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.