Norton 650SS – A Lasting Influence

I know personal perspective is an important factor in aesthetics: but to my eye, motorcycle design peaked in the late 1960s. It hasn’t been all downhill since then—Laverda Jota, BMW G/S, Ducati 916, MV Brutale—but the fundamentals were set by 1970. Who remembers king and queen seats, Windjammer fairings and ducktail fenders with visual affection? Not me, for sure. Neither am I surprised that so many plastic-clad sportbikes became streetfighters. And some of the most revered modern naked bikes are just today’s take on the same plot: lots of engine presence, bodacious exhaust, minimalist instrumentation; and black, black, black. 

Take the 1962 Norton 650SS, for instance: a bad boy in black (natch), silver and chrome; paired speedo and tachometer, flat bars (a Norton trademark), humped dualseat, swept back exhaust … To sixties sensibilities, it spelled speed and sex the same way a Gixxer does today.

Oddly, though BSA and Triumph had been selling a 650 since 1949, Norton resisted getting into bigger cubes. Three factors may have contributed to that. First, Norton had been sold to AMC, the Matchless and AJS parent, in 1953, and there was overt hostility between the new London-based owner and its Bracebridge Street, Birmingham subsidiary. AMC had its own Twins, the AJS Model 20 and Matchless G9, and development of these seems to have taken priority. 

Norton also based much of its advertising on the prowess of its racing Manx. Race shop boss Joe Craig was fiercely defensive of his budget and until Norton quit racing in 1957, development funds were directed to the Manx program. 

Thirdly, what sporting Norton buyers wanted was the race-derived Featherbed frame. Norton lacked the facilities to build the all-welded chassis, so contracted the work to frame maker Reynolds. While Reynolds got up to speed, Norton continued to put most of its Twins into old-fashioned lug-and-braze frames: only the sporting Dominator models 88 (500cc) and 99 (600cc) got the Featherbed frames. Had Norton built a 650 in the mid-fifites, it’s doubtful Featherbed frame production could have met demand.

Norton did get a Featherbed 650 in1961—the Manxman tourer—but it was only available for export. Finally, in 1962 the 650SS arrived and was an instant hit. It seemed to be the bike every Norton Twin should have been. But it was top dog for scant seconds. In the same year, AMC-Norton introduced the 745cc Atlas, a big bore version of the 650, again intended for the US market. As a result, few Norton 650s made it across the pond.

The 650SS was essentially a stroked version of the model 99SS, with dimensions of 68 by 89mm (the 99’s stroke had been 82mm). Like the top Dominator, the 650SS breathed through twin Amal Monoblocs, but with the intakes now angled downwards. Twin exhausts replaced the 99SS “siamesed” system, and the headlight nacelle was dropped in favor of matched speedometer and tachometer. Finish went from the 99SS two-tone scheme to a classic black frame, silver painted tank and (optional) chrome fenders. Though simple in concept, the overall effect was stunning. The black, silver, polished alloy and chrome finish created “the look” for sports motorcycles for a decade—until the metalflake seventies.

Sadly, the Atlas always overshadowed the 650SS. After all cubes are cubes, and the Atlas simply had more. The 650SS was last produced in 1967, though a single carburetor version, the Mercury, continued until 1969.

HOPWOOD’S “BETTER” TWIN

Working under Edward Turner at Triumph, Bert Hopwood had first hand knowledge of both the good and bad features of the 500cc Speed Twin engine. So it’s no surprise that the 500cc twin he designed for Norton in 1947 included many improvements over Turner’s engine. 

In Hopwood’s design, a single camshaft mounted in the front of the engine operated all four pushrods, and was driven by chain from a half-speed idler gear to minimize valve train noise. Exhaust ports were splayed widely for better cooling, and an improved combustion chamber design allowed higher compression ratios. Announced for the 1949 season, the 500cc Norton twin was a latecomer: Triumph’s Speed Twin had been launched in 1937, BSA’s first 500 twin in 1946, and Ariel’s in 1948. 

That said, Hopwood’s basic design for Norton was so good, it was still in production almost 30 years later as the 850 Commando. In this time, the dimensions had gone from the 66 by 72.6mm of the 500 to 77 by 89mm, and power output had more than doubled. Not surprisingly, as engine dimensions and state of tune increased, so did vibration. The 745cc Atlas engine at 73 by 89mm was really only acceptably smooth when rubber mounted in the Commando frame. Many said that the 650SS gave the best compromise of performance and smoothness.

DEREK STEELE’S 650SS

I first saw Steele’s delightful 650SS at a meeting of the Westcoast Brtish Motorcycle Owners’ Club in Vancouver, BC. At first I thought it was an early Atlas—telling them apart isn’t that easy, and given that the 650SS is such a rare commodity in North America. Steele’s bike is from 1962, the first year of the SS model, and is essentially stock except for a few sensible upgrades. Concentric carburetors replace the original Monoblocs, which were prone to flooding during cold starting because of the 650SS’s steep downdraft intake angle. In any case, Concentrics were fitted in the model’s last year, 1967.

Steele has also replaced the magneto with a Boyer electronic ignition setup, the pickup housed in a neat casing behind the cylinders where the mag. used to be. Electrics were upgraded to 12 volt at the same time. And a ventilated twin leading shoe drum front brake produced by sixties sidecar racer and Norton tuner John Tickle replaces the Norton single leading shoe version. The only other deviation from standard is a pair of period Dunstall mufflers replacing the cigar-shaped stock units.

What’s it like to ride? “It feels very nimble, yet stable at the same time,” says Steele. “And it has that organic, visceral feel you get from a British bike—as though you’re connected to the machine.” 

Robert Smith, Canadian Biker Issue #237

MORE VINTAGE CONTENT