Norton - Vincent
Norton - VINCENT
TONY HOGG
CUSTOM BUILDING of motorcycles is the particular interest of a certain type of enthusiast and, unfortunately, the end result often serves no useful purpose at all other than to boost the constructor’s ego, and, furthermore, it is frequently in extremely bad taste. However, from time to time a machine will appear that is a distinct improvement over the factory product. and a classic example of this type of work is the installation of a 998cc Vincent engine in a Norton Featherbed frame, which was carried out by Pete Adams, a San Rafael, California, motorcycle dealer.
The big Vincents have long been Adam’s first Une because they offer some outstanding features that are unobtainable in other bikes. However, although these machines have many virtues, many felt road holding was not one of them, and it was thi> deficiency that prompted Adams to carry out the conversion.
The engine was taken from a 1954 Vincent Rapide model, and is practically standard except for the addition of a pair of Amal Monobloc carburetors of 1-3/16 inch throat diameter, which were taken from one of the last series of Vincents to come off the line before production was suspended in 1955. The frame is slightly later and came from a Norton twin which probably left the factory in 1957. although the exact year of manufacture of both units can only be estimated from a familiarity with the engine and frame numbers of the respective manufacturers. Anyway, it does not really matter because modifications to the Norton frame were carried out with the main purpose of accommodating different power units, and the Rapide was the basic Vincent engine offered over a period of years.
A cursory glance at the Norton-Vincent tends to give the impression that it is a comparatively easy installation, but this is not the case at all. The Vincent engine can be contained in the Norton frame by cutting the frame tubes, but this would of course alter the geometry and therefore the road holding ability of the Norton, which was one of the prime objects of the exercise. However, the main problem is that, in the Vincent, the engine is slung by its two cylinder heads rather than being mounted on the crankcase in the conventional manner. To solve this problem, engine plates were made up to hold the unit at four points by the crankcase bolts anti, to ensure rigidity, the heads are secured to the two Norton frame tubes by fabricated steel straps. The result is an extremely neat and rigid assembly, which appears to make full use of the available space and will easily withstand the vast torque of the Vincent without pain or strain.
As far as the cycle parts are concerned, they are strictly Norton, and the basis is of course the Featherbed frame which has been around for over a decade, but has yet to be surpassed. In front are Norton Roadholder forks which are an excellent design and a compliment to the frame in every way. In its original form, the machine incorporated brakes from a Manx Norton which are a very desirable feature on such a fast machine but, unfortunately, these brakes and wheels were pirated for another project. However, although the brakes are now the regular Norton road variety, the wheels are equipped with Borrani aluminum rims to provide the best combination of lightness and strength.
Installing a Vincent engine in a Norton frame is not all plain sailing, and one of the complications is the fact that the Norton has its chain on the left and the Vincent on the right, but this problem was solved by simply reversing the rear wheel. Another necessary modification involved the fabrication of a VA quart oil tank which is located under the seat straddling the rear wheel, in the only available vacant space.
At the time the machine was loaned to CYCLF. WORI.D, it w'as lacking a battery and generator. However, these can be accommodated in the normal places, and in all other respects the machine was fully road equipped. In order to enhance the general appearance, some chrome has been added, although not to excess, and the traditional black finish on the Vincent engine has been removed. However, by way of compensation, genuine Vincent handlebars are fitted, and these must surely be the shortest, straightest, and neatest bars ever offered to the motorcycling public.
From observation, the machine would appear to have a very much greater ground clearance than a true Vincent, but actually there is no more than, an extra inch which would probably be used to very good effect by a competent rider because, in a fast turn, the machine will go to an angle which would seem most foolhardy to riders of the standard Vincent.
The power output of the Vincent engine is in the region of 60 bhp, which is not excessive for a 1,00()cc power unit with 9 to 1 pistons, but it is the torque throughout the speed range that makes it a deceptively easy machine to ride. Totally lacking is the buzz of the smaller verticle twin or the thump of the single and, in fact, there is little warning at all that one is transmitting an excessive amount of power through the rear wheel, because high engine revolutions are not a prerequisite for power u'here Vincent engines are concerned. Actually. the machine is a revelation on the road because it accomplishes all it sets out to do. Although at rest it has 'all the weight anti bulk of a very big motorcycle, once under way one gets the impression that this weight and bulk arc being put to a useful purpose, and it is an extremely easy machine to ride provided one exercises considerable restraint.
This combination of Vincent engine and Norton frame is by no means unique: in fact it has been done to order by at least one constructor in Fngland. However, the result is a motorcycle that really separates the men from the boys, and for sheer power, speed, road holding, and appearance, it is certainly hard to beat. •
