1968 650cc BSA A65 Spitfire
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.
Engine - 654cc (75 x 74mm) air-cooled overhead
valve parallel twin, 10:1 compression ratio,
two Amal carbnurettors, coil ignition
Transmission - Triplex chain primary drive,
wet multi-plate clutch, four-speed gearbox
and chain final drive
Chassis - Tubular double cradle frame, telescopic
fork front suspension, swinging arm rear suspension,
drum brakes. Wheels 19in front, 18in rear
Power - 54bhp @ 7250rpm
Dry weight - 408lb (185kg)
Top speed - 15mph