124 pages, 78 black & white illustrations, size 5.5 x 8.5 inches. Originally published under the title The Second Book of the BSA Twins by A.G. Lupton, this boo

The BSA 500 and 650cc Unit Twins were the top-of-the-range models for BSA from the early 1960s through to the Rocket 3 of 1969. The model range covered every an