Vincent HRD "GUNGA DIN" 1951

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

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.