Rudge

Rudge 500 Ulster 1928

Only rarely has a motorcycle manufacturer who has limited himself to one type of engine gone down in history. This is the case with Rudge, however, perhaps the most famous motorcycle builder of the heroic age of motorcycle racing. The Rudge single-cylinder four-valve engine, built in 250-cc, 350-cc, and 500-cc. versions, won a host of victories. The first four-valve Rudge was a 500-cc. version built about 1925. It entered the most important races of the time on an experimental basis but was not a great success, because the general structure of the vehicle was not on the same level as the engine.

In 1928 the Rudge 500 was given a new look. It now boasted a good chassis, large-diameter drum brakes, and an even finer engine. Graham Walker rode this motorcycle to its first win at the Ulster track and lost the 1928 Senior Tourist Trophy only because of a banal accident.

Two years later the Rudge 500 reached the peak of its career. It won all the major European races in 1930, including the European Grand Prix. (Rudge also won in the 350 class.) In that year's Senior Tourist Trophy Rudge came in first and second. In the Junior Tourist Trophy Rudge motorcycles took the first three places. Rudge lost in the higher classes in 1931, but the new 250 triumphed at the Tourist Trophy.

Motorcycle: Rudge 500 Ulster Manufacturer: Rudge Whitworth, Coventry
Type: Racing Year: 1928
Engine: Rudge single-cylinder, four-stroke, distribution through four parallel overhead valves, rod and rocker. Displacement 499.3 cc. (85 mm. x 88 mm.)
Cooling: Air
Transmission: Four-speed separate
Power: About 33 h.p.
Maximum speed: About 105 m.p.h.
Chassis: Single cradle, tubular, open below. Front, parallelogram suspension
Brakes: Front and rear, side drum, with automatic simultaneous operation

Rudge Whitworth  350 1930

1930 RUDGE WHITWORTH 350. In racing it is a very rare occurrence for a brand-new design, straight off the drawing-board, to go straight to the top; even rarer for it to dominate a T.T. Yet that is what Rudges did with their 350 c.c. model in 1930.
There had been racing 350 c.c. Rudges—or Rudge Whitworths to give them their correct name, as emblazoned on the tank—before this, but they had been a rather disappointing machine, apparently incapable of doing so well as their bigger brethren.

Then in 1930 came the new engine. Really it involved only a radical change in the actual cylinder-head design, for the new motor was almost identical in the bottom-half with the 500 c.c. one.
The old cylinder-head had employed four valves, the stems of each pair, inlet and exhaust, being parallel and operated by one rocker with two "fingers", one for each valve. This resulted in a poor combustion chamber shape, as the bore was too small to accommodate all the valves. Consequently, the head was of unnecessarily large diameter, leaving a lot of odd spaces.

All this was changed in the new head. Four valves were retained, but these were at the four "corners" of a perfectly hemispherical cylinder-head and stuck out radially—i.e., on a line that was a continuation of a radius of the hemisphere. To operate these a set of six rockers, three inlet and three exhaust, were carried on the head. They made a lot of clatter, but the power output was amazing.
In the cycle parts of the design, Rudges showed considerable advance on their contemporaries. Both wheels (they were q.d. and interchangeable) had 8-in. diameter brakes with wide shoes. Transmission was via a four-speed gearbox in which everything ran on needle roller bearings. A handlebar lever controlled the steering damper; both brakes were coupled to the pedal and compensated, with overriding hand control for the front.

The Rudge team consisted of Tyrell Smith, Ernie Nott and Graham Walker, and they cake-walked the race, Tyrell taking the record average speed up to 71-08 m.p.h.—the first time it had exceeded 70
Six famous racers. (Left to right) H. G. Tyrell Smith, Ernie Nott and Graham Walker, with the three Rudges with which they swept the board in the 1930 Junior T.T., finishing in that order. That was the last occasion on which a push-rod type of engine was to win a Junior T.T.

SPECIFICATION
Engine: single-cylinder 350 c.c. o.h.v.; four "fully
radial" valves. Ignition: magneto.
Transmission: chain via four-speed gearbox.
Frame: diamond pattern, with single down-tube to
front engine plate and single-seat pillar tube to
rear engine plates. Forks: single compression spring girders, with friction
damping.