TEST TIME: HOW THEY PERFORM
by John Brown
The stage one tuned five-speed Gus Kuhn Commando is equally at home on the road or on the race track.
With 6,800 rpm on the clock it went through the speed trap at the end of Snetterton Norwich straight at 133.3 mph but in contrast it was happy to cruise along the M1 at the legal 70 mph with a reading of between 4,200 and 4,500 rpm on the rev counter.
Although the Kuhn Commando, with its 10 to 1 high compression pistons, gas flowed cylinder head, inlet ports bored 2mm oversize to 32mm and oversize 932 Amal concentric carburettors, gave the impression that it was willing to take on all comers in a production machine race, it bristles with features designed to impress the high performance road rider.
Despite its high compression specification, the engine was easy to start. It buzzed happily through the entire rev range without the slightest sign of vibration.
The engine and gearbox units also proved to be extremely oil-tight and throughout the entire test, the only suggestion of leaking oil came from a small seepage from the gearbox end cover joint.
Nothing has been done to spoil the superb road holding and handling characteristics of the Norton Commando. These were enhanced by the Dunlop K81 tyres fitted to the alloy rims front and rear which allowed high speed cornering in complete safety and proved extremely stable during hard braking.
Cornering is further improved by the special high-level Gus Kuhn exhaust pipes and silencers. The pipes tuck further under the machine and at no time was there a suggestion of them touching down.
The upswept silencer units are always well clear and give the machine an extra sporty appearance. While driving the exhaust noise is no more than a powerful burble, and when shutting off, especially in the lower speed range, and accelerating there could be a few raised eyebrows from exhaust noise haters.
The Quaife five-speed cluster fitted to the test machine in conjunction with 21-tooth engine sprocket proved to be hopelessly high for town riding conditions. The too high bottom gear ruined traffic acceleration and trying to find the right gear for town riding was frustrating.
But the gearbox itself was smooth and positive in action with modified ratios should be an asset. The excellent standard Norton four plate diaphragm spring clutch is retained.
It's in the braking department that we come across another of the worthwhile extras on the Kuhn Commando, for while the rear remains the standard seven inch single leading shoe type, the front stopper is exactly the same as used on the Seeley racing machines.
This double twin leading shoe eight-inch unit designed by Eddie Robinson and manufactured by Colin Seeley Developments really comes into its own when braking in the 60mph bracket or over. Below this there is little to choose between the Seeley and standard brakes; but its smooth power promotes the utmost confidence.
The special clip-on and head lamp bracket is both neat and practical. It is quite a simple matter to adjust the handlebar position from normal upright touring position to the dropped racing style.
The easy-to-read Norton speedometer and rev counter are mounted neatly above the bracket. It is also possible to adjust handlebar lengths.
With the clip-ons adjusted to suit personal requirements riding positions of the Gus Kuhn Commando is really comfortable and it was possible to complete long mileage in traffic and on the open road with complete relaxation.
The racing style dual seat fitted to the test model was to say the least a little hard but a double thickness of padding is to be put on future seat units.
The suspension provided by the Norton Roadholder forks and Girling rear units was firm and up to racing standards.
One very useful extra is the three-in-one grab rail at the rear of the machine. This helps to make light work of lifting the machine on the centre stand, can be used to anchor rubber parcel grips or as a safety hold by the pillion rider.
The four gallon glass fibre tank adds further to the distinctive appearance of the Gus Kuhn Commando, an ideal mount for the big bike connoisseur.
AN IMPRESSIVE MILE-EATER
An equally impressive mile eater is the Gus Kuhn version of the Commando S model.
This, fitted with a carefully prepared standard S engine with a 9 to 1 compression ratio and fitted with a similar five-speed Quaife cluster and a 20-tooth engine sprocket, went through the Snetterton speed trap at a creditable 131.4 mph.
On the road the S model proved a little more docile than its highly tuned stable mate, which was a great help in busy traffic conditions.
