The 1916 A.B.C. Motor Bicycle

A Machine of Much Genuine Originality

Genuine originality is very refreshing to a jaded journalist in days when most machines follow broadly accepted lines; the thrill of such novelties as the Scott and Douglas débuts is not a common experience. The A.B.C. machines occupy a unique position in that everybody is talking about them, whilst comparatively few people know them, since the factory is run on the system of a limited output of de luxe machines.

They are further unusual in that they outwardly bear some resemblance to several well-known makes, but that inwardly they bristle with striking and valuable innovations. As one of the few riders who have taken delivery of the latest model, I may be allowed to discourse on its merits under two heads, separating the technical and practical aspects.


I. - Technical.

The machine is built regardless of cost, and its war price is £75, which is steep for a 500 c.c. twin; but this policy enables the designer to realise engineering ideals in lieu of building down to a price, a consideration which hampers most commercial engineers. The engine is the heart of the machine, and the A.B.C. engine differs from every other engine - car or cycle - which I have ever sampled in that it combines the maximum of efficiency with the maximum of refined running. It can hiss like a snake at 2 m.p.h. or bellow like a bull at 65 m.p.h. The first feature is obtained by an extraordinarily excellent balance; if the engine is run throttled down with the clutch out, a hand, laid on any portion of the machine, will feel no vibration. The speed and revving capacities are probably shared by several other first-class engines, though I fancy the A.B.C. has the legs of most; and in this connection it must be remembered that its specification includes every weighty luxury imaginable, and its total weight is probably about 300 lb. The main feature of its revolution work is that it does not get tired. The second gear ratio of the four provided is 9½ to 1; I have driven it for ten consecutive miles on this gear as fast as the country roads near my house permitted, and it was perfectly fit and fresh at the finish; I do not know whether it is more remarkable that I could stand this, or that the engine could stand it. Two unusual points of design are mainly responsible. On the average engine both piston and cylinder are made of the same metal (cast iron); the piston gets the hotter of the two and expands more; seizure is always a possibility with such engines under maltreatment. But the A.B.C. has steel cylinders, and either aluminium or cast iron pistons. The cylinders always expand more than the pistons, and seizure is practically impossible, so long as an oil film is maintained. Compression is safeguarded by fitting an overhead exhaust valve on the top of the inlet valve, so that there is no " hot point " at one side of the cylinder barrel, and the tendency for piston or cylinder to warp, or expand in lop-sided fashion, is all but eliminated.

The technical knowledge and painstaking workmanship underlying these points are characteristic of the entire machine from stem to stern. The clutch, for example, is perfectly smooth in action, and is fitted with both hand and foot control, the leverage in both cases being so good that the little finger suffices to operate either lever or pedal. Both brakes go on as silkily as a spoon enters a tin of treacle; you cannot jam them, and the maximum power of the front brake is insufficient to lock the front wheel or upset the steering. The steering angle and balance are so designed that I can ride " hands off " at 45 m.p.h. Both cylinders can be detached, leaving the crank case in situ - an uncommon feature on horizontal twins; so can the magneto - but this point redounds rather to the discredit of other " flat " twins than to the honour of the A.B.C., as its arrangement is obvious. The gear box is made of phosphor bronze; many gear box troubles are ascribable to the shafts being mounted in less rigid materials. The gear lever is mounted at the best height and angle for convenient operation; four ratios - the maximum for practical purposes with a rigid drive - are provided, and the two higher gears, which often require interchanging at high road speeds, can be changed on the valve lifter, which is simpler than the use of the clutch. The chain drive is so adequately cushioned that it feels exactly like a belt in perfect condition; indeed, the machine can be driven with only one cylinder firing, full compression being retained in the idle cylinder without shock or jar being received via the transmission. The kick-starter is fully enclosed, and is dirtproof. An automatic carburetter is employed which give an approximately perfect mixture at all speeds, after the exhaust pipe, from which hot air is taken, is warmed up; in other words, after the first mile from a cold start. In actual practice, the mixture appears perfect after 300 yards, though there may be a tendency to choke under sudden accelerations for a mile on cold days. The frame is sprun fore and aft, without loss of lateral rigidity, and the springs deal indifferently with either horizontal, vertical, or compound shocks; yet they never bounce or clash. The handle-bar cannot loosen under sudden wrenches, e.g., in " scrapping " a hairpin bend with sidecar attached. The lubrication is mechanical and automatic, the rider's duty being limited to opening a tap on starting out, whilst a tilted sight feed glass informs him whether oil is actually feeding. The standard engine develops over 12 b.h.p. In other words, the machine embodies all the theoretic ideals which motor cyclists are prone to associate with the millennium.

