Unit a series identification

A50	499cc OHV 2 cylinder 65.5mm x 74mm

December 1961	A50 Star Twin introduced. Unit construction engine, 4 speed, telescopic front forks and swinging arm rear suspension, 18” wheels, 7” brakes, 4 gallon tank, rectified lighting dual seat.

September 1963	A50A.101 Engine A50.5501 Frame A50 Star Twin magnetic speedometer, improved silencer.

September 1964	A50A.686 Engine A50.8437 Frame A50 Star Twin, folding kickstart, improved centre stand, needle race layshaft bearings.
	A50DC.101 Engine A50B.4001 Frame A50C Cyclone introduced, sports version of A50 Star Twin more powerful higher compression bench tested motor, different gear ratios, twin carburettors, 19” wheels, brakes 8” front 7” rear, rev counter as standard fitting, Siamese exhaust.
	A50DC.101 Engine A50B.4001 Frame A50CC Cyclone Clubman introduced, as A50 Cyclone but with dropped handlebars, rear mounted footrest and gear pedal, sports silencer, racing seat.

August 1965	A50A.1599 Engine A50.11889 Frame A50 Star Twin discontinued.
	A50D.551 Engine A50B.10761 Frame A50C Cyclone discontinued.
	A60DC.551 Engine A50B.10761 Frame A50CC Cyclone Clubman discontinued.

September 1965	A50R.101 Engine A50C.101 Frame A50 Royal Star introduced, as A50 Star Twin but with Lightning type frame, new front forks developed from Victor Grand Prix with two way damping, 6 plate clutch, 8” front brake, 12 volt rectified lighting, separate chromium plated headlamp, steering lock fitted, exhaust pipe tie, rear wheel speedometer drive, top access cap in chaincase.

August 1966	A50RA.101 Engine and Frame A50 Royal Star, finned rocker cover, primary chaincase panel for ignition timing, blade type rear mudguard.

October 1967	A50RB.101 Engine and Frame A50 Royal Star, Concentric carburettor, redesigned contact breaker.

October 1968	A50RC.101 Engine and Frame A50 Royal Star twin leading shoe 8” front brake, stop lamp actuated by either front of rear brake, modified pivoted rear fork, improved silencer.

November 1969	A50R.01656 Engine and Frame A50 Royal Star, stronger connecting rods, wider cylinder base flange to improve oil tightness, improved carburettor, new oil pump, front fork legs hard chromed with split ends and shuttle damping, points and rotor covers with BSA cast into them, smaller ignition coil.

October 1970	A50R.03939 Engine and Frame A50 Royal Star discontinued.

A65	654cc OHV 2 cylinder 75mm x 74mm

December 1961	A65.101 Engine A50.101 Frame A65 Star Twin introduced, generally as A50 but with bigger engine, 8” front brake.

September 1963	A65A.101 Engine A50.5501 Frame A65 Star Twin, magnetic speedometer, improved silencer, optional 12 volt electrics.
	A65B.101 Engine A50.5501 Frame A65R Rocket introduced, sports version of A65 Star twin with higher compression motor, Siamese exhaust, chromium plated sports mudguards.
	A65C.101 Engine A50.5501 Frame A65R Rocket as A65 Rocket but fitted with rev counter.

September 1964	A65A.1134 Engine A50.8437 Frame A65 Star Twin, folding kickstart, improved centre stand, needle race layshaft bearings.
	A65B.334 Engine A50.8437 Frame A65R Rocket, modifications as A65 Star Twin.
	A65C.1082 Engine A50.8437 Frame A65R Rocket with rev counter, modifications as A65 Star Twin.
	A65DC.101 Engine A50B.4001 Frame A65L Lightning introduced, as A65R Rocket but with more powerful bench tested motor, different gear ratios, twin carburretors, 19” wheels, rev counter standard fitting, Siamese exhaust.
	A65DC.2158 Engine A50B.4001 Frame A65LC Lightning Clubman introduced, As A65L lightning but with dropped handlebars, rear mounted footrests and gear pedal, sports silencer, racing seat.

August 1965	A65A.1673 Engine A50.11889 Frame A65 discontinued. Star Twin
	A65B.431 Engine A50.11889 Frame A65R Rocket discontinued.
	A65C.2586 Engine A50.11889 Frame A65R Rocket with rev counter discontinued.