But there was little lacking when it came to full blooded acceleration and the speedometer rose rapidly as the effortless power surged smoothly through.
With a Seeley front brake and with the Gus Kuhn designed exhaust pipes and silencers replacing the high-level system fitted as standard to the model by the Norton factory, the road going characteristics of the S model were identical to the other Kuhn model.
Alloy rims, the Gus Kuhn clip-ons and lamp bracket assembly are also featured while the smooth appearance of the machine is set off by a Seeley alloy petrol tank, an exclusive addition to the Gus Kuhn range.
The seat from a Norton Commando Fastback is incorporated but another customising extra is a neat rear luggage rack.
GOOD ENOUGH TO WIN RACES
By Martin Hodder
The Kuhn Commando, although a road machine, really comes into its own when its being forced round a race circuit.
The specification is good enough to make many an owner of a big capacity production racer green with envy. And the bike is good enough to wheel straight out for a production event ... and stand a fair chance of winning.
The high compression head and Quaife five-speed close ratio gearbox provide thundering acceleration with a completely standard maximum speed of at least 133 mph. A fairing and even higher gearing than we used at Snetterton would boost top whack to close on 140 mph.
There was no sign of fade from the Seeley four leading front brake, which was more than adequate for the Commando's speed and weight. The standard Commando rear brake was good enough for Snetterton, although it would possibly need some attention for the Isle of Man.
But on the roads even the most demanding owner would be unable to fault either brake.
Steering and handling are excellent, but typically Commando, and I find I have to spend considerable time on the machine before I can use the bike fully. Along Snetterton's Norwich straight I experienced a peculiar rolling sensation which seemed to originate from the front end. The answer to this could be that the Commando is particularly sensitive to slight ridges running along the road surface.
But on all kinds of corner the Commando, with its wonderful K81 tyres, clings to the road and is completely free of vices.
The Gus Kuhn clip-ons together with the seat arrangement and siting of the controls, gives a comfortable position - in the modern style - which is suitable for both road and track use. The stronger rated rear suspension springs, while improving handling, can give an uncomfortable ride on a rough surface.
Unless Gus Kuhn Commando owners intend using them on a race circuit, they're in for a big disappointment. For 50 per cent of the enjoyment comes from the race-bred attention to details, which mostly becomes apparent at speeds well in excess of the legal road-going limit.
ENGINE: 745cc ohv vertical twin, bore 73mm x stroke 89mm, compression 10:1. Alloy pushrods. Built up forged steel crankshaft, large diameter central cast iron flywheel, plain big end bearings, two piece conrods, light alloy high compression pistons. One-piece cast iron cylinder block. Carburettors: Twin Amal concentrics, Type 932.
TRANSMISSION: Five-speed Quaife Four-plate diaphragm spring clutch. Chains: 3/8 inch triplex front, 5/8 inch x 3/8 inch simplex rear.
FRAME: Commando frame with large diameter backbone tube supporting the steering head, twin down tubes anchoring the engine cradle. Swinging arm bolts directly to the engine cradle and not to the frame as with conventional frame design. The engine is fully rubber mounted.
BRAKES: Front, 8 inch four leading shoe Seeley, racing or standard linings; Rear, 7 inch x 1¼ inch single leading shoe.
ELECTRICS: 12-volt battery with zener diode rectification. Crankshaft mounted alternator with capacitor. Seven-inch headlamp.
ENGINE: 745cc ohv twin. Bore and stroke: 73 x 89mm. Compression ratio: 9.0:1. Carburation: Two 30mm Amal concentric. Output: 60 bhp at 6,800 rpm.
ELECTRICS: High output alternator with zener diode regulator.
TRANSMISSION: Quaife five-speed close ratio gearbox, multi-disc clutch with diaphragm spring, primary drive by triple-row chain.
WHEELS AND BRAKES: 3.00 x 19 inch front wheel, 4.10 x 19 inch rear. Seeley twin leading shoe double front brake, 8 inch diameter.