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The motor-assisted bicycle known as the "Cykelaid" made its appearance at the Olympia Cycle and Motor Cycle Show in December 1920. The complete power unit was carried on a special front fork.
The Cykelaid could be purchased as a complete machine for £50. The specification included an Eadie coaster hub, rear hand-operated brake, number plate, rear stand and Brooks saddle. The wheels were 28"×1¾", shod with Dunlop Roadster tyres.
Alternatively, one could buy the complete front fork assembly for £32 and convert an existing bicycle. The early versions were not fitted with a front brake and, as mentioned above, the complete machine was fitted with two independent rear brakes. Presumably, when buying the front fork unit to convert an existing bicycle, one was also expected to fit an additional rear brake to the machine.
Within the next few years the specification of the Cykelaid had changed somewhat. The wheel size was reduced to 26"×2". Protection for the rider was improved by fitting deep valences to the mudguard and by lengthening the exhaust pipe. A front brake was now fitted.
The Cykelaid had a 105cc two-stroke engine rated at 1.25hp. Bore and stroke were both 51mm. A fuel tank mounted in front of the forks, across the top of the mudguard, fed an Amac carburettor. Ignition on the earlier models was provided by a chain-driven Runbaken magneto, mounted upside down below the crankcase. Later models had a flywheel magneto. The engine crankshaft passed through the front wheel hub so that, whilst the engine was on the left side of the forks, its flywheel was on the right. A small counter-shaft above the flywheel carried the clutch. Primary and secondary transmission were by chain, giving a gear ratio of 11:1.
Although the engine was lubricated by the petroil mixture, an additional oil tank was fitted. An oil pump driven by the front wheel hub delivered a measured supply of oil to the engine's main bearings. It would, therefore, be inadvisable to allow the engine to run for a long period with the clutch disengaged, since this would cut off the supply of oil to the crankshaft.
The engine unit increased the weight of a cycle by 35lb. It was claimed that it would propel a bicycle at speeds from 3mph to 20mph and that a 100 mile journey could be completed on a full tank of fuel.
One advantage of the Cykelaid was that it could be attached to tricycles and tandems as easily as to a solo bicycle.
Its manufacturer was the Sheppee Motor Company Limited of Thomas Street, York.
First published - Spring 1986
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