Following the BMW attempt and subsequent others, Velocette held and still hold the record for 500cc motorcycles at the mentioned 100.05mph.
During 1963 they attempted the 24 hour record again with a Velocette 349cc Viper, but suffered defeat by mechanical problems and never tried again.
February 1971 saw Velocette fade from the motorcycle scene into insolvency and oblivion, but not forgotten by a long shot ......
The managing director of Veloce Ltd, Bertie Goodman and "MotorCycling" journalist Bruce Main-Smith headed a team of French riders for the successful attempt and his report in "MotorCycling" follows.
John Griffith, fellow journalist on "MotorCycling" produced a three book series by Temple Press, then owners of "MotorCycling"..."Built For Speed" (1962)...."Famous Racing Motorcycles" (1961) and "Historic Racing Motorcycles" (1963).
I'll feature these in a future blog.
In "Built For Speed" he featured the "24hr Record Velocette 500cc" and his article also follows.
I've included illustrations from these publications below and acknowledge copyright and thanks to Mortons Motorcycle Media UK, current owners of "The Motor Cycle" and "MotorCycling".
Reprinted from " Motor Cycling"- March 23. 1961
OUR 24 HOURS AT 100,05 Bruce Main-Smith on the main straight.....
WELL, we did it! World's Records at both 12 and 24 hour levels have been broken-by driving a virtually " stock Venom” at full bore. Absolutely against the stop, for all those arduous hours, both by day and by night at Montlhéry, near Paris last week-end. For a push-rod " 500 " on a mere 8.75 : 1 c.r. to scuttle round in flying laps of the 110 m.p.h. order, on perhaps the worst track anywhere, is something of which not only Veloce must be very proud but the entire British industry.
The 24-hr. record has not only been wrested from a foreign machine-and by nearly four mph but it has been hoisted to over the 100 m.p.h. mark. If only you could know the appalling condition of the track and the organizational handicaps over which the Velocette triumphed you would realize just what this record means.
As a participating rider, I can report that the machine had to do more than stand continuous full-bore-it had to go quickly enough to make good deficiencies arising front insufficient preparation not attributable, I am glad to say, to anyone hailing from this side of the Channel.
Veloce spent months carefully proving an almost standard “Venom". As any private owner could do, they took it from stock as a normal “Venom Vee-line Clubman," tuned to give both torque and power rising to peak at 5,800 to 5,900 rpm. Using the 1 3/16”in. Amal G.P. as rich as possible, it developed 39.8 bhp. On its 3.92:1 top gear it was able to lap at 110 to 112 mph. which it held for all of every lap-no throttling back anywhere for anything other than pit stopping. A good lap is done in 52 sec. and a poor one in 54½/55.
Now a word about the circuit de vitesse de Montlhéry. It is a bowl-shaped, concrete-banked slice of medieval punishment. It has two minute straights, and two torture-inflicting pieces of bump infested purgatory described as high-speed banking,. On this anti-clockwise course is painted a yellow median line which is the official distance. One must not go below this according to the regulations.
In fact, at 110 mph the line is about the lowest point of the banking at which to ride and during the actual attempt most pilots were about a yard-and-a-half higher to avoid the bumpier track lower down. One is then too high and stays up by leaning over to the right (relative to the banking), which unfortunately hastens tyre wear.
The bankings are concrete, cast in 25-yd. sections. Between some of them it is possible to insert one's clenched fist, often the flat of the hand, and regularly to we see daylight through the gap from the yellow line to the top. The two straights are flat and hardly worthy of the name.
There is a rapid change of contour from banking to straight.
I had under 10 practice laps, of which half were done at night by the standard illumination of 50 car headlamps provided by Marchal ;
the " Venom's " electrics were dispensed with.
