BSA Rocket Gold Star (A10)

 

   

 

Make Model.

BSA Rocket Gold Star

Year

1962 - 63

Production

1584 units

Engine

OHV Parallel twin

Capacity

646 cc / 39.4 cub in.
Bore x Stroke 70 x 84 mm
Carburetor Amal Monobloc
Cooling System Air cooled
Compression Ratio 9.1:1
Lubrication Dry sump
Exhaust Single, stainless steel

Ignition 

Lucas magdyno

Battery

6V

Starting Kick start

Max Power

34 kW / 46 hp @ 6250 rpm

Optional RRT 2 close ratio gearbox: 37 kW / 50 hp

Clutch Multi-plate with built-in cush drive

Transmission 

4 Speed
Final Drive Chain
Frame Welded seamless steel tubing with duplex downtubes and full cradle engine support, bolted-on rear sub frame

Front Suspension

Telescopic forks with coil spring - hydraulically damped

Rear Suspension

Swinging arm, twin coil

Front Brakes

Drum, 8 in.

Rear Brakes

Drum, 7 in.
Wheels Shouldered alloy wheels, wire spokes

Front Tyre

3.25 x 19 in.

Rear Tyre

4.00 x 19 in.

Dimensions

Length:  2100 mm / 84.0 in.

Wheelbase 1391 mm / 54.75 in.
Dry Weight 143 kg / 315 lbs

Fuel Capacity 

16 L / 4.2 US gal

Top Speed 185 km/h / 115 mph
Colours Silver/chrome, Red/chrome
Source Wikipedia, Vintage Motorcycles Online, Bar Hopper Challenge, Classic Auctions
 
   

 

The BSA Rocket Gold Star (RGS) was the motorcycle that marked the final stage of development of the A10 twins.

"The engine for the RGS was the DA10 R engine only any other A10 engine prefix letter would not have been correct for a RGS. Same as for the frames used for Rocket Gold Stars; not the Gold Star single frame. The frames used were the regular A10 frames without the oil pump kink on the right hand bottom tube that is necessary on the Gold Stars. The significant thing about the RGS frame, the Gold Star frame and any other frame is the specific prefix letter/numbers. All swinging arm Gold Star frames start with the letter CB 32 and all of the very few RGS frames were GA 10; no other Swinging arm twin had this prefix which makes it easy to see if it is a genuine RGS.

The two years they were made were 1962 and 1963. The frames were GA10 101 onwards in 62 and GA10 390 onwards in 63." (Courtesy: Bill Carden)


Launched in February 1962, the total BSA Rocket Gold Star production was 1,584 bikes, of which 272 were off-road scramblers. The later (1961-1963) 9:1 compression Super Rocket engine was used with a BSA Spitfire camshaft and an Amal Monobloc carburettor gave 46 bhp (34 kW) as standard. Options such as Siamese exhausts and a close-ratio RRT2 gearbox could increase this to 50 bhp (37 kW) – and add 30% to the price. Nine specials were made for export to California and one was fitted with a sidecar by Watsonian for the Earls Court Show in October 1962.

The main reason for the demise of the popular Rocket Gold Star was the emergence of new unit construction successors, which meant that production ended in 1963.

 

Article by Nolan Woodbury

Val Page provided the A7 twin's roots, but it was Bert Hopwood's A10 rework that gave the Rocket its legs. Released in 1947 the post-war A7 did little to change public perception of BSA, but 1954 signaled an upturn with the A10-based Road Rocket and a top-five sweep at Daytona didn't hurt either. Using the double-downtube frame design popularized on the DBD-series GS models, the RR featured swinging arm suspension, an aluminum head and a racing Amal carb. Able to cruise at 80-mph, that first Rocket allowed BSA to take a share of the market back. Uprated in 1958 to Super Rocket tune, by 1962 the A65 was ready to take over flagship duties, but not before BSA crafted the ultimate A10; lavishing the RGS with a full checklist of performance upgrades.

Retaining the 646cc bore and stroke and magneto-mandated 360-crank, the engine specs of the Rocket Gold Star illustrate the highest level of performance tuning BSA applied to the production A10 twin. These include some features carried over from previous Rockets (aluminum cylinder head and a racing magneto with manual adjustment) and adding high compression 9:1 pistons, the 357 (Spitfire) cam and an optional siamesed exhaust system with Gold Star pattern silencers. In this form, the RGS produced nearly 50-hp; good for an honest 115-mph. Another 10-mph was possible with the proddy racing pieces like pistons with even higher domes, special valve springs and the Gold Star racing exhaust.

Just as critical in the RGS's appeal is the period IOM style and stance borrowed from the Gold Star single. These include a distinctive humped racing seat, shouldered alloy wheels and a fork-mounted speedo/rev-counter/headlight mount. Available at extra cost (fitted, seemingly, sooner or later) were low 'Ace' bars, gaitered forks, an alloy fuel tank and a close-ratio gearbox. The result was motorcycle with few styling peers, and one that backed its looks with real speed and handling.

Probably the most desirable BSA short of the legendary Goldie, copies of A10-based Rocket Gold Stars are growing in number, so check your facts and figures before buying. Expect to pay a premium for original examples, and more for machines that include the desirable options