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Norton Commando 750

By

Riding Impressions
Norton Commando 750

A 1968 750 Norton Commando.

John H Glimmerveen Licensed to About.com

The Norton Commando was introduced in 1967 to replace the aging Atlas. The Atlas had been a popular machine offering superb handling from its featherbed frame. But Norton came under increasing pressure to improve the power output of their top level machine, and tried to accomplish this by increasing the cubic capacity from its original 497-cc capacity of the early Dominator to 596-cc in 1956 to the 745-cc engine of 1962 for the Atlas.

Unfortunately, increasing the cubic capacity also increased the vibration of these engines to an unacceptable level. The Norton designers decided the only answer was to do away with the featherbed frame, which had mounted the Atlas engine in solid mountings, and replace it with a new design incorporating rubber bushes.

New Frame

The new frame, designed by Dr. Stefan Bauer, employed a large diameter top tube with twin cradle type down-tubes carrying the engine in bushes. The specially designed bushes (Isolastic) were designed to give the engine limited fore and aft movement with little or no sideways movement. Unfortunately the early version was prone to cracking.

Maintaining the correct clearance on the Isolastic bushes is critical to good handling on the Commando. Although the design isolated most of the engine vibrations from the rider, if the clearances were not set properly, sideways movement of the swing-arm (which is mounted to the gearbox) can make the bike feel as if it were bending in the middle.

Right Side Gear Change

The early versions of the Commando were equipped with a 4-speed gearbox with the change on the traditional English right side. Although the gearbox was slightly hard to get into neutral, it offered free and easy changes between the gears. Later versions (1975) were modified to meet the American market by having their gear change lever on the left; unfortunately, the design was poor and made changing and neutral-locating more difficult.

In 1972, the engine capacity was increased to 850 (828-cc) and a front rotor replaced the previous twin leading shoe unit. Unfortunately, many of the early rotor braking systems suffered from poor performance, particularly in the wet. Typically, very heavy lever pressure was required to make the pads grip the rotors sufficiently.

Riding the Commando

Riding the Commando is typical of experiencing any big parallel twin of the period. Good low down torque made initial acceleration strong but the long stroke engine was short on top-end performance, requiring an early gear change to keep within the power band. Again, as with all parallel twin designs not using counterbalance shafts (not available at the time), the Commando rider will feel some vibration through the handlebars and footrests, but considerably less than their competitors, thanks to the Isolastic system.

Another problem with the early bikes was the front forks, or to be more precise: the bushings. The original bushes caused stiction, particularly if the front brake was applied while riding over any bumps. Although the forks always return to their correct position, the point at which they return is unpredictable and varies from bike to bike.

Bottom line is that early Norton Commando is, and always has been, a favorite amongst collectors and enthusiasts alike, but it does have a number of quirky issues that the rider needs to be aware of. When set up well, the Commando is a strong, reasonable handler that generally keeps its value.

Specification:

  • Engine: OHV 745-cc, 4-stroke with two valves per cylinder. Bore 73-mm x Stroke 89-mm
  • Carburetors: Two Amal concentric (MK1) with 30-mm chokes
  • Lubrication: Dry sump, remote oil tank
  • Ignition: Contact points
  • Transmission: 4-speed gearbox with chain final drive
  • Seat height: 31.5 inches (800-mm)
  • Weight (dry) 464 lb’s. (211 kg’s.)
  • Front brake: Internal expanding drum, twin leading shoes
  • Rear brake: Internal expanding drum, single leading shoe
  • Front tire: 90/90x19”
  • Rear tire: 410x19”

Price: An early example (1967) in excellent condition is valued at around $7,400

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