This was totally insufficient for an utter stranger to Montlhéry. It was a thoroughly chastened B.M.-S. who came in from his last permitted practice period and I was seriously doubtful of my ability to do more than 10 laps at a stretch, let alone an hour's worth (60 laps). Back at my hotel I stripped off in front of a mirror to study the extensive bruising on the rib cage.
On the strength of the few laps on the second session (in the dark). the riders were selected. the faster ones to be used. They were Pierre Cherrier. Alain Dagan, Bertie Goodman, André Jacquier-Bret, Robert Leconte, Bruce Main-Smith, 55-year-old Georges Monneret and Pierre Monneret.
Pierre Monerett pushs off for a night stint.......
For weeks beforehand it had been insisted that March 18-19 would be excellent weather. Therefore it was not necessary to make use of the perfect days immediately preceding. At 7.30 a.m. it was raining. By 8.27 the attempt was set in motion by Georges Monneret who was supervising matters for the French end.
Georges dashes round in the 51-52 second bracket. His son Pierre takes over and is even quicker. I walk round to the back half of the course invisible to the control tower (a wood intervenes) and study la ligne de Pierre. Riders meanwhile change over every hour and the speed remains well above 105 m.p.h. To run for longer intervals would not be possible anyway with a touring tank of 3.7 gallons capacity.
Dunlop’s Dennis Durbridge wields his depth gauge during pit stops and estimates tyre consumption at two front and four rear, and notes that wear was related to riders. The rear was actually changed at six hours in three minutes. a tribute to the Velocette q.d. wheel system.
At 5.30 Georges is in the saddle again and has some trouble starting. Carelessness in filling the tank from the two polythene buckets of Esso has left a pool under the machine through which the machine’s driving wheel rolls. Consequently, the rear wheel skids.
After dark Alain Dagan takes over and Circulates in 52.8 sec at 107.8 m.p.h. When Pierre Monneret pulls in at the end of his stint, in which the 12-hr. record has fallen, both tyres and the rear chain are changed and I am kitted up to be dispatched. On attempting to select bottom cog for the bump start it is realized that the internal gear mechanism has been bent by some rider stamping on the pedal.
Jack Passant has the trouble rectified and the total deficit is 33 min., all of which I have spent outside in the dark to help the eyes. I hop in the saddle, shout Allez. Allez, the feet of the pushers patter, the motor catches first drop of the clutch and I feed it in doing a cautious entry on to the dark circuit. To save the clutch I drive through the megaphonitis to get onto the trumpet and,
although I cannot see the rev-counter in the track lighting, I know the power comes in at 4,500.
I take it very easily through the gears and hope that the gearbox trouble is nothing very serious and that the box doesn't lock up. As I come down the home straight I am on full song in top and
the motor is running superbly, not a tingle of vibration and giving an impression of utter indestructibility. Frankly, at 110 mph up on the bumpy banking, in the dark on a strange bike and track I am genuinely frightened. The lights at the pits come round amazingly soon on each lap, but the punishment from the bumps is awful. My nose and mouth run on to the chin pad on to which I press my head to keep it behind the screen, through which I look for the entire lap. Through the perspex I can just see the yellow line. I cannot use either the main footrests or the pillion ones properly, but pull a muscle in my right thigh when I try the latter. I try to relax the arms
completely, as Pierre advised me, but find this difficult to do, though I know it is quite safe, for the Velo is steering over the atrocious surface in the way this marque always does, taut, waggle-free, 100% safe. But I have to hold on to the bars for how else to keep on?
The pits signal that my speed is good, but I wonder how long I can stick it. I get to know exactly which bumps will cause the front forks to deflect fully and where these " friends" will be.
Anticipating them with the certainty of their presence I find to be bad and try to forget.
