AJS G2 Servise Manual page 4

Technical details, together with working instructions given in ensuing
chapters are solely confined to the single cylinder A.J.S. and Matchless
models, which are similar regarding design, and identified by the petrol
tank emblems and colour finish. The engine design of the heavyweight
single cylinder models is basically identical since 1948, and in consequence
the engine assembly instructions—in the main—apply to all models made
from 1948 to 1966. The lightweight models were introduced in 1959 and
design changes with minor modifications are described to enable owners
to incorporate the later parts into earlier engines, if so desired.
As the crankcases for the 350 and 500 heavyweight engines are identical
—since 1948—the small capacity engine can be converted to the larger
type by substituting parts in the top portion of the engine.
The author and the publishers wish to express their thanks to Norton
Villiers Ltd. for their co-operation in the preparation of this book and
permission to publish the text and illustrations.