Guide to Olympia, Nov 1921
Interesting features which should not be missed on the Allon exhibit are the horizontally split crank case and the method of casting in the oil leads. Cylinder and top half of crank case are cast together, and the engine unit is held in the frame by lugs placed above the crankshaft centre, so that it is only necessary to detach the lower half of the crank case in order to remove the crankshaft, connecting rod, and piston.
A large bore steel oil pipe leading to each crankshaft bearing is cast into the crank case so that only one oil union is necessary and a multiplicity of bent tubes is avoided. Larger bearings have been fitted, and the piston has been modified to obtain lighter weight and better gas flow.
Several detail modifications are incorporated, including wider mudguards and longer wheelbase. A Villiers flywheel magneto is now fitted, thus avoiding an auxiliary chain drive which might cause noise. This ignition set may be converted to provide current for lighting at a very moderate cost. Sensible legshields are included in the specification, and an unusual feature is the fitting of the Allon special band brakes to both front and rear wheels.