September 1965	A65L.101 Engine and Frame A65L Lightning, new carburettors, twin exhausts, racing type dual seat, exhaust pipe tie, rear wheel speedometer drive three spring clutch, top access cap in chaincase, 12 volt electrics as standard, two way front fork damping.
	A65T.101 Engine A50C.101 Frame A65T Thunderbolt introduced, generally like A50 Royal Star but with bigger engine
	A65H.101 Engine A50C.101 Frame A65H Hornet introduced, scrambler type similar to A65 Lightning but with different gears, no silencers, upswept exhaust.
	A65S.101 Engine A50C.101 Frame A65S Spitfire MkII introduced, super sports roadster version of the A65H Hornet, with twin GP carburettors, 71/2 ” front brake.

October 1965	A65DC.7197 Engine A50B.10761 Frame A65 Lightning Clubman discontinued.

July 1966	A65HA.101 Engine and Frame A65H Hornet for export only.

August 1966	A65LA.101 Engine and Frame A65L Lightning, finned rocker covers, primary chaincase panel for ignition timing, blade type rear mudguard.
	A65TA.101 Engine and Frame A65T Thunderbolt, modifications as for A65L Lightning.
	A65SA.101 Engine and Frame A65S Spitfire now known as A65S Spitfire MkIII Special modifications as for A65L Lightning also Amal Concentric carburettors, chromium plated front fork upper shrouds.

November 1967	A65TB.101 Engine and Frame A65T Thunderbolt, concentric carburettor, redesigned contact breaker.
	A65SB.101 Engine and Frame A65S Spitfire know known as A65S Spitfire Mk IV, front brake 8” twin leading shoe, redesigned contact breaker.

December 1967	A65LB.101 Engine and Frame A65L Lightning, front brake 8” twin leading shoe, exposed chromium plated springs, twin concentric carburettors, redesigned contact breaker.

July 1968	A65SB.10618 Engine and Frame A65S Spitfire MkIV discontinued.

October 1968	A65TC.00101 Engine and Frame A65T Thunderbolt, balance pipe between exhaust pipes, improved silencers, twin leading shoe 8” front brake, stop lamp activated by front or rear brake, modified swinging arm, RM21 alternator, forks with split ends and shuttle damping, points and rotor covers with BSA cast into them, oil pressure switch.
	A65LC.00101 Engine and Frame A65L Lightning modifications as A65T Thunderbolt except twin leading shoe 8” brake already fitted, also twin windtone horns.

November 1969	A65T.00101 Engine and Frame A65T Thunderbolt, stronger connecting rods, bigger cylinder barrel base flange to improve oil tightness, improved carburettor, new oil pump, front fork legs hard chromed, smaller ignition coil.
	A65L.00101 Engine and Frame A65L Lightning, modifications as for A65T Thunderbolt, also new shape 31/4 gallon tank.
	A65FB.00101 Engine and Frame A65F Firebird Scrambler introduced. Roadster similar to A65L Lightning but with different gears, high level exhaust, 21/2 gallon tank, smaller headlamp.

November 1970	A65T Thunderbolt, new oil container frame, slimline front forks, competition type brakes, 21/2 gallon tank, modified air filter system, slightly upswept megaphone silencers, cast iron oil pump body.
	A65L Lightning modifications as A65T Thunderbolt.
	A65F Firebird Scrambler modifications as A65T Thunderbolt. Series letter changed to A65FS.

August 1971	A65F Firebird Scrambler discontinued.

December 1972	A65T Thunderbolt discontinued.

August 1973	A65L.EG.03508 Engine and Frame A65L Lightning discontinued.

A75 ROCKET THREE	741 cc OHV 3 cylinder 67mm x 70mm

April 1969	A75.00101 Engine and Frame A75 Rocket 3 introduced, 4 speed , telescopic front forks and swinging arm rear suspension, 4 gallon tank, brakes front twin leading shoe 8” , rear 7”, 12 volt rectified lighting, dual seat.

November 1969	A75.03417 Engine and Frame A75 Rocket 3, rear sprocket 53 teeth instead of 52 teeth, modified kick start ratio, new crankcase and gearbox gaskets fitted between gear box outer and inner crankcase faces to improve oil tightness, changed third gear ratio, larger horns.

November 1970	A75 Rocket 3 new slimline front forks, competition type brakes, new switch consoles, slimmer 21/2 gallon tank

October 1971	A75 Rocket 3 continued but with series letters changed to A75R.

December 1972	A75R Rocket 3 discontinued.