Our thanks to Ben Ludolphy who has kindly sent in details of the BHS machine.
This machine was apparently made around 1980/81 by Australian Bob Humphreys, who at that time was the skipper at Milton Keynes Speedway. As you can see, there are only a few tubes used for the frame, and in addition to the frame modifications, Humphreys has lowered the Weslake OHV 4V engine and moved it further back in the frame.
The oil tank has been moved to the front of the engine, and the fuel tank has been moved to the centre of the machine to bring the center of gravity down further in an effort to give more drive on the slick tracks of that time.
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