1920 BSA 770cc Engine & Gearbox Diagrams
(L.) The new B.S.A. gear box, embodying s redesigned multi-plate clutch. Engagement of gears is by dog clutches.
(R.) Of a particularly clean design, the new B.S.A. 6 h.p. twin engine has many features revealing road experience.
Article: BSA 1920 770cc 6hp TwinCredit: The Motor Cycle