It seems an eternity. I watch a bright star gradually sink below the north-west banking and reason that some slice of time must have elapsed. But how much? The noise from the mega. chases me
round the track like a wild beast. I decide to pack it in. No, keep the British flag flying-show the French that we too can do it. . . . I manage three laps on the patriotism theme. Next I try the Duty to the Readers one. Also good for several laps. Then I’m paid to do this (So help me!)---result, more laps. Then argue with myself about whether I use opposite lock to lift up from the banking. By now (though I do not know, of course) some 45 min. have elapsed. The next problem is the sameness of the course at all points. The rhythm of one's fast, regular, monotonous progress. I realize I am getting hypnotized by the pattern of what I see. I look at the Velocette, the fairing, the red lanterns, the illuminated score- board and the stars,. always coming back speedily to the yellow line 3 ft. to my left under the spinning front wheel.
After 52 m.-some 60 laps that is-I know it would sabotage the attempt if I continued. I come in, remembering the advice to shut off very early because of the misjudgement that results from the monotony of set high speeds. Somebody helps me off the bike as I shout un autre pilot. An English voice says "Good show!” - Mentally I thank him for his kindness. but know that 60 laps is not a full stint and feel that I have let the side down.
Another Frenchman goes out and is pulled in after several laps as not being quick enough. André Jacquier-Bret lasts for 35 laps and retires with eye trouble. Pierre Monneret does a full stint at
172 k.p.h., the scoreboard says. Cherrier tries his hand and after a few 170kph laps gets off the trumpet in a low gear and crawls. He ignores pit signals and after three laps comes in talking of
fog on the course-eyes once more. Georges Monneret fits a stint about here while I cat-nap and he too packs in after half an hour with blurred vision-but he's fast. Robert Leconte, a little slow
it is true. stays on for a long while. At 5.30 a.m. I go on again. Just my luck to get the time of
lowest ebb of one's vitality. I last 30 laps but seek consolation .. in seeing 173, 174 and even 175 k.p.h. on the scoreboard and being officially credited with the fastest night-time lap of 52.4 sec. Bertie Goodman, who has not ridden at Montlhéry before in the dark, sets a formidable full stint of 54-sec. 170-k.p.h. laps. Alain Dagan does yet another hour of rapid, consistent laps.
The piston at strip down, following the succesful attempt.
I watch the official measurement. The engine comes down in perfect shape. I feel damned tired. I make for my hotel and the largest, softest bed they have to offer.
12-hour: 2,021.181 km., 168.431 k.p.h., 104.66 mph
24-hour: 3,864.223 km., 161.009 k.p.h., 100.05 mph
(Subject to official confirmation.)
Reprinted from “Motor Cycling” March 30, 1961
By the time you read these words, the “world's fastest” 24-hour title may well have changed hands again. But if it changes hands a hundred times in as many days the name Velocette will stand out from all the rest, for to this English factory goes the credit of producing the machine that first exceeded 100 m.p.h. for a day - on March 18/19 at Montlhéry track in France.
Last week we carried "Motor Cycling" staffman Bruce Main-Smith's story of his gruelling ride as a member of the record-breaking Anglo-French team. Now we can tell, literally, the inside story of the machine.
And that machine is amazingly close to standard specification-in fact, I would go so far as to say that there are hundreds of " Venom " riders in this country who could have converted (if that is the right word) their stock machines to put up just the same performance.
Let's get it straight. Unless otherwise stated, everything mentioned in this article is STANDARD, either as original equipment or as an optional extra.
Basically, the machine is the equivalent of the production " Venom Clubman Vee-line " model. I say "the equivalent" because the record-breaker was built last June, before the announcement of the production job. and was ready by August, having completed some 1,400 miles at over "the ton" in Practice runs.
The fairing fitted then, specially produced by the Amesbury factory of Mitchenall Bros., was-and still is-the prototype used for the "Clubman Vee-line" models. Why didn't the factory fit a production version for the record attempt? The first maxim of successful record-breaking is to limit changes to a minimum.
The same reasoning applied to the retention of the old-type tank. Both these items had been proved to the hilt and half a yard beyond, and to have carried out similar tests (far more rigorous than those needed for the equipment of normal machines) would only have caused unnecessary delay.
