Motorised Bicycles

Gallery opened 2 Feb 2023

Page updated: 22 Mar 2023

HMW-Fuchs motorised bike added
More on Avaros added


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Here we deal not with motorbikes as such, but motorised bicycles, which typically have a small engine (very often a later addition) driving the front or rear wheel of a more-or-less standard bicycle frame. Motorwheels, (also called cyclemotors) which often used 2-Stroke engines, were notoriously unreliable. Basic servicing was sometimes required even if they were left unused for only a few weeks.

The engines, often only 35cc or less, had little power and on even a gentle hill you would have to resort to a bit of LPA. LPA (Light Pedal Assistance) was a discreet way to refer to the need to do quite a lot of pedalling. A major problem was that it was very difficult to incorporate a gearbox, so often the engine would be running at non-optimal rpm.

Engines were applied to either the front or rear wheels. Putting the engine on the front wheel, often just in front of the handebars, made the steering heavy, but it did mean all the engine controls were right to hand. But... most of the weight of a bicycle and rider is on the rear wheel, so you might expect much better traction. Despite this, there were many designs with front-wheel drive, the VeloSolex being the best-known example.

Ignition was (always, as far as I can tell at present) by magneto, so there was no need to carry a battery. It was usually a flywheel magneto to save space.

Many (all?) of these engines had a device called an exhaust valve lifter or decompressor; which may sound obscure today. It was a control on the handlebars that opened the exhaust valve no matter what the position of the exhaust cam. This prevented any compression in the engine to make push starting the engine easier, because there was no clutch to disengage. It could also also be used to rather crudely reduce engine power to slow down. To stop you had to keep the lever open until the engine stalled. To someone used to a clutch this all sounds rather unsatisfactory.

There is also the question of transmitting the engine power to the wheel. This might be by gearing, (eg Smith Motorwheel) by chains, (eg BSA Winged Wheel) or by friction roller onto the tyre. This might be one roller bearing down from above, or two rollers gripping either side of the tyre. The obvious snag is that the tyre will carry up water and mud from the road and compromise the friction drive. The machines with a roller on top of the wheel often had a lever that lifted the roller and gave the effect of a clutch.

Left: The Werner Motocyclette: 1898

This is really a motorbike rather than a motorised bicycle, even though it looks like the latter. It had a 198cc engine, much larger than those used later in motorwheels; this probably reflects the immature engine technology of the time.

Paris-based Michel and Eugene Werner had built their first motorcycle in 1896 by the simple expedient of mounting a single-cylinder petrol engine, designed by Hippolyte Labitte, in front of the steering head of a bicycle, directly above the front wheel, which it drove via a belt. Belts in this sort of situation are notorious for slipping.

It is famous as one of the first practical motorcycles, and proved an immediate success. The Werner brothers abandoned their existing cinematograph business to set up a factory to build it. Notorious entrepreneur Harry J Lawson, owner of the Motor Manufacturing Company (MMC), acquired the British rights to the design, which was built at his Motor Mills plant in Coventry. In 1900 Werner sold a staggering 1,000 units but by this time Lawson had found it more expedient to have the French factory supply him with complete machines.

Left: The Smith motorwheel: 1910

This is the only configuration so far known where you didn't just add an engine- you got an extra wheel as well. There would seem to be an obvious snag in that the weight at the rear of the bicycle was now split between two wheels, which I would have thought made the traction uncertain. However, the Smith motorwheel was popular.

The Smith Motor Wheel was an ingenious design. The disc wheel was driven directly from the cam-shaft, which was geared down 1:8 from the crankshaft to give a suitable drive ratio. However it was a 4-stroke engine and the camshaft of a 4-stroke engine must rotate at half engine-speed; Smith got round this by having four lobes rather than one on the camshaft, so it was effectively turning at half engine-speed.

This ingenious idea was borrowed from the Wall Motor Wheel, invented in England in 1910, of which Smith had bought the US manufacturing rights. The Wall Motor Wheel used a 4:1 reduction ratio and a two-lobed exhaust cam; the inlet valve was automatic.

