SPORTING MACHINES ON TEST:
SPORTING MACHINES ON TEST: THE T.T. MODEL TRIUMPH.
By L.A.H.
FOR some years the sporting fraternity have eagerly awaited and hoped for the advent of a Triumph machine on the lines of Victor Horsman’s successful Brooklands racer. The Triumph people, however, have restrained themselves in commendable manner and until the machine has proved, by numerous worlds’ records and races at Brooklands, that for speed and reliability at high speed it was second to none, not a single example of the new engine has been sold. For three years the design was tried out at Brooklands and in the I.O.M. against the cream of the motor-cycling profession, alterations and improvements were carried out until to-day Victor Horsman and his Triumph are regarded as the most reliable combination at Brooklands. Here then is an engine which should be fit for the most exacting rider, and mounted in a frame based on Tourist Trophy experience forms one of the most attractive machines on the market. In view of the fact that this is a distinctly new model it may be advisable to give a brief outline of the specifications :—
The T.T. Triumph has a 2-port roller and ball bearing equipped engine of 80 mm. x 99 mm. bore and stroke, with detachable hemispherical head, tulip valves operated by rockers, mounted in roller bearings, and tubular enclosed pushrods.
An aluminium alloy piston is fitted and the usual Triumph decompressor facilitates starting.
The 3-speed gear box provides ratios of 4.39, (3.52 and 10.19 to 1 and is of Triumph design and manufacture. The frame, forks, wheels and brakes, follow conventional Triumph practice but are adapted where necessary to suit the requirements of a fast machine. On taking over the machine in Great Portland Street we were impressed with the extreme air of solidity of the machine, a trait not entirely unconnected with its weight, which is no less than 325 lbs. However, the primary function of a motorcycle is not to be carried or pushed, though some trials riders might be inclined to think so, and once under weigh the T.T. Triumph handles as easily as any lightweight. A little difficulty in starting was experienced, now and again, during our trial but was usually due to excessive oil it is very easy
to forget to turn off the supply when stopping, with the result that oil continues to syphon through into the engine. If this matter was attended to and once the knack was acquired, starting presented no difficulty, two kicks being at all times sufficient. The engine, fed by a T.T. Amac carburettor ticked over very quietly and with a noticeable lack of mechanical clatter. The exhaust was at all times subdued without being suggestive of lack of power, a feature which enabled fast traffic driving without fear of police interference. On the open road several features became apparent, first that the engine was exceedingly lively and at the same time wonderfully smooth, the only trace of vibration being when 30 m.p.h. was exceeded on bottom gear. The power unit did its work in the silkiest fashion and the whole machine seemed delightfully frictionless and free from any grinding or clattering suggestive of great exertion. Secondly the clutch and gear lever were abnormally light to the hand, a gentle pressure and a slight flick respectively being all that was required to engage a different ratio. The front brake, operated by the right hand proved smooth and powerful but the back brake was the least attractive feature of the particular machine tested. Whether it was some fault of this machine or not we do not know, but the slightest touch on the pedal was sufficient to lock the wheel, even on a dry road. It is possible that the drum was out of truth for the wheel appeared to lock more readily at certain points of revolution than others. One had the impression that the back wheel had a distinct aversion to remaining on the ground and that any attempt at braking only served
to aggravate the matter to the tune of a definite distance, measured in millimetres ! The back wheel did not appear to bounce unduly in the ordinary way even at speed on wavy surfaces, but as soon as the brake was applied and in spite of a good fat Dunlop tyre with plenty of tread it appeared to lose all its adhesive qualities. This impression was heightened by the ability of the engine to cause violent wheelspin when practising “standing starts “on a good surface and a 10 to 1 gear and by the somewhat satisfying sideways twitch of the back wheel when changing gear. On the subject of tyres we are surprised to notice what numbers of manufacturers are fitting the wired on 26 x 3.25 size to sports models. No speedman would think of using such large tyres for racing and from our own experience we are convinced that they definitely do not improve comfort or safety at high speeds. Again, why do so few makers
and talk modestly of 75 m.p.h., a figure which we have no doubt could be amply exceeded by the owner with the most elementary notions of tuning.
In spite of the big tyres steering and road holding were distinctly good, though until the friction discs were tightened, the forks were far too readily driven solid when traversing potholes. We had a very good demonstration of the steadiness of the Triumph when we hit the genuine ” arch-pothole ” and grandfather of all potholes at some 40 m.p.h. It was all over before we had time to ” clutch on,” but the forks bottomed with a terrific crash, both stands clattered down and the machine leapt convulsively several feet into the air. The inevitable lurch, it could not be called a wobble, was immediately repressed by the machine itself before we had recovered sufficiently to realize what was happening.
specify a proper ribbed tyre for the front wheel ? There appears to be some trade reason behind these actions and the Triumph Company err in both respects on the T.T. model, but they are with the majority so we will say no more on the subject.
Apart from these points we have absolutely no further criticism to make of the T.T. Triumph, which we regard as one of the best machines on the market for its price and within £15 either way. It has all the essentials of the simple fast roadster and is not overburdened with the equipment of the I.O.M., Brooklands or genuine touring machine, such as separate oil tanks, large petrol tanks and ponderous silencers on the former types and large mudguards, legshields and carrier on the latter. As hinted above the engine is a genuine offspring of the ” Horsman motor” so far as performance is concerned; the makers make no extravagant speed claims
Cornering was a sheer delight, the machine could be leaned over at tremendous angles with a great sense of security and the footrests were refreshingly high and out of the way of the ground ; a somewhat rare feature on present day machines.
The riding position was comfortable and the location of bars and footrests was variable to suit individual requirements while the Brooks supple seat guarded against saddle soreness on a long run.
As distinct from the brake itself the brake pedal was most excellently situated, it being possible to operate the brake without moving the foot an inch from the rest. A slight rocking motion of the foot being all that is required.
Altogether at 266 the T.T. Triumph is a most remarkable machine, worthy of consideration by the most discriminating of motorcyclists.