Tough to find, don't have any yet.
The New "De Luxe" Henderson October 6,1921
"A New "Four" Model Bristling with Refinements, Combining a Super-Speed and Ultra-Flexible Motor; a New and More Powerful Braking System; a New Saddle and Improved Mounting; New Light Control, Etc.
A NEW model which has just arrived with unusual and startling claims for distinction and favor is the new Henderson "De Luxe" model, which the Excelsior Company claims is the world's fastest road machine.This broad claim is backed by the speed demonstrations of Wells Bennett and Roy Artley on the Pacific Coast. All the salient features of the machine used in these speed tests are embodied in this new Henderson model.
Speed makes the essential appeal to many motorcycle riders. Even though they may seldom ride wide open, they like to know that reserve speed and power are there. They like to boast to their friends what their machines have done and can do, and when the claims are doubted, they like to go out on the road and demonstrate that they have the goods. And when extreme speed is combined with the surpassing smoothness, responsiveness to the throttle, flexibility, ease of handling, and quiet running, the result is a model which makes an irresistible appeal.
The speed pedigree of this new Henderson model has been established by the speed demonstrations mentioned. The history of the development of this machine makes interesting reading. Several months ago. Wells Bennett started things moving by romping over California pavements on a Henderson at unprecedented speed, for the edification of the Police Departments in different California cities. The performances were not record trials in any sense—Bennett was merely showing the doubters— and there were plenty—that a Henderson could do ninety miles an hour and better.
The first test was made at Ventura,May 12, 1921, where Bennett piloted his fleet "Four" through the regulation speed trap at 90 miles an hour. Following that, Wells regaled the Police Departments of 25 other cities with speed bursts of 90 miles an hour or better on the road. The most recent test was made at San Francisco a few weeks ago by Roy Artley, in which he attained the unparalleled speed of 98 miles an hour with the machine carrying its full road equipment, including generator and lights.
This particular Henderson motor was designed and built in the Excelsior factory and shipped to the Henderson Motorcycle Sales Co., at Los Angeles, in November, 1920. California was selected as a test ground for the new "De Luxe" model because of the many miles of excellent pavement and the Beverly Speedway conveniently located near Los Angeles. Since that time, the machine has been in almost constant service in sidecar and solo use of the hardest possible description. It has been entered in numerous competitions, including hill climbs, endurance runs, etc., to say nothing of the speed tests by Bennett, Artley, Mattson and others. Altogether, the machine has covered more than 16,000 miles. It is still going at a lively clip and constantly improving.
Back of this Henderson is a lot of painstaking development work by the Excelsior factory, with the final adjustments and finishing touches applied by Allan B. Monks of the Los Angeles Henderson store. Both the factory and Mr. Monks had well-defined ideas that a lot of velocity was packed away in the Model K Henderson, which had not previously been given a chance to assert itself, so the factory set about methodically to speed up the machine, not for a racing or road-record campaign, but to demonstrate its inherent speed possibilities. Experiments were tried, and slowly and surely, the machine commenced travelling faster and faster. Greatly encouraged by the results of the experimental work, it was finally decided to make a real test.
One day, not so very long ago, Monks, Bennett, and a select audience quietly assembled at the Speedway with an assortment of trustworthy stop watches. After preliminary adjustment and warming up, Bennett finally "turned everything on" and commenced the celebration with a lap at approximately 87 miles an hour. On further laps, the motor performance improved, and on the fifth circuit of the track 90 miles an hour was registered and everybody was surprised and elated.
Then came a little further adjusting, and the machine was taken to Ventura and put through its paces before the motor "cops" of that place and Santa Barbara, with the officers themselves holding the watches. There Bennett repeatedly went through the regulation speed trap at 90 miles an hour and better. Before witnessing the test, the officers had good-naturedly scoffed at the ambitious speed claims for this new Henderson, but, after the demonstration, they were convinced. Further testing and demonstrations then followed before the police of Huntington Beach, Santa Anna and San Diego. At the latter place, Bennett shoved the miles per hour up to 93, timed by seven watches in the hands of city and county officers.
Then Monks had a natural curiosity to ascertain what the machine would do with a sidecar and passenger. Accordingly, he made a trial over a measured mile, which he covered in 43 2-5 seconds, representing 83 miles an hour.
In all of the development work on this "De Luxe" model, the Excelsior factory made no attempt to introduce innovations foreign to Henderson design, or in any way calculated to impair the rugged strength and durability of the machine. No features were considered which were impracticable for ordinary every-day road use. Every effort was concentrated on adding finish, refinement, balance and reliability to the power plant. No special camshaft was used because the stock cams were found far superior to any other practicable contour.
A fact noted and commented upon by many people who saw the motor travel and examined it afterwards, was the wonderful cooling of the engine. Apparently, the faster this type of motor runs, the cooler it operates. After ten miles of running with wide-open throttle on the Los Angeles Speedway, the cylinders were cool enough that a hand could be placed on them without discomfort.
Another striking point in connection with the machine is the fact that it is a real road outfit in every sense of the word. During Bennett's many demonstrations, he took the machine over the road under its own power from town-to-town, often with a sidecar attached, whereas, special racing machines are invariably delicate and cannot be run over country roads. They are entirely impracticable for anything but racing.
Observing the new "De Luxe" model Henderson for the first time, one is immediately impressed with the harmony, symmetry and suitability of the job. Each and every part is obviously designed to harmonize with the others. The lines of the machine are graceful and attractive.
