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1966 Matchless G80

The G80 was Matchless‘s top-of-the-line 500 single. Launched in 1949, just as civilian production was ramping back up after World War 2, it was soon competing against an entire field of new vertical twins from Triumph, BSA, Norton, and the rest. On the dirt, the mighty G80 faired quite well, and on the street the big single held its own against other big singles, which ruled the roads up until this time. However, times were changing and progress was on the march. As street bikes, the big singles couldn’t hold a candle to a good vertical twin, in terms of power, and most importantly, vibration, or the lack of it. The 1966 Matchless G80 was the product of decades of development, enjoyed great success during it’s lifespan (1949-1966) commercially and on the racetrack. But the end was drawing near. Matchless, and its sister-brand AJS, were both owned by AMC (Associated Motor Cycles, not to be confused with American Motors), along with Norton and some others. AMC struggled throughout the 1960s, paring off models and entire brands to try to find that profitable ‘sweet spot’. By the early 60s, the only bikes AMC was producing were the Matchless and AJS singles (pretty much the same bike), and big Norton twins. Even this wasn’t enough, and they slid into insolvency in 1967. The only brand that survived was Norton, and almost entirely because of the so-new-it-hadn’t-come-out-yet Commando, which arrived in 1968. Alas, the market for big British singles had pretty much dried up, thanks in large part to the “Japanese Invastion“. The 1966 Matchless G80 was the last big single that Matchless built, probably one of the last motorcycles of any kind. The G80 represented the archetypical British design and was perhaps the ultimate manifestation of it. Big air-cooled single with a small bore and very long stroke, cam gear and pushrods on the right driving rocker arms up to, primary chain driven off the left side, feeding a non-unit-construction gearbox out back. It was a classic design repeated many times by many British manufacturers, and it served them very well from about four decades.

1966 Matchless G80 SPECIFICATIONS

1966 G80 Models:

Engine type:


Bore & Stroke:

Compression ratio:

Fuel system:

Ignition system:

Lubrication system:

Engine output:

Primary drive:



Final drive:


Suspension, front:

Suspension, rear:

Brake, front:

Brake, rear:

Dry weight:

Top speed:

1966 Matchless G80, G80C, G80CS, G80S

Air-cooled OHV vertical single

498cc / 30.2 ci

82.5mm X 93mm


1X Amal Monobloc 27mm carburetor

Lucas magneto

Dry sump

28 hp @ 5600 rpm


Multi-plate, wet

4-speed constant mesh, right-foot shift


55.0″ / 1397mm

Teledraulic forks

Swing arm w/2 Girling dampers (shocks)

SLS drum

SLS drum

390 lbs / 177 kg

78 mph / 126 kmh

Check out these MATCHLESS BOOKS

Matchless: The Complete Story

Matchless, once the largest British motorcycle manufacturer

AJS and Matchless Post-War Singles and Twins: The Complete Story

Motorcycle Apprentice: Matchless – in name & reputation (Classic Reprint)

History of Matchless Motorcycles

Matchless and Ajs Restoration

BOOK OF THE MATCHLESS 350 & 500cc SINGLES 1955-1966

AJS and Matchless: The Post-war Models

AJS and Matchless Gold Portfolio 1945-1966

Illustrated Ajs and Matchless Buyer’s Guide (Illustrated Buyer’s Guide)


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