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Archive indexOne of the more unusual cyclemotors which took part in the 1986 National Cyclemotor Run organised by the VMCC was a Mechanica Sinamec.
The Sinamec was first produced late in 1950 by the Mechanica company of Delft, Holland. It is a 34cc (36mm × 32mm) three-port two-stroke engine with a deflector-head piston. It mounts onto the front fork of a cycle and was sold as a unit complete with a wheel in either 26" or 28" sizes.
The cylinder and crankcase of the Sinamec are on the right-hand side of the wheel but the Novi flywheel magneto is on the left-hand side, on the other end of a crankshaft which passes right through the centre of the hub. A pinion on this crankshaft drive planetary gears which in turn mesh with teeth on the inside of the hub. To minimise wear some of the planetary gears were made of a fibre material and the other gears were made of chrome steel. A grease bath provided the lubrication for the transmission gearing.
The hub is in two parts and is carried on roller bearings. The outer shell, to which the spokes are attached, and the inner part, which is driven by the engine, are coupled together by a pin. This pin can be pulled out to disengage the engine, allowing the machine to be pedalled like a conventional bicycle.
The engine uses 20:1 petroil mixture delivered by an Italian Weber carburettor. The fuel is carried in a banana-shaped tank mounted above the wheel. It holds about a third of a gallon. Claimed fuel consumption is about 225mpg and the engine's 0.5bhp. output at 4,000rpm gives a Sinamec a top speed in the region of 16mph.
The exhaust silencer is mounted ahead of the engine and a long tail-pipe discharges the exhaust gases close to the road surface.
The usual handlebar controls of throttle and compressor are fitted. A 12 volt, 5 watt lighting set could be powered by lighting coils in the magneto.
First published - August 1986