The engine was very carefully assembled and bench developed last June. It had not been stripped-not even the head had been removed until the record was in the bag. Then, of course, it had to be dismantled for measuring. That meant 1,400 miles of testing and 2,400 miles of' record, all at over the "100" mark, without “opening up".
The motor is, of course, on now “traditional” Velocette single-cylinder lines with a gear-driven high-camshaft and short-and so light push-rods; an extension of the gear train drives the magneto, just astern of the barrel. This design, incidentally, was introduced (as a “250") almost 30 years ago.
A Nimonic 80 exhaust valve and EN52 Silchrome inlet valve are controlled by hairpin springs. Valve timing is: inlet opens 55° before TDC; closes 65° after BDC; exhaust opens 75° before BDC; closes 45° after TDC-all checked with .030”. tappet clearance. Running clearances used were: inlet .008”, exhaust .010 “. (just for safety).
Manually controlled ignition is provided by a B.T.H. magneto and, for the record attempt, a non-standard Marchal plug (arranged by the French members of the équipe), was timed at 38° before TDC on full advance.
The Amal G.P. carburetter, of 13/16” bore, has a 310 size main jet-which was too rich, but gave an ample safety margin, even at night. A ¾” packing piece, non standard, was fitted between the cylinder head and carburetter, as it was found to be beneficial when bench tests were carried out. The 1¾” bore exhaust pipe is 34” long and terminates in a KTT pattern megaphone, 12”. long and with a 41” outlet.
Close-ratio gears are used (identical incidentally, with those employed on the last of the factory KTT racers) and sprocket sizes, front to rear, are 23T. 44T, 22T., 46T,. which give a top gear ratio of precisely 4:1. (Even 1 can do this one: gear ratio is product of driven sprockets' toothery divided by product of driving sprockets' ditto 44x46/23x23 =2 x 2).
Dunlop racing tyres were used for the record attempt; actually, Dunlop provided some "special" tyres for early tests but these were found to be unnecessary. Brake lining material is Ferodo MR41, a racing material used on all big Velos, and the wheels had alloy racing rims. Only change to the frame was the addition of a centre stand, to help with quick wheel changes; even the sidecar lugs were left on!
Non-standard also are the rubber-mounted of the oil tank and the float chamber carried front of it ; non-standard is the open primary chain with two-pipe oiler from the engine's oil tank, and rubber-mounted guard which replaces the standard chaincase.
The rear chainguard is retained and the chain is lubricated by the oil-tank breather.
The record machine ran on 94-octane fuel supplied by Esso and multi-grade (S.A.E. 20/40) engine oil. The oil tank was topped up at 4- or 5-hour intervals only to make good the drip to the chain; the oil wasn't changed. S.A.E. 50 lubricant was used in the gearbox.
I asked why 100 octane fuel was not used.
Fuel consumption at a maintained 107 m.p.h. was 35-36 m.p.g. (13½ litres per hour) and maximum speed on the chosen gearing was a shade under 115 m.p.h.
If you want to see the machine, it's on show this week at the Pinks of Harrow showrooms (It was at Stevens of Shepherd's Bush last week-end). It is not far sale. . . .
Printed In England by Temple Press Limited. Bowling Green Lane, London. E.C.I. 7816---61
Engine: Single-cylinder OHV; light alloy head ; 86 mm. bore x 86 mm. stroke= 499 c.c.; c.r. 8.75:1 : 39.8 BHP at 5,900 rpm.
Transmission : Velocette gearbox with close ratios; 4:1 top.
Fuel : 3.7 gal. steel tank.
Oil : 4.5-pint steel tank.
Wheels: Light-alloy rims with Dunlop rating tyres, 3.00”x 19” front, 3.50” X 19” F rear.
Wheelbase : 53.75”
Rear Suspension : Girling hydraulically damped spring units.