Norton Mercury Explained

Norton Mercury
Manufacturer:Norton-Villiers
Production:1968-1970
Assembly:Plumstead, London
Predecessor:Norton 650SS
Engine:646cc air-cooled OHV vertical twin
Bore Stroke:68mm89mm
Compression:9:1
Top Speed:110mph (est)
Power:47bhp @ 6,800 rpm
Transmission:Wet clutch, 4-speed, chain drive
Frame:Featherbed duplex cradle
Suspension:Front: telescopic forks
Rear: swinging arm
Brakes:Front: 8inches drum, Rear: 7inches drum
Tires:3.00x19 front, 3.25x19 rear (UK)
3.50x19 front, 4.00x18 rear (US)
Wheelbase:55.5inches
Seat Height:31inches
Dry Weight:408lb
Fuel Capacity:3.5usgal
Sp:uk
Footnotes:[1] [2]

The Norton Mercury was a air-cooled OHV parallel twin motorcycle made by Norton-Villiers from 1968 to 1970. It was the last Norton model to use the 'featherbed' frame. Following the collapse of AMC and the subsequent formation of Norton Villiers, the company's focus had been on the new Norton Commando. There was a large inventory of parts from previous models that would not be used on the Commando, and to use up this stock the Mercury was conceived. The Mercury was introduced in October 1968 and around 750 machines were produced,[3] most of the production going to the US.[4] The model was also used by the Nigerian Police.[5]

Technical details

Engine and transmission

The engine in the Mercury was based on that of the 650SS,[6] which itself was a development of Bert Hopwood's 1948 500 cc twin first used on the Model 7 Dominator. The pre-unit air-cooled OHV vertical twin engine used an alloy head that was fed by a single Amal Concentric carburettor. A number of internal improvements introduced for the Commando engine were used in the Mercury's engine.

Primary drive was by chain to a multiplate wet clutch and was enclosed in a pressed steel chaincase. The gearbox had 4 speeds.

The machine used 12 volt electrics and was charged by a crankshaft mounted alternator. Ignition was by coil and points.

Cycle parts

The cycle parts of the Mercury were based on the slimline featherbed frame and Roadholder forks. Unique for this model was a humped dualseat. Brakes were 8inches drum front and 7inches rear.

Most of the production was finished with Atlantic blue oil tank, mudguards and chaincases with a silver petrol tank. It was also available in black with a silver or red tank.

References

Bibliography

Notes and References

  1. Web site: 1970 Norton Mercury . Classic-British-Motorcycles.com . 4 July 2021.
  2. Web site: Mercury Rising: Norton's Forgotten Featherbed . Motorcycle Classics . 4 July 2021.
  3. Web site: 1 of 750 – 1970 Norton Mercury . Bike-urious . 4 July 2021 . 28 October 2015.
  4. Norton Mercury . Real Classic . PressReader.com . 4 July 2021 . 4 April 2020.
  5. Web site: Mercury . andover-norton.co.uk . 4 July 2021.
  6. Web site: 1970 Norton 650cc Mercury Frame no. 129398 Engine no. 129398 . Bonhams . 4 July 2021.