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Norton Commander – So Close to Revolutionary

blue Norton Commander still shot sideNorton Commander  It’s a question for the ages. What if, Norton had survived the death of the British motorcycle industry?

Though Norton ceased motorcycle production in the mid 1970s, they always intended the interlude would be temporary. The company had been working on developing a rotary-engine motorcycle. 

BSA Group purchased a Wankel licence from NSU in the 1950s, but never capitalized on its investment, though they did produce a prototype engine based on a Fichtel and Sachs design. The intellectual property rights passed to Norton-Villiers when that company acquired the remains of BSA around 1972. The rotary engine project was tasked to one of the British motorcycle industry’s most talented development engineers: Doug Hele. 

As early as 1979, Norton registered a prototype fitted with an air-cooled, twin-rotor engine of nominal 583cc capacity. The engine was mated to a five-speed transmission based on a Triumph Trident unit and mounted in a new frame with Marzocchi forks, Radaelli wheels, Brembo triple disc brakes, and Girling shocks. In spite of an enthusiastic reception by the sporting press, the Aurora never went into production. Instead, Norton decided to focus on the P41, a police-spec bike introduced in 1984 using the air-cooled engine and sold as the Interpol 2. 

The Norton Commander was the product of an ambitious business plan drawn up by Philippe LeRoux, head of Norton Group, a public company formed in 1987. The plan included repackaging the air-cooled Interpol 2 as a naked street bike (the P43 Classic); a sophisticated sport touring motorcycle with a liquid-cooled engine positioned for the luxury touring and police sectors (the P52 Interpol and P53 Commander); and a production racer aimed squarely at the 1988 Honda VFR750R (the P55 F1).

Liquid cooling was adopted mainly to reduce mechanical noise, but it also allowed a compression boost for more power. The 85-hp engine was still matched to a Triumph-based five-speed transmission via a duplex chain and diaphragm-spring clutch with chain final drive in a fully enclosed chain case. The drivetrain was hung from a box-section spine frame, which also contained the intake plenum chamber and a two-quart oil tank. 

blue Norton Commander still shot rear quarterThe Commander used a Kayaba telescopic front fork and swingarm rear suspension with Koni spring/shock units. Much of the rest of the equipment, including the wheels, brakes, instruments and controls were borrowed from Yamaha’s XJ900 Diversion. Bodywork was essentially that of the Interpol 2 with fixed panniers. These were intentionally designed to be no wider than the fairing. (Later production Commanders had removable Krauser bags.)

The intake system of the Commander engine needs a little explanation. Intake air is drawn through the rotor core to draw heat away. The intake charge then passes to the plenum chamber to cool before being feeding two SU constant-vacuum carburetors. 

In the Norton Commander, the carburetor butterflies are positioned close to the rotor intakes, while the SU’s fuel-mixing CV piston “dashpots” are located further back in the intake, just after the plenum. This allows fuel vaporization to further cool the intake charge. A separate idle circuit with remote idle speed adjuster carries fuel/air mixture direct to the rotor intakes, bypassing the butterflies.

Lubrication is by a throttle controlled pressure feed to the main bearings and rotor synchronizing gears. The intake air inevitably picks up oil vapor on its way through the rotor, much of which then condenses inside the frame plenum chamber. A vacuum takeoff from the left intake manifold draws excess oil out of the plenum where it’s burned in the left side combustion chamber. Many owners install a catch bottle in the vacuum line to avoid over-oiling the left rotor.

The Norton Commander went on sale in 1988 and received a broadly positive response from testers: “…none of us had any doubts that the Commander was a bit special and rather good in its intended role of sports/tourer,” said one magazine in 1988. “Numbers can’t convey its smoothness or seemingly frictionless turbine power.” 

Criticism was mostly limited to the fact that accessing the reserve fuel tap required removing the bodywork; and that the panniers were not removable. Unfortunately, at GBP 7,500, the Commander was also 20 per cent more expensive than the benchmark luxury sport tourer, BMW’s K100RT; and 50 per cent more than the better-equipped Kawasaki 1000GTR. Nor did Norton have a dealer network: all service work had to be done at the Shenstone factory. In the end, fewer than 300 Commanders were built. And by 1992, Norton was badly in debt and under management by its biggest creditor, Midland Bank. Motorcycle production ceased. 

The Commander looks bulky and unwieldy but feels light and easy to handle from the seat. The engine fires immediately on the starter and settles to a burbling idle. The clutch is light, and I have no problem selecting first. Pulling away is a breeze, and I’m reminded of an FJR1300, so smooth and tractable is the engine. 

blue Norton Commander still shot frontShifting is light, acceleration is brisk, and the engine surprisingly smooth and quiet—just a rustle from the motor and a two-stroke-like drone from the exhaust. And like a two-stroke, the motor offers almost no engine braking. Handling is neutral, the bike feeling light and nimble in the turns, and easy to maneuver at low speeds. It’s deceptively peaceful behind the large windshield, and I can imagine covering hundreds of cross-country miles in dignified comfort. 

With the passing of the Mazda RX-8 in 2011, rotary-engine road vehicles have become extinct, unable to meet ever more stringent emission requirements. But the Norton rotary engine lives on, still manufactured for use in drone aircraft where its light weight and compact size are prized. Like so many in the British motorcycle industry, the Norton Commander story remains a “what if?”

By Robert Smith Canadian Biker Issue #317


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