Left: The Smith motorwheel: 1910

This is a different and unrestored example, believed to date from 1918. The bar in front of the flywheel looks as if it was a (not very effective) safety guard for the flywheel rather than a structural member.

There is much more information on the Smith motorwheel in the N-wheeled car gallery of the Museum.

Left: The Auto-Ped: 1916

This was the caption when the picture was originally published:

"Lady Florence Norman, a suffragette, on her motor-scooter in 1916, travelling to work at offices in London where she was a supervisor. The scooter was a birthday present from her husband, the journalist and Liberal politician Sir Henry Norman."

Not perhaqps a motorised bicycle, but the front-wheel drive intrigues me.

Left: The Auto-Ped: 1916

A contemporary description:

"The engine is geared to the front wheel via a disk clutch. The flywheel, on the right side of the front wheel, contains a 6-volt lighting generator that originally furnished current for lighting and ignition, but the system later was altered by the addition of an ignition coil and four dry-cell batteries. The ignition switch is mounted on the right side of the frame, and the gasoline tank is above the front fender. All control of the vehicle is through the steering column. Turning the column steers the machine in the conventional manner; pushing it forward engages the clutch; and pulling it back operates the internal, expanding brake on the front wheel. Turning the left grip operates the throttle, and turning the right grip operates the compression release through a wire controlling the opening and closing of the intake valve. A hand Klaxon is mounted on the left grip."

I am a little uneasy about declutching by pushing the steering column forwards.

Left: The ABC Skootamota: 1919

I know this isn't a cyclemotor per se, but it certainly looks like one.

The ABC Skootamota was designed Granville Bradshaw, a man with a reputation for wayward inventions like the Omega toroidal engine. There were earlier designs for aircraft engines and so on that failed to reach expectations. However, it appears that Mr Bradshaw got it right this time, and the Skootamota was very successful. One reason was its flat floor, which allowed ladies to ride it in the costume of the period ie skirts or dresses.

The single-cylinder four-stroke engine had a capacity of 123cc (60x44 mm) and deveoped 1.5 HP; it drove the rear wheel via the camshaft (for the 1:2 reduction ratio) and then a chain in a case running in an oil-bath; ther was no gearbox and apparently no clutch. The Amac carburettor was gravity fed from the fuel tank above it. Early engines were exhaust-over-intake but later versions had two valves. It was fitted with 16x2 3/8in. Clincher tyres.

There is more information here.

Left: French ad for the ABC Skootamota: 1919

The Skootamota was manufactured and sold by Gilbert Campling Ltd of under a license from Mr Bradshaw. It was sold in Britain and throughout Europe.

From the ad we learn that maximum speed was 30 km/hr (18 mph) and was allegedly capable of climbing a 1 in 10 hill. There was of course no way to add pedal assistance, as on true cyclemotor machines.

The Skootamota is considered the fore-runner of all motor-scooters. It was so successful that it inspired a huge number of copycat competing machines, and the competition was so fierce that production only ran from 1919 to 1922. It is an unfair world.

There is more information here.

Left: The ABC Skootamota: 1919

"THE A.B.C. Skootamota is the only exhibit at this stand. Two commercial types are shown, haying a box for parcels fitted in place of the usual seat. A spring saddle being attached direct to the top of this. A tropical model is also shown, enamelled in light colours, and fitted with a canopy. Three standard models are exhibited, one of which is nickel-plated all over. As is well known, this scooter is fitted with a small four-stroke engine of 124 c.c. The cylinder is placed horizontally over the back wheel, and is fitted with a detachable head, while the transmission is direct by chain to the back wheel. The valves are both located in the head, the inlet valve being at the side and the exhaust valve overhead. The power is transmitted through the camshaft, which allows of a sufficiently low gear being obtained without the use of sprockets of undue size, the wheels being 16 ins. by 2½ ins."

Source of text: Motor Cycling 26 November 1919. Article on the 1919 Olympia show

The picture shows an exhaust valve lifting lever, and there is no mention of a clutch.

There is more information here.

Left: The ABC Skootamota: 1919

The other side of the Skootamota; the bottom of the chain-case is missing.