 

II - Practical.

In actual riding it is difficult to imagine that the most critical purist could find any point to criticise, except the weight; and weight is naturally inseparable from a luxurious specification combined with substantial workmanship. Does a rider desire to travel slowly? He may climb the test hill at Brooklands at less than 3 m.p.h. without slipping his clutch, supposing he is an adept balancer. Does the user wish for a speed burst? He can do approximately 45 m.p.h. on second gear, 60 m.p.h. on third, and towards 70 m.p.h. on fourth. Does he prefer to potter at an even average of 25 m.p.h.? If he is a clever rider, he may maintain this pace exactly all day long irrespective of wind or gradient, as the machine will run steadily at this speed anywhere, if the correct gears and throttle opening be employed. Road vibration is as near as no matter non-existent. I made my tests over country roads, scarred all over with war potholes, and ridged by two deep ruts and a central hump. I failed to register any bumps up my backbone, and gentle bouncing was equally inconspicuous. The pistons never gum in the cylinders, and on frosty mornings, despite the temporary absence of a hot air supply for the carburetter, the engine started in response to one or two thrusts of the kick-starter without any priming.

 

 

Silent Gear Changes.

The novice at gear handling need never be afraid of the changing. Provided he declutches, he may change " up " from first to fourth with his engine doing 4,000 r.p.m. and the gears will go in silently; or he may change " down " from fourth to second at 30 m.p.h. with his throttle shut and again no noise will be heard. Car experts will pardonably regard these two statements as fictions, but they are none the less facts. I do not know why Mr. Bradshaw does not communicate the secrets of his gear change to car designers, or why car designers do not puzzle over the A.B.C. gear box, until their gears are as changeable as his; but the incredible facts are as stated. I have several times all but unsaddled myself with the jerk caused by experimental changes of this character, but I have yet to hear the gear teeth scrape, so that damage to gears through careless changing is likely to be nonexistent on the A.B.C.

In conclusion, I am well aware that the glowing claims which I now make for the A.B.C. will be taken with a grain of salt by my readers, but I think that as the machine becomes known riders will gradually be forced to admit that a machine of quite astounding intrinsic excellence has been added to our gallery of stars.

IXION.

From "The MotorCycle" - August 10th, 1916

 

 

 

The A.B.C. Bicycle.

I have been overwhelmed with letters about my article on the A.B.C., and have one small correction to make. The article was written some months ago, and the actual weight of the jigger was considerably overstated, partly because I came to it fresh from a baby two-stroke, partly because Mr. Bradshaw's typist struck a " 3 " instead of a " 2 " in writing to me on the subject. The weight is not more than that of the ordinary vertical single-cylinder 500 c.c. In reply to various correspondents, the machine is not capable of remarkably slow speeds on the fourth ratio; though it will tick over absurdly slowly in neutral, more slowly (I fancy) than any other engine would in normal adjustment, its power is attained by high engine revolutions, and there is not sufficient power at very low revolutions to permit the machine to run dead slow on a very high gear; I always change down to third gear for traffic work. I am hardly in a position to state what the normal petrol consumption should be, as I keep two or three bicycles running, and use the A.B.C. for speed work on good roads, or for fast climbing on freak roads. Still, I can get 70 m.p.g. under these conditions, and opine that a higher economy should be possible in steady riding on ordinary undulating roads. A further point is that the maximum speed obtainable on fourth gear is only possible when conditions allow the machine to be " whacked up." You cannot work, engine revolutions up to an abnormal figure on an abnormal gear except where conditions approximate to track work. The machine is fast because it can attain unusual speeds on second and third gears, rather than because its phenomenal fourth gear maximum can often be resorted to, and because the combination of high r.p.m., a variety of gear ratios, ami a terrific carburetter allow of ferocious acceleration. The " jump " when the engine is put on second gear and full throttle at the corner footing a single figure gradient is truly remarkable.

IXION.

From "The MotorCycle" - August 31st, 1916