Matchless G3


Make Model

Matchless G3




Single cylinder, four stroke, OHV


348 cc / 21.2 cub in.
Bore x Stroke 74 x 81 mm
Cooling System Air cooled
Compression Ratio 8.5:1
Lubrication Dry sump
Oil Capacity 2.8 L / 5.9 US pints
Exhaust Single, chrome silencer

Fuel System

Amal Monobloc carburetor, 1-1/8 in


Coil, Lucas alternator
Battery 6V
Starting Kick
Clutch Wet, multi-plate


Final Drive Chain

Maximum Power

16.9 kW / 23 hp @ 6200 rpm


Tubular cradle, twin downtubes

Front Suspension

Telescopic fork with hydraulic damping
Rear Suspension Pivoted rear fork controlled by Girling 3-position spring-and-hydraulic units

Front Brakes

178 mm / 7 in. drum, finger adjustment

Rear Brakes

178 mm / 7 in. drum, finger adjustment
Wheels Steel, laced wire spokes

Front Tyre

3.25 x 19 in.

Rear Tyre

3.50 x 19 in.
Wheelbase 1436 mm / 56.5 in.
Ground Clearance 165 mm / 6.5 in.
Seat Height 775 mm / 30.5 in.

Wet Weight

179 kg / 395 lbs

Fuel Capacity 

19.3 L / 5.1 US gal

Average Consumption 

3.3 L/100 km / 30 km/l / 71 US mpg

Top Speed 129 km/h / 80 mph
Colours Black, Red
Review Classic Bike, May 1991

The 348cc G3 launched for 1962 represented a major shake-up of the roadster single. Its engine dimensions are 74 x 81mm like the earliest version of the OHC 7R racer. The cast-iron crankshaft flywheels used since G3L days were kept, however. Outwardly, the engine changed in having its pushrods enclosed in tunnels cast into the iron barrel. The short-stroke 350s were sold in G3S and G80S sports versions, though alterations from touring specification seem to have been purely cosmetic. Buyers seeking the plonk of a traditional long-stroke engine will prefer the earlier units, but the rare interim 350 offers snappier acceleration.

Large cast-alloy 'knee-knocker' tank badges used from 1962 are frowned on by purists, but they have a nice period style. Wider shoes improved the front brake from 1963, although all alloy-backplate front drums need to be checked for cracks. Norton front forks and wheel hubs mark out machines from '64 on. And while they may not appeal tomarque die-hards, handling is fine, and Norton's 8in front drum is a useful brake. Shorter riders may welcome the change from 19in to 18in for both wheel rims thatyear.

Roadster engine design benefited from amalgamation with scrambler dimensions for 1964. The CS's 85.5mm stroke, a feature of motocross engines since 1956, became common across the whole heavyweight single range, which also acquired steel flywheels and a roller bearing on the crank's timing-side main-shaft. A beefier big-end. All engines from '64 have integral pushrod tunnels in their cylinder barrels, although the latter are of iron, and not alloy as used on competition machines from 1950.

A limited quantity of export-style road-legal G80CS models was sold on the British market in 1967. This is a highly desirable street scrambler, so you can expect to pay over £3000 if you find one. Re-imported G80CS models from the US are also quite popular and should come a little cheaper.