For the man who wants a lightweight model that combines economy, easy handling, simplicity of maintenance and a satisfying performance, the answer is the B.S.A. 250 side valve model. It is attractively finished in two tones of green enamel.
C10 1938-57
249cc, sidevalve single, 310lb, 75mpg, 55mph
Introduced shortly before the war it had a rigid frame, girder forks, minimal brakes and side-valve engine. Primitive telescopic forks were introduced in 1949.
ENGINE. Single cylinder S.V., 63 mm. bore x 80 mm. stroke, 249 c.c.; dry sump lubrication; enclosed valve gear; ball bearing on mainshaft, drive side; roller bearing big-end: detachable cylinder head; Amal carburettor; coil ignition with car type distributor and automatic advance; improved exhaust system.
TRANSMISSION. Engine-shaft cush drive; front chain ½in. x .305 in. running in flush-fitting oil bath; rear chain ½in. x .305 in. with guard; improved B.S.A. 3-speed gearbox with built-in positive-stop foot gear-change; gear ratios 6.6, 9.8, 14.5.
FRAME. Triangulated type; front fork shock absorber with finger adjustment; 2 ½ gallons petrol tank: 4 pints oil tank under saddle; brakes 5½ in. dia. with finger adjustment; improved forged steel central stand; lifting handle on rear guard: integral lugs on chainstay for pillion footrests. Folding pillion footrests extra.
CONTROLS. Adjustable handlebar with twist-grip throttle and B.S.A. grouped controls incorporating clutch lever, carburettor air lever and headlamp dipper switch on left, front brake lever and horn button on right.
EQUIPMENT. Dunlop 3.00 x 19 tyres; Lucas 6-volt dynamo lighting set with compennsated voltage control; electric horn: spring seat saddle; rubber kneegrips on petrol tank; metal toolbox with complete tool kit; tyre inflator; licence holder. Speedometer extra.
FINISH. Matt silver and chromium petrol tank; black oil tank; chromium brake-cover plates; polished timing, tappet and gearbox covers; matt silver wheels with black lines: black frame.
DIMENSIONS. Wheelbase 52 ins.; saddle height 28 ins; clearance 51 ins; overall length 80 ins; overall width 29 ins.