"Designed by Mr. Granville Bradshaw, the Skootamota is full of ingenious points. It is interesting to note that its cylinder forms half the unit of the neat little flat-twin stationary engine which Mr. Bradshaw designed for electrical generating sets and blowers for filling airships during the war. Following the original A.B.C. practice, the exhaust valve is situated in the cylinder head, which is detachable, and the inlet valve beneath it, while the cylinder is of steel, and is turned from the solid. One of the features of the Skootamota is that it is built as a miniature motor bicycle. The power unit is extremely neatly designed, and the transmission to the rear wheel is by a protected chain. The designer did not intend that the scooterist should stand, and the Skootamota is equipped with a comfortable pan seat. A novelty on this stand is a Skootamota equipped as a miniature tradesman's carrier, bearing the name of Messrs. Harrods, Ltd., and in this capacity it is possible that these little vehicles may prove to be extremely handy for the delivery of small parcels. Another scooter carrier shown is built for Messrs. Morel Bros. One Skootamota has a plated finish, and yet another is provided with a canopy for use in tropical countries."

Source of text: The MotorCycle 27th November 1919. Article on the 1919 Olympia show

Left: Motorised bike using a Labinal engine: 1922

The Labinal company manufactured auxiliary motors in Paris, for attachment to bicycles. The first Labinal Micromoteurs appeared in 1922; production ended in 1928. The 2-stroke engines had a capacity from 38cc to 50cc; one version (it is not clear which) gave 0.75 HP at 3500rpm. Drive was by a roller onto the front tyre.

There is more information here.

Left: Technical details of the Labinal micromoteur: 1922

A good deal of information here. I plan a translation but for the moment you will have to use Google Translate.

Left: Velosolex bicycle/moped: date unknown

The French Solex company were a major manufacturer of carburettors; they also made the Velosolex machines. The engine is an integral part of the bike. The engine installation is very neat. They were extremely popular in France, and in total 8 millionwere sold in Europe. The Solex brand is now owned by Magneti Marelli.

Left: Velosolex bicycle/moped: date unknown

The Vélosolex used a 49 cc motor mounted above the front wheel. Drive a small ceramic roller that rests on the tyre. The first prototype VeloSolex was built in 1941, presumably intended as a response to petrol shortages in France during WW2. The motor was applied to standard bicycles such as the “Alcyon” brand, being initially by a 45 cc engine developed by Solex. VELOSOLEX were produced commercially from 1946 with a 45 cc engine without clutch, then later with a 49 cc engine.

There is more information here.

Left: The Peugeot Motocyclo: 1922

Another of the rare machines with the motor fitted on the axle of the front wheel.

Left: The Fichtel & Sachs Saxonette: 1938

The Fichtel & Sachs Saxonette motorwheel appeared in Germany in 1938; it was considered an improvement on previous designs and is regarded as the forerunner of the post-WW2 motorwheels, but had its problems and production ceased in 1939. It had a relatively large 60cc 2-stroke engine with a flywheel magneto.

After the end of WW2 engineers at DKW copied and improved the Saxonette to create the Radmeister project; this was a starting point the for British Cyclemaster engine.

Left: The Fichtel & Sachs Saxonette: 1938

The Fichtel & Sachs Saxonette motorwheel appeared in Germany in 1938; it was considered an improvement on previous designs and is regarded as the forerunner of the post-WW2 motorwheels, but had its problems and production ceased in 1939. It had a relatively large 60cc 2-stroke engine.

After the end of WW2 engineers at DKW copied and improved the Saxonette to create the Radmeister project; this was a starting point the for British Cyclemaster engine.

Left: BSA motorised bike: 19??

The BSA Winged Wheel was one of the most popular motorwheels in Britain; from its introduction in 1953 until 1957. It was a package of engine and rear wheel that weighed about 27 pounds.

Note the petrol tank on top of the rear mudguard. This held half-a-gallon; according to the manufacturer's figures that would take you 100 miles. Seems a bit optimistic...

