Vincent HRD "GUNGA DIN" 1951

 

 

 

1951 VINCENT-H.R.D. "GUNGA DIN." Until he left the Vincent works in late 1951, George Brown raced a factory 1,000 c.c. n»in in scores of road races, sprints and hill climbs each year. The machine, whilst used as a mobile test bed for anything new being developed, was not radically different in any way from the production models built. It was virtually the prototype of the factory's "Black Lightning" racer.
George quickly became top of the class as far as handling big Vincents was concerned, and his racer was soon dubbed "Gunga Din", a name to be feared by the opposition for it usually meant "going to win"!

The big twin was essentially similar in conception to the Series A "Rapide", but was much "cleaner" externally, with no outside oil pipes apart from the feed and return to the tank. Instead of being housed in a frame, like the Series A, the post-war big twin-engine was part of the frame. A box girder also formed the oil tank and incorporated the steering-column tube at the front and the rear suspension anchor point at the rear.

A four-speed gearbox was built in unit with the motor, and so the pivot for the rear suspension could be fixed at the rear of the massive crankcase-cum-gearbox castings; a triangulated rear sub-frame worked on this pivot and was controlled by two compression springs and a hydraulic damper just under the seat nose.
Front suspension was taken care of by Vincent's own design of fork.

These used the traditional girder layout; the blades were of forged light alloy of oval section. Control was by two spring units compressed between the ends of the bottom rear fork spindle and points near the hub on the fork blades. A hydraulic damper was fitted between the top steering-column spindle and the bottom fork spindle—in the position usually occupied by a girder fork's spring. This gave a "girder" fork an amount of travel comparable with that of telescopies and the machine had a much stronger front end. Almost unbeatable in the 1,000 c.c. class at sprints and hill climbs.

The rider/machine combination were also frequent competitors at airfield circuits.

 SPECIFICATION
Engine: 500 Vee-twin r,ooo c.c. o.h.v.; valve operation
by high camshafts and short push-rods'. Ignition: magneto.
Transmission: primary drive via triple-row chain with slipper tensioner to four-speed gearbox in unit with engine; final drive by chain.
Frame: box-girder backbone, incorporating steering head and oil tank, bolted to cylinder heads; rear suspension by triangulated swinging fork with springs anchored to rear of box girder.
Forks: "Girdraulic" girders.

 

George Brown and his big twin-Vincent are seen here in action at Shelsley Walsh in September 1951.

Vincent HRD "RAPIDE" 1938

 

1938 VINCENT-H.R.D. "RAPIDE." The basic development of the pre-war Series A Vincent-H.R.D. "Rapide" . This engine was capable, with only modest tuning, of producing several more b.h.p. than the "works" 500 c.c. racers of the period, so it was only natural that soon after the introduction of the model some of them should appear on the race track.
Legend has it that one was raced (the name Ted Frend comes into the story) on grass tracks in the South-Eastern Centre. On wet tracks it proved an awe-inspiring spectacle . . . and soon after the "unlimited" races in grass-track programmes in the centre were listed as "up-to-650 c.c". It's rather a nice story!

The Vincent-H.R.D. factory had always produced "springers"; Vincent was a man who had invented a very good spring-frame at a time' when there were several very bad ones about, and he had joined forces with H.R.D. (Howard R. Davies, the 500 c.c. T.T. winner on a "350") to build the first Vincent-H.R.D.s in the late twenties.

It was no surprise, therefore, that when the "1,000" was announced it was equipped with pivoting-fork rear suspension. What was interesting was the employment of two brakes on each wheel, to provide stopping power to match the performance, and the latter was very good. After the various journals had tested the new Vincent-H.R.D., another maker of big twins stopped advertising his products as "the fastest production machine in the world".

The Achilles heel of the pre-war Vincent-H.R.D. was the transmission. Motor Cycling's road test spoke of clutch slip at over 100 m.p.h., and only if the clutch was kept in perfect condition could the full potential of the machine be realized.
"Ginger" Wood, seen in action in the picture, was one rider whose clutch worked. . . .

Specification

Engine: 47^° Vee-twin 1,000 c.c. o.h.v.; valve operation
by high camshaft and short push-rods. Ignition: magneto.
Transmission: chain through four-speed gearbox. Frame: single down-tube cradle type, with pivoting-fork
rear suspension. Forks: girder