Norton Classic
 | |
| Manufacturer | Norton Motorcycle Company |
|---|---|
| Also called | P43 |
| Production | 1987 |
| Engine | 588 cc air-cooled twin-rotor Wankel engine |
| Transmission | duplex primary chain, 5-ratio gearbox, single-row final drive chain |
| Wheelbase | 1,486 mm (58.5 in) |
| Related | Norton Interpol 2, Norton F1, Norton Commander |
The Classic is a rotary-engined motorcycle built in 1987 by Norton as a special edition of just 100 machines.
Engine development
The Classic used an air-cooled twin-rotor Wankel engine that had been developed by David Garside at BSA's Umberslade Hall research facility.[1][2] Garside, who had been impressed by the Fichtel & Sachs Hercules motorcycle, first installed a bought-in F&S air-cooled single-rotor engine into a BSA B25 'Starfire' frame as a "proof of concept". This proved reliable and smooth, but under-powered. Garside then created a prototype twin-rotor engine (with F&S rotors) which doubled the capacity of the earlier test "mule". This twin-rotor engine was installed in a BSA A65 frame.[3]
Wankel engines run very hot, so Garside gave this air-cooled motor additional cooling air that was filtered and drawn first through the interior of the rotors and then through a large pressed-steel plenum into the combustion chambers via carburettors.[4] The plenum (which doubled as the bike's semi-monocoque spine frame) enabled the transfer of much of the heat to the surrounding atmosphere. Also, the carburation process further reduced temperatures, but this fuel-air mixture was still hotter than ideal, and its volumetric efficiency remained somewhat impaired. The cooling air filter was mounted below the steering head (between the forks) to provide a partial ram air effect. The engine's main bearings and the inlet manifolds were fed by oil-injection lubrication, and the fuel-air mix also carried a mist of oil from the interior of the rotors, which helped to lubricate the rotor tips.[5]
The Norton Wankel engine was further developed at Staverton into the MidWest aero-engine. The Midwest engine's output increased from BSA's 85 bhp to nearly 110 bhp[6] by improving volumetric efficiency. This was achieved by dumping overboard (rather than burning) the hot rotor cooling air, and by feeding pressurised fresh cool air to the combustion chambers.
The Classic motorcycle
While its engine was revolutionary, in other respects, such as appearance, suspension and brakes, the Classic was a conventional standard motorcycle. The fork stanchions were protected by rubber gaiters; and a full enclosure protected the final-drive chain. The air-cooled Classic was lighter and more powerful than the only Wankel competitor in production, the over-complicated single-rotor Suzuki RE-5 motorcycle (which featured liquid-cooled jackets and an oil-cooled rotor).
The Classic was discontinued after a limited production run priced at £6,000 each,[7] and was succeeded by the liquid-cooled Norton Commander. Liquid cooling provided both greater reliability and greater power, at the expense of an arguably less attracive engine (which was concealed by a full fairing).
References
- ↑ The Wankel Rotary Engine: A History By John B. Hege page 137, ISBN 978-0-7864-2905-9
- ↑ Denniss, Tony (1990). "The Norton Rotary". Retrieved 14 August 2011.
- ↑ "Bike" magazine Summer 1973
- ↑ "Cycle World' magazine February 1971
- ↑ Bill Murray monograph 1985: "The decline of the British motorcycle industry"
- ↑ MidWest Engines Ltd AE1100R Rotary Engine Manual
- ↑ Salvadori, Clement. "Retrospective: Norton Classic, 588cc Rotary Engine: 1988" Rider Magazine, 22 November 2007. Retrieved: 2 August 2012.