BSA Rocket 3 (A75)
The bike was originally to be called the BSA A75 Tri Star but this was subsequently changed to Rocket 3. The Rocket 3 is in most respects the same as the Triumph Trident T150. It differs in having cylinders inclined at fifteen degrees from the vertical and the use of a twin down tube frame. As with the Triumph variant, Ogle styling was adopted.
Engine
OHV air cooled transverse 3 cylinder
Bore and stroke 67 x 70mm
Capacity 741cc
Compression ratio 9.5:1
Claimed output 58bhp @ 7250rpm
Carburation 3 x Amal 27mm concentric
Raygun silencers
Transmission
Endless triplex chain primary drive
Borg & Beck single plate dry clutch
Four speed constant mesh gearbox
Frame
Duplex cradle, all welded tubular
Suspension
Triumph type telescopic front forks
Girling rear shock absorber struts
Wheels and Tyres
Front rim WM2 x 19”
Rear rim WM3 x 19”
Front tyre 3.25 x 19” Dunlop K70
Rear tyre 4.10 x 19” Dunlop K81
Brakes
Front 8” dia. Twin leading shoe drum
Rear 7” single leading shoe drum
Tank capacities
Fuel 4.25 gallons
Oil 5 pints
Electrical
12V 8Ah battery
Lucas 120W alternator
Lucas rectifier and zener diode regulator
Dry weight
470lb
Colour Schemes
Black frame, Flamboyant Red or Flamboyant Blue
1970 changes
4.10 x 19” Dunlop TT100 front tyre
Revised gearbox ratio – 3rd gear lowered slightly
1971 changes
Optional 5-speed gearbox
Conical hub front and rear brakes
No front fork gaiters, Girling exposed spring rear units
Direction indicators
Colour scheme, Flamboyant Red/Flamboyant Blue/Firecracker Red. Frame Dove Grey
1972 changes
5-speed gearbox is fitted to some BSA A75
Colour scheme, black frame, Burgundy