Zenith 1911 500cc 1 cyl sv 2706
Zenith 1911 “Gradua” 3 ½ HP 488 cc JAP single frame # 1127 engine # 2736
Zenith’s chief Engineer Freddy Barnes was responsible for the famous “Gradua” gear.
The mechanics of the Gradua gear were a variable engine pulley worked by a handle, with simultaneous correction of the belt length made by sliding the rear wheel backwards or forwards in the fork slots.
Its advantage showed itself most effectively in speed hill climbs.
The Zenith rider could change during the journey up while the other competitors had to make do with a single choice of gear ratio.
Rival riders and manufacturers thought that this was an unfair advantage so many leading clubs barred Gradua gear Zeniths from their hill climbs.
Zenith was quick to recognize the publicity value and took the word “barred” as their trademark.
The 1911 range consisted of a 3 ½ HP single and a 6 HP twin, both powered by an engine of Prestwich design.
Among the improvements for 1911 were a more powerful parallel motion foot brake on the belt rim with very large leverage and a neat form of tool bag with case for spare inner tube.
Note the very practical centre stand!
This technically highly interesting machine is fitted with Lucas bulb horn and generator, Miller lights, Bosch magneto and Brown & Barlow carburettor.
This Gradua is spic and span and comes complete with Pioneer Certificate.