Finally a very nice "period" picture of the TD1 motor.
The TD1A and B had crankcase mounted carburettors, the later TD1C had the floatchambers suspended from the top frame rail.
In order to improve carburetion many tricks were used. The irregular carburetion with the float chambers nearly a mile away...... was difficult to improve. Here a single float chamber is used, mounted between the carburettors, trying to balance the fuel feed bettrer.