|Veloce Managing Director Bertie Goodman on the 24-hr record attempt Viper|
Both attempts took place with an Anglo-French team at the Montlhéry speed bowl, a 2.7km concrete track (still extant, although perhaps not for long... this track is as historic as Brooklands, and must be saved!), with a notoriously bumpy surface (to which I can attest, having blasted a MkVIII KTT Velocette on the banking in 2000), and rather poor facilities, especially track lighting. Obviously, if a machine is to be run for 24 hours, the track needs to be lighted, and Montlhéry is distinctly dark at night, being outside the small suburb, and in a forest. Both attempts used rows of parked cars with headlamps ablaze, to light the track at intervals - notably dangerous when you consider that each 'beam' was a perpendicular flash of light at 100mph, creating a dizzying stroboscopic effect. During the earlier Venom 24hr ride, a French rider became so disoriented late he ran off the track, derailing the whole exercise for half an hour, while the machine was sorted out. The team still had time in hand, and just squeaked over the magic 'ton', at 100.05mph for the 24 hours.
| Georges Monneret, many-time French national racing champion and veteran of |
the 1961 24-hr record, adjusts his goggles, as dealer Reg Orpin and
rider Bertie Goodman look on
|Bertie Goodman prepares to push off for a stint|
The Viper was more comfortable than the '61 Venom, as the front forks now had both compression damping and rebound damping; this 'extra' was recently introduced to their sporting 'Clubman' models, and really helped over Montlhéry's bumps. The steering and true-running were faultless, even when airborne over those bumps at over 100mph.
The machine was geared to reach 110mph (176km/hr) at 6500rpm, and after 6 hours, the Viper had an average speed of 104.7mph; faster thus far than the '61 Venom. The hourly average, excluding pit stops of 75 seconds each, was 105.1mph, which was fully 23mph faster than the existing class record, established in 1961 by a 175cc Bultaco two-stroke.
The following is the verbatim text from Motor Cycling, July 17, 1963, written by Bruce Main-Smith, who joined in the attempt:
|Journalist and publisher Bruce Main-Smith 'down to it' on|
the concrete banking of Montlhéry
Up to that time, the hourly average-excluding pit stops of about 75 seconds each-had been no less than 105.1 mph - 23mph up on the 24-hour class figure established by a 175 cc Bultaco in 1961.
The “Viper” was running with complete regularity and seems ready to equal the 'Venom’s' 24-hour 100.03 mph of 1961. It was, in fact, improving slightly on the '500's' speed.
However, the second attempt, started at 10.40 a.m. on Sunday, failed after 1 hour 44 min. at an average of 102.5 mph with suspected gudgeon-pin fracture which it was quite clear that factory mechanic, Jack Passant, could not remedy in time to keep the average above 100 mph.
The 'Viper' was permanently disabled and the extent of the damage cannot be determined until the head and barrel are lifted at Hall Green later this week.
As No. 3 rider, I took over in the first attempt after veteran Georges Monneret had done a 1 ¼- hour stint and Veloce sales director Bertie Goodman had put in 1 ½ hours-an endurance close to the limit of the 5 ¼-gallon tank.
Better than the ‘Venom’
The engine was running perfectly with no trace of vibration. Navigation and line-holding when airborne over the ripples were dead accurate. Comfort over the appalling Monthery bumps was much better than on the “Venom” in 1961 – apparently owing to improved front-fork damping on the impact stroke.
Rider fatigue was minimized by a specially-prepared “Avonaire” fairing which, I was told, added between 6 and 8 mph to the “Viper’s” maximum, depending on the rider’s stature and his ability to get in behind the dolphin. And taking over from me, ex-French champion Benjamin Savoye averaged 109.6 mph with complete consistency and no sign of the motor tiring.
The “Viper” showed no signs of overheating, in fact a deflector plate was fitted to the air intake to raise the oil tank temperature after it had proved to be on the low side in practice.
Magneto failure was about as close to bad luck as you can come in competitive events. On the other hand piston failure is never unexpected in high-performance work of this kind. During the magneto replacement and general adjustment session the inside of the head revealed well-nigh perfect carboration erring--if that’s the word—on the rich side.
A 10:1 cr piston, specially made for the job, was used. With the megaphone and sodium-cooled exhaust valve, it was one of the few parts that are not available to any Velocette owner from the factory’s stores."
Many thanks to Dennis Quinlan for vital information and photos; data also taken from 'Velocette Production Motorcycles' (Walker), 'Velocette Motorcycles' (Burris), and 'Technical Excellence Exemplified' (Rhodes).
(Click here for the successful Velocette 100mph/24hr ride in 1961)