1915 750cc AJS V-Twin Model D
With an original capacity of 698cc, the model
D first appeared at the 1912 Motor Cycle Show,
thus beginning the long line of AJS big twins
which ended with the 1000cc machine of the late
It was quite an advamced machine for its time,
being equipped with all-chain drive and a three
speed countershaft gearbox. The first engines
had detachable cylinder heads but following
customer complaints of joint leakage, integral
heads were introduced on the 1913 machines.
By 1915 the capacity had been increased to 748cc
and externally the appearance was altered by
the use of a dropped top tube frame and the
raher attractive tapered fuel tank.
In 1916, detachable cylinder heads were again
in use but in the early part of the year motor
cycle production ceased. The firm having missed
out on motor cycle contracts for the Services
the factory had to change over to munitions
and the big twin went into cold storage for
the duration, reappearing at the 1919 show.
Engine - 74 x 87mm = 748cc side valve V-Twin.
Total loss lubrication by hand pump. Splitdorf
Magneto ignition. Amac automatic carburettor.
Cast aluminium silencer.
Transmission - All chain drive via AJS three-speed
Cycle Parts - Open diamond type tubular frame.
Brampton bi-flex front forks. Quickly detachable
rear wheel. Stirrup front brake, foot operated
drum type rear brake. Very wide valance to front
Tyres - 650 x 65
Weight - 276 lbs