1971 Norton 810cc Commando by Paul Dunstall

The Commando’s vibration-beating Isolastic frame enabled Norton Villiers to successfully prolong the life of their hugely successful parallel twin. The futuristic, boldly styled 750 Commando Fastback was announced at that Earls Court London Show in 1967, the Commando used the preceding Featherbed-framed Atlas model’s 745cc engine and AMC gearbox, and was an instant hit with the motorcycling public, being voted Motor Cycle News ‘Machine of the Year’ for five consecutive years. It might have been a little down on top speed compared to rivals such as BSA-Triumph’s 750cc triples and Honda’s CB750 four, but the Commando more than made up for this minor deficiency with superior mid-range torque and steadier handling.

Norton’s free-spinning 750cc engine acted as a magnet for UK performance specialists, amongst whom Vince Davey of the Gus Kuhn shop and Paul Dunstall – both in South London – were the most highly regarded. Paul Dunstall raced big Nortons from 1957 to 1959 before turning to the preparation of race bikes for others. He was soon offering a huge variety of performance upgrade equipment in what had become a rapidly expanding aftermarket. By 1966 he was building complete machines for both road and track for the princely sum of $1,400.

The 1971 Dunstall Norton 750cc Commando was advertised as “the fastest road machine ever tested in Britain” and quoted a maximum speed of 131 mph, which attracted such customers as Steve McQueen. Meanwhile the racers were campaigned with considerable success including Ray Pickrell’s win in the 1968 Production TT.

As Motorcycle News put it in January of 1969:

With a genuine top speed of 130mph, a twin hydraulic front brake and true, functional good looks, the Paul Dunstall Commando has everything. Dunstall, the customizing king has transformed an unusually good motorcycle into the most exotic road machine available over the counter”.

Apart from the frame Dunstall redesigned just about every component, wringing out 66bhp, 11 more than the standard machine with no loss of tractability. To achieve this, porting was hand-finished and polished to improve breathing, with upgraded valves, springs and guides. Spun cast pistons raise the standard 8.9:1 compression ratio to 10:1. A redesigned “street” camshaft complete the internal attention, while updated carbs, adjustment to gearing, and Dunstall’s wonderfully resonant exhaust helped to get the Dunstall Commando Cycle World magazine’s first ever sub-12 second ¼ mile time, at 107.88mph.

The motorbike offered

Owned by the previous vendor for 32 years, until last summer, the matching-numbers Norton Commando offered here has been extensively upgraded with accessories produced by famed Norton tuner Paul Dunstall. One of the smartest café racers we have seen in a long while, it features Dunstall’s 810cc alloy cylinder block; fuel tank, seat and front mudguard; the very rare twin-leading-shoe front brake; clip-on ‘bars; rear-set footrests; and Decibel silencers. Other notable features include an in-period Churchgate Mouldings fairing with nosecone; Borrani flanged alloy wheel rims shod with Dunlop TT100 tires; Boyer Bransden electronic ignition; Fred Barlow-tuned big-valve cylinder head; 4S camshaft; and vernier-adjustable Isolastic engine mounts. This machine has recently been treated to a complete “nut and bolt’ rebuild to a very high standard by a former Superbike engineer. Only parts of the highest quality have been used and hand finished, while 99% of the fittings and fastenings are stainless steel. In addition, the fuel tank has been treated and is now ethanol-proof. Completed in 2020, the machine a vast quantity of paperwork dating back to the 1980s when many of these special parts were purchased.

The accompanying files from the meticulous previous owner/builder are as follows:

Nuts & Bolts                          Parts Catalogues, Notes
Tyres, Chain & Wheels Parts Catalogues, Reviews, Notes
Shocks & Isolastics    Parts Catalogues, Reviews, Notes on setting up Isolastics
Materials Paint, Gasket Compounds, Adhesives catalogues, letters from Loctite (UK) ltd.
Carbs Amal literature, Notes on jetting 810cc
Hubs Wheel spoke templates, Notes on brakes
Electrics                                 Parts Catalogues, Reviews, Correspondence Notes on electronic ignitions, anti-theft devices, engine plate schematics, frame sundries, fuses, switches, seat, grips, gauges
Gearbox                                 Notes on gearbox
Tools Bearing numbers, literature, correspondence, including the Norton Owners Club
Lubrication Literature and notes on oil and other fluids
Forks Notes on forks, yokes and front and rear hubs
Correspondence Correspondence with previous owners, Mike Nicks, Editor of Classic Bike magazine and Sgt. PJ Evans of Co. Antrim, Northern Ireland regarding brakes
Total Account   Correspondence and receipts, early 1980s, tax discs 1978, 1979
Photos                                   Reference photos
Engine Notes on pistons, casting numbers, clutch, crankshaft, conrods, crankcases, Dunstall 810cc kit, 4S camshaft (deemed “hairy” by a previous owner), and cylinder head