Gnome-Rhone Motorcycles

Today in Motorcycle History

Gnome & Rhone Motorcycles 1922-1923


Big Output Foreshadowed of new Gnome and Rhone Three-speed Outside Flywheel Double Purpose Machine.

Of trim and symmetrical appearance, the 499 c.c. Gnome and Rhone as seen from both the valve and flywheel side. In future models a silencer will be fitted.

MAINLY following standard lines, but possessing several attractive features, the Gnome and Rhone is about to appear in the British market. This machine was first described in our report of the Paris Show last year, but since that date it has undergone a good many improvements.

Though of French construction, being built at the famous Gnome and Rhone works which turned out 30,000 aeroplane engines during the war, the 499 c.c. Gnome and Rhone was designed by an Englishman, J.J. K. Bartlett, who has distinguished himself in French competitions on both this machine and the A.B.C. (which is also the company's production), he competed in the Tour de France of 2,300 miles on the machine under review without the loss of a single mark.


Gnome-Rhone 500cc 1922

The Gnome-Rhone, a machine which conforms to British ideas of clean design and finish. The engine has an outside flywheel and the gear fitted is a Sturmey-Archer three-speed.

Designed for Cool Running.

A 499 c.c. single-cylinder air-cooled engine, of 85 x 88 mm. bore and stroke, with outside flywheel, provides the motive power. The whole of the interior of the cylinder is machined, and the radiating fins are especially deep, particularly round the exhaust port, while there is an ample air passage round the valve chest. There are no separate valve guides, these being cast integrally with the cylinder.

In the timing gear a single camshaft is employed. Double roller bearings are provided to the connecting rod, and there is a double row ball bearing for the main shaft on the transmission side.

It is worthy of mention that the method of securing the gudgeon pin by means of two spring rings fitted in grooves in the latter and engaging with corresponding grooves in the piston boss renders it safe and yet easy to detach.

Easy Starting Air Strangler.

Mixture is supplied by a simple single lever Gnome and Rhone carburetter provided with a strangler to the main air intake, thus ensuring easy starting under all conditions. The air inlet is cone-shaped, and is carried well to the rear of the carburetter.

Transmission is by chain and belt, a Sturmey-Archer three-speed gear box being employed. The primary drive is " outside " the flywheel and is enclosed in a sheet metal case.

Two Foot-controlled Brakes.

Originality is shown in the design of the brakes. One of these, of the direct-acting variety, is controlled by the rider's left heel, and consists of a large shoe applied to the belt rim, while the other is actuated by the rider's toe, and is applied directly to the periphery of the flywheel, the pedal being on the offside footboard; Good spring forks are employed, and caps are provided to keep wet and grit from the hubs.

In the first model seen over here the magneto is controlled by a lever on the tank, but in future models this will be handlebar-controlled. It is interesting to note that all control wires are concealed and pass through the handlebars, and that sidecar lugs are incorporated in the frame.

Extensive Production Programme.

The Gnome and Rhone is to be made on mass production lines, 10,000 machines being suggested for next year and 20,000 the year after ; the first batch is practically ready for delivery. It is hoped to produce the machine at an extremely moderate price. English concessionnaires have not yet been appointed, but the export of the machine is handled by Overseas Sales, Ltd., 21, George Street, Hanover Square, London, W.l.

The Motor Cycle, September 7th, 1922.

The 1922 Olympia Show.


An Anglo-French Product.

4 H.P. Model.

85x88 mm. (499 c.c); single cyl. four-stroke; side valves; hand pump lubrication; own carburetter; chain-driven mag.; 3-sp. gear; clutch and kick-starter; chain and belt drive: 26x2¼in. tyres. Price, £69.

OVERSEAS SALES, Ltd., 21, George Street. Hanover Square, London, W.1.

Designed by an Englishman, but made in France, the Gnome-Rhone is more interesting because of the intention to manufacture it on mass-production lines (10,000-20,000 per annum is the suggested output) than for any unconventionalities in its construction. Indeed, although nearly the whole of the vital parts of the machine are produced in the huge Gnome-Rhone aeroplane factory (excepting the magneto), the layout and design generally are on the very simplest and most straightforward lines. Except the bottom bracket, all the frame lugs are drop forgings.

The engine, which has a ball-bearing big end and a ball-bearing mainshaft (transmission side), has an external flywheel with the primary sprocket on the outside. Thus it has been easy to enclose the primary chain in a neat case. Valve ports have been designed to give an easy flow to the gases.

Other items worthy of inspection are the long pedal-operated direct-acting rear brake, the flywheel brake, and the air strangler to facilitate starting. Foot-boards and fairly adequate mudguards are fitted to all the models shown, and to one model a simple spring wheel side-car with an English body is attached.

Olympia Show 1922
The Motor Cycle, November 30th, 1922. Page 835