A MACHINE which embodies many interesting features, all of which are mechanically excellent, is the new sporting model Diamond manufactured by Dorsett, Ford and Mee, of Sedgley Street, Wolverhampton. Our readers will recall that the salient features of the Diamond machine are the extremely large valves (the inlet being overhead), the unusual double bevel two-speed gear, and the sloping top tube. All these features are retained, but modifications have been made in a few places.
The sporting type has a somewhat altered cylinder, vertical ribs being cast at an angle across the head. The sparking plug is now placed horizontally in the side of the valve chamber, and the inlet pipe is curved away so as to be well clear of the frame, and to allow easy access to the valve. The bore and stroke of the engine are 75 x 70 mm. Both inlet and exhaust valves provide a clear port of 1¾ in diameter.
Engine and Frame Modifications. The only other alteration to the engine is a somewhat improved crank pin fixing, and the gear remains as before. The latter s particularly simple in action, as by the removal of a single cover plate it is possible to examine both gears, the clutch, camshaft, and magneto drive.
The frame is slightly altered, the pronounced slope to the top tube having been modified, and though the straight tube till remains, the actual seat-pillar lug is cast with a slight curve in it, consequently, the effect of dropped tube is obtained without any bends being formed in the actual tube. It will be remembered that the Diamond was one of the very earliest machines to be fitted with all straight tubes and a sloping top rail.
The sporting model has no kick starter. It is fitted with a long silencer pipe, with a small expansion chamber close to the rear end.
The standard model will-in future be fitted with somewhat wider guards and a hinged footrest, which leaves plenty of room for the kick starter pedal.
Commendable Kick Starter Design.
The kick starter itself is worthy of attention, as it acts direct on the crankshaft through one pair of gear wheels only, consequently there is no intermediate transmission to cause stiffness. The clutch remains as before, consisting, as it does, of a double metal cone running in oil. The fittings throughout are excellent, and include drip feed lubricator, a pan seat, and a stout stand and carrier.
From a short run on one of the sporting models we may safely say that we have seldom ridden a machine of the same capacity winch has more life than the Diamond. It might be thought that the bevel and chain drive would produce considerable noise, but this is not the case, and the gearing was almost equally quiet on both low and high gear. The riding position is comfortable and the speed is surprising from which it will be gathered that our impressions were favorable.
The Motor Cycle, November 19th, 1914. p553.
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