Matchless G9 Twin

   

Make Model

Matchless G9

Year

1948 - 58

Engine

Parallel twin cylinder

Capacity

498 cc / 30.4 cub in.

Bore x Stroke

66 x 72.8 mm

Cooling System

Air cooled

Compression Ratio

7.7:1

Lubrication

Dry sump

Engine Oil

Hot: SAE 50

Cold: SAE 30

Extremely Cold: SAE 20

Oil Capacity

2.5 L / 5.3 US pints

Exhaust

Twin, chrome, megaphone silencers

Fuel System

Amal 376/6

Ignition 

Magneto, Lucas K2F

Starting

Kick

Battery

Lucas, 6V 12 Ah

Spark Plug

KLG FE80, 14mm thread

Maximum Power

24.3 kW / 33 hp @ 6800 rpm

Transmission 

4-Speed

Final Drive

Chain

Gear Ratios

1st 2.67 / 2nd 1.77 / 3rd 1.35 / 4th 1.0:1

Frame

Single top and down pipe, double cradle

Wheelbase

1403 mm / 55.25 in.

Front Suspension

Teledraulic

Rear Suspension

Swingarm, twin shocks and coil springs, oil dampers

Front Brakes

Drum

Rear Brakes

Drum

Wheels

Steel, wire spokes

Front Tyre

3.25 x 19 in.

Rear Tyre

3.50 x 19 in.

Dry Weight

181 kg / 400 lbs

Fuel Capacity 

17 L / 4.5 US gal

Top Speed

137 km/h / 85 mph

Colours

Black, Red

Source Wikipedia
   

The Matchless G9 and corresponding AJS Model 20 were launched at the post war Earls Court motorcycle show in late 1948. Initially for export to the US, it was not until the late summer of 1949 that the first examples reached the home market. The styling was modern and the dual seat, megaphone silencers and bright chrome finish justified the name of Super Clubman for the matchless and Spring Twin for the AJS. The rest of the cycle parts were standard AMC, with the engine being housed in a pivoted fork frame with telescopic front forks. The basic design changed little over the course of the next few years, the most significant change being made in 1952 when a new Burman gearbox was adopted.
In 1951, the rear suspension was upgraded to the Jampot unit, derided for its shape in the 28 September issue of the Motor Cycle magazine. In the same year minor changes included a new Lucas horn-push on the handlebar and a medallion badge in place of the previously used transfer. Front fork shuttle damping was also replaced with rod and damper-type.
Progressively developed, the G9's twin-cylinder engine underwent a number of capacity increases, finally being discontinued when the 646cc Matchless G12 (and AJS Model 31 replaced it in the autumn of 1958.