Star Twin SPECIFICATIONS, PRICE & IMAGES

Bike Features

Make Model:

BSA Star Twin / Royal Star

Year:
1962 – 72

Engine:
Four stroke, parallel twin cylinder, OHV, 2 valves per cylinder

Capacity:
654 cc / 39.9 cub in.

Bore x Stroke:
75 x 74 mm

Carburetor:
Amal monobloc 389/67

Cooling System:
Air cooled

Compression Ratio:
8.0:1

Lubrication:
Dry sump

Engine Oil:
SAE 20W/50

Oil Capacity:
3 L / 5 pints / 0.79 US gal

Exhaust:
Twin, stainless steel

Ignition :
Twin coil

Spark Plug:
Champion N4, 0.5 mm / 0.02 in gap, 14 mm dia thread, 19
mm reach

Battery:
Prior 1966:
6V, 13 AH, Lucas RM19 alternator
Post 1966:
12V, 9 AH, Lucas RM19 Alternator

Starting:
Kick start

Max Power:
40 kW / 54 hp @ 4500 rpm

Clutch:
Multi-plate with bult-in cush drive

Transmission  :
4 Speed

Final Drive:
Chain

Gear Ratio:
1st 11.49 / 2nd 7.32 / 3rd 5.24 / 4th 4.58:1

Frame:
Steel tubing, cradle

Front Suspension:
Telescopic forks with coil spring – hydraulically damped

Rear Suspension:
Coil spring/hydraulically damped

Front Brakes:
20.32 cm / 8 in., drum

Rear Brakes:
17.78 cm / 7In., drum

Wheels:
Steel, wire spokes

Front Rim :
WM2-18

Rear Rim :
WM2-18

Front Tyre:
3.25 x 18 in., ribbed

Rear Tyre:
3.50 x 18 in., K70

Dimensions:
Length: 
2060 mm / 81.0 in.
Width:    
711 mm / 28.0 in.
Height:  
1010 mm / 39.8 in.

Wheelbase :
1372 mm / 54.0 in.

Ground Clearance :
178 mm / 7.0 in.

Seat Height:
813 mm / 32 in.

Wet Weight:
176 kg / 390 lbs

Fuel Capacity :
Europe:18 L /
4.8 US gal
US: 9 L / 2.4 US
gal

Average Consumption :
4.7 L/100 km / 21.3 km/l / 50 mpg

Top Speed:
160 km/h / 100 mph