AJS R7 1938
1938 A.J.S. R7. From the late twenties until the
1961 season, at least, the A.J.S. 350 c.c. racer has been a powerful force in
the Junior class. It has undergone many changes, from a rigid-framed, spindly
looking device capable of some 80 m.p.h. to an all-sprung compact design capable
of approaching 120 m.p.h., but one design feature has remained constant
throughout the period—the drive to the overhead camshaft has been by a chain.
(An experimental engine in the mid-fifties had a shaft and bevels but was never
By 1938 the motor had light-alloy head and barrel
with hairpin valve-springs and the magneto was behind the barrel instead of in
front of the crankcase as on the early models. The rear pivoting-fork springing
was unusual in that each "side" of the fork was a two-piece girder, rather like
the bottom part of a girder fork, and this must have given far greater rigidity
than a single-tube type.
Forged light-alloy back plates were used for both
single-leading-shoe type brakes, and the front unit had a huge, near-full-width
alloy hub and very long torque arm. In the 1938 T.T. a light-alloy rim was
fitted to the front wheel on the "works" models, but the same machines used in
the 1939 Island races had reverted to steel rims.
Whilst technically very interesting, the pre-war
350 c.c. A.J.S. did not cover itself in the glory achieved by its post-war
descendants. This could well have been because the factory development staff was
concentrating on the 500 c.c. four-cylinder models. Whatever the cause, the best
Junior T.T. place gained in the thirties by the model was eighth in both 1935
Engine: single-cylinder 350 c.c. o.h.c; light-alloy head
and barrel, chain drive to camshaft. Ignition: Lucas magneto.
Transmission: chain via four-speed Burman gearbox. Frame: cradle type with
single down-tube and swinging-■ fork rear suspension, controlled by
"plunger-type" spring boxes.
Forks: girder pattern with single compression spring and twin rebound springs.