Left: BSA motorised bike: 19

The most popular of all the cyclemotor cycles in Britain was the BSA, primarily intended for mounting the BSA Winged Wheel engine. It was sold as a complete machine with a Winged Wheel factory-fitted, but could also be bought with no a rear wheel "for use with Motorised Wheels of all types".

The advertising blurb make a point of the fact that there is a positive drive by chain, rather than a slippery friction roller.

Note the need to give "slight assistance on the steeper hills."

Left: BSA Winged Wheel: 1953

The Winged Wheel had a single cylinder of 35cc with 36mm bore and 34mm stroke; BSA claiming one horsepower at 6,000 rpm, which is pretty fast rotation for the era. The cylinder had horizontal finning. Drive was by gears to the axle. There was a friction clutch but no gearbox.

The circular brake drum with its single internal shoe (which was considered by commentators to be very effective) is an integral part of the rear wheel. No adaptions to your own rear wheel possible here.

Left: BSA Winged Wheel section: 1953

This drawing only shows part of the wheel; the axle is indicated by the red lines.

BSA sold its bicycle business to Raleigh company in 1957, and production of the Winged Wheel ceased. An impressive 29,000 units were sold; less than 300 are known to survive today.

There is more information here, and here

Left: Lohmann compression-ignition motor: 1952

The Lohman cyclemotor was an unusual 2-stroke compression-ignition German design meant to run on paraffin; it had variable compression controlled by a twistgrip. It was mounted beneath the chainwheel of a bicycle. Drive was by a rubber wheel pressing on the underneath of the tyre. Most roller-drive cyclemotors had the roller on top of the tyre.

It was claimed that the Lohman could achieve 350 miles per gallon, but as far as is known this was never proven.

There is more information here.

Left: Lohmann compression-ignition motor: 1952

Although the motor was designed to run on paraffin, though it was sometimes described as a diesel engine; apparently in practice a carefully-judged mixture of diesel, petrol, and paraffin, plus 2-stroke lubricating oil, is required to make it work reasonably today. This suggests that customers would have been faced with some serious problems.

Note the claim that there was no need to pedal on 1 in 8 gradient; this seems very optimistic to me. Howver judging by the top left picture on the leaflet, you do have to carry it up stairs. The middle picture shows a man towing a trailer and with a front carrier on the bike. I don't think you're going to be sailing up 1 in 8 hills wth that equipage; I'm not sure it would be much use on the level.

There is more information here.

Left: Lohmann compression-ignition motor: 1952

The power output is here stated as 75 BHP at 6000 rpm, truly impressive for 18cc; it must be a misprint for 0.75 BHP. The Lohman was imported by Britax in 1952 and 1953; quite a short time, and it seems likely it was not very popular.

There is more information here.

Left: VeloVap motorised bike: 1959

Here the engine is an integral part of the bike. Note small petrol tank behind the saddle. Presumably a pipe ran forward to the engine through the central tube.

Left: 1951 Avaros Ideal Servo-matic de Luxe motorised bike: 1951

Another engine over the front wheel. What (if anything) Servo-matic meant is currently unclear. Drive was probably by friction roller. A neat installation.

Note ignition cable running over the mudguard to the flywheel magneto on the other side. Looks like the cable has become detached from the sparkplug.

Left: 1951 Avaros Ideal Servo-matic de Luxe motorised bike: 1951

Left: 1951 Avaros Ideal Servo-matic de Luxe motorised bike: 1951

Left: HMW-Fuchs motorised bike: 1953

This Fuchs motorwheel/cyclemotor is a attached to a restored Austrian HMW bicycle. The motorwheel was made by the same company, so the engine was very likely attached at the factory.

Note the logo on the engine- 'Fuchs' is German for fox. The engine was called a Hilfsmotor, ("help-motor") indicating it was only capable of doing part of the work of moving the bicycle. Some LPA required...

There is more information here. The site says the bicycle is from 1949, while the engine dates from 1953, which suggests it was in fact an aftermarket attachment.

Left: HMW-Fuchs motorised bike: 1953

A view of the complete motorised bike.

There is an excellent selection of motorised bicycles and mopeds (there is a very blurred line between them) at

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