shed, the front chain needed adjustment and the tappets could just be taken up very slightly. We considered this very creditable in view of the constant state of filth in which the machine was run, the rough roads and farm tracks covered, and of course the two crashes. There appeared to be no positive method of shifting the gearbox to adjust the chain ; a pity, as a simple drawbolt mechanism is very easy to arrange. The chief virtues of the machine, however, come mainly under three headings, (1) Reliability, which we have

already dealt with, as apart from the points mentioned above no tools were needed or used. (2) Economy, and (3) road holding under slippery conditions.

With regard to economy, on a long fast run, using Power Petrol or Benzol mixture, the consumption of fuel was at the rate of roughly 90 m.p.g., while the mechanical pump supplied adequate lubrication to the engine at the rate of a gallon for every 800 miles. These figures are very creditable when it is considered that the Rudge is a heavy and powerful machine and was driven fairly hard all the time.

We can safely say without exaggeration that we have never felt more safe on greasy corners than when we were astride the Rudge ; it was possible to completely ignore mud and wet and to bank the machine as far as the footrests permitted (not quite far enough for really fast work) without fear of a skid. In addition to this it was possible to brake hard with certainty and safety on all conditions of road surface without provoking a side slip ; at the same time both brakes were extremely powerful when worked independently, though with the patent interconnecting system, the front brake did not seem to do its fair share of work.

The Rudge sports silencing system employs two long exhaust pipes with cast aluminium expansion chambers, slung from the chain stays, from which the gases escape through drilled and flattened tail pipes ; the resulting note was deep and pleasant and by no means unpleasant to the most jaundiced motorphobe. Mechanical silence was good except for a slight noise from the overhead valve gear and a worse noise when the chains became slack ! With regard to maximum speed, in standard tune, with compression plate in, we do not think the Rudge was capable of very much more than 70 m.p.h. ; we always felt that top gear was somewhat on the high side, since the engine seemed to revel in 3rd gear work. On this gear, which was not particularly high, nearly 60 m.p.h. seemed possible. We did not time the Rudge for maxi mum speed, the above figures are merely guess work, and it is quite possible fhat the high top gear led us to underestimate the maximum speed attained. The only definite information we can give concerns a run of 98

miles in the Eastern and Home counties, on a day when the roads were peculiarly greasy and when a strong wind blew in our face for a large proportion of the journey. This journey, including a thoroughly sedate negotiation of at least ten towns and villages was covered at an average speed of 38 m.p.h. Anyone who knows the road between Kings Lynn and Cambridge, with its serpentine corners, its own special brand of grease, and the howling wind of the fens, will realise that the Rudge must have been travelling fairly well on the straight at times, besides being remarkably stable on the innumerable slimy bends. Starting was always certain with about two kicks, though a certain amount of strength was necessary. The exhaust lifter was not used as it was inclined to stick ; the engine was therefore rotated backwards until it came up against compression and then bounced over by the kickstarter. In spite of a fully retarded ignition lever, considerable energy was necessary to prevent a savage back-fire. The Senspray carburettor fitted to the Rudge seemed to be an altogether admirable instrument, functioning well throughout the range of throttle movement. This latter by the way was rather excessive ; in the all out position it was extremely difficult to reach the throttle lever to shut off ! In other respects the riding and driving comfort was distinctly good, as a result of a good saddle, light clutch and accessible brake controls. The method of gear operation dispenses entirely with the normal tank gate or rack, the positions being indicated by numbers on the tank. At first this proved troublesome, but once we discovered that a far easier change up could be made if the throttle was not closed, gear changing became a pleasure. The change between the two intermediate

gears was delightfully easy, but a little more care was needed in engaging the two extreme ratios ; although we personally felt quite at home without the gate, we itn-. agine that many riders would appreciate a more positive method of locating the lever.

In conclusion let us remind readers that in spite of its thoroughly comprehensive specification the sports Rudge sells at the extremely modest figure of £56, while an extremely cheap and efficient electric lighting set is included in the Rudge-Whitworth equipment, nor must it be forgotten that during 1926 the few racing Rudges having performed with great reliability in the T.T., Ulster Grand Prix, Belgian Grand Prix and other important events, several times running among the first three at the finish, and always showing a useful turn of speed.