1968 650cc BSA A65 Spitfire MKIV

The 1968 MkIV version of BSA's speedy 650cc Spitfire twin was the last of the line. Two particular features distinguish it from its immediate predecessors, the first unit-construction A65 Spitfire MkII of 1966 and the MkIII of 1967.

Firstly, the MkII's Amal GP racing carburettors were replaced by the same maker's newly-introduced Concentric instruments on the 1967 MkIII. Secondly, the 1968 version has the twin-leading-shoe front brake introduced on BSA and Triumph 650s for that year, providing greater stopping power than the previous drum.

Less obvious technical changes for 1968 included the latest independently adjustable Lucas ignition points, providing accurate spark timing for smoother running, along with lubrication system improvements. During 1967, engine power output was boosted to more than 53 horsepower and BSA promoted its top performer in Production class racing. A factory-prepared Spitfire finished third in the 1968 750cc Production TT, behind two 750cc machines and was timed at over 132mph on a section of the Mountain course.

This MkIV is in European trim with a large moulded fuel tank: US export models usually had a smaller tank and high-rise handlebars. Side-facing reflectors, under the front of the tank and on the rear lamp unit, were mandatory on American road machines from 1968.

The A65 Spitfire was replaced as BSA;s top roadrunner with the launch of the 125mph three-cylinder 750cc A75 Roocket III late in 1968.