The lower center of gravity is at once apparent, for the motor is mounted a full inch nearer the ground than in any previous Henderson model. Drawing an imaginary line between the axles, it is evident that the heaviest part of the power plant is below this center line. This new mounting of the motor is effected by a new, lower and wider frame. The lower cradle tubes of this frame are one inch wider on either side, and the power plant is supported on lugs on the inner sides of these cradle frame tubes. Formerly, the lugs supporting the power plant were mounted over the centers of the lower frame tubes. This lower center of gravity is particularly noticeable when you first climb into the saddle. There is none of the top-heavy feeling experienced with some machines. This lower mounting makes the machine remarkably easy to balance and holds it to the road at high speed.
A further improvement in riding balance, which, at the same time, conduces to comfort and safety, is effected in the new saddle. This saddle is of an entirely new type and has a larger and more comfortable top. The riding position is extremely low, and even a short man can place both feet squarely on the ground. The saddle is really built-in as part of the machine, and the mounting dispenses with the usual saddle frame. A much wider yoke is provided across the rear forks to support the springs, and the great width of this yoke makes for stability and does away entirely with the dangerous and objectionable side-sway. The fulcrum mounting for the front saddle extension has been moved farther forward, giving a much longer radius of saddle movement, which affords practically a straight up-and-down movement of the saddle. The springs are of the new extra-long, anti-recoil type, which absorb all road shocks and entirely eliminated bouncing and slamming the rider on rough roads, thereby greatly increasing comfort and safety. This new Henderson saddle, although simple in construction, is one of the greatest advances that has ever been made toward riding comfort and safety.
The principal change, of course, is the new Henderson "De Luxe" power plant, so-called because it is, beyond a doubt, the mostly highly developed and advanced engine ever built into a motorcycle frame. The most noticeable external modification is the adoption of the new straight-down exhaust pipes which follow down the side of the engine and curve gracefully at their lower ends where they blend into the combined muffler and tail pipe below the foot-board. This muffler is provided with a cut-out operated by a conveniently located lever. When the cut-out is open for high speed work, there is a direct exhaust passage to the atmosphere with no back pressure or restriction. Most riders are keeping their cut-outs closed around town these days, but nearly all of them like to hear their motors "talk" in the open country, and the rhythmic purr of the Henderson motor, even with the cut-out open, is in no way offensive.
A real "stove" is combined with the carburetor in conjunction with the rear exhaust pipe to pre-heat air for the carburetor intake, and this preheating arrangement is more effective than any previous attempts along this line. The stove is a cylindrical compartment, several inches long, open at either end, encircling the exhaust pipe. The main air supply for the carburetor is drawn in and over the surface of the hot exhaust pipe. This feature will be found a distinct aid iii vaporizing present-day low-grade gasoline.
The motor is of the high efficiency, long-stroke type, with 2 11-16 inch bore and 31-2 inch stroke, giving 79.4 cubic inches displacement. Extreme care has been given every detail of design to produce the highest degree of efficiency, pep and pulling power. The intake manifold has been materially enlarged with sweeping intake passages to facilitate filling the cylinders, and to distribute charges equally to all the cylinders, which is an important factor in flexibility and smooth running at all speeds. The cylinder design of the special "De Luxe" model has also been changed. Larger intake passages into the cylinders have been provided, with the least possible restriction to impede the passage of gas charges. The exhaust passages have been correspondingly enlarged and improved.
The Henderson force feed oiling system has been so highly developed that the only attention required on the part of the rider is to maintain a proper supply of oil in the crank- case sump. The oil is circulated by a positive gear pump through pipes and ducts into all the crankshaft main bearings and through the hollow crankshaft into all the connecting rod bearings, maintaining motor efficiency in extra hard service and altogether preventing wear. Detail refinements in the oiling system of this "De Luxe" model, to provide for the increased speed, also insure perfect distribution of oil to all bearings and cylinders, and have reduced oil consumption fully 106%.
All interior motor parts are oversize and have a great factor of safety. There has been an erroneous impression that four-cylinder machines are necessarily more delicate than twins.
The crankshaft bearings are 1 1-4 inch in diameter; the connecting rod bearings are 1 1-4 inch in diameter and 11-8 inch long; the wrist pins are 5-8 inch in diameter, and the wrist pin bearing surface in the pistons on either side of the conneting rods is 1 3/8 inches.
The Henderson side-by-side valve arrangement is retained in the "De Luxe" model because of its compactness, accessibility and general suitability.
Another very valuable feature of the new model is the new braking system with practically double the former braking surface. This greatly increased braking surface will make it possible to bring the machine to a stop within a much shorter distance,and will largely obviate sliding the wheel with its consequent tire wear. The maximum stopping effect with any brake is attained just before the point where the wheel is locked and slides. When the wheel starts to slide, the braking effect is greatly reduced. Previous brakes have not had sufficient surface to absorb the energy stored up in the moving machine. This new brake has ample surface, and the new internal expanding brake is as effective as the external contracting band.
The outside band is 11-2 inches wide. It is anchored in the center on a coil-spring cartridge mounting. On top is an additional spring support to hold the band away from the drum and prevent drag. This top mounting works in a slot to enable movement of the band when the brake is applied. Both ends of the band are drawn together in action, making the brake every bit as effective forward as backward, which is also true of the new internal brake.
Adjustment of the external band to compensate for wear of the lining is readily effected by an ingenious new device arrangement. The device bolt is fastened to the lower end of the brake band by a cross pin and cotter pin. It extends up through a cross pin in the upper end of the brake lining. On the end of this device bolt, fits a cap screw, the lower end of which is milled out to conform to the rounded surface of the upper cross pin. Obviously, to tighten the brake, it is only necessary to turn this cap screw and the adjustment is maintained by this positive looking device.
The new internal expanding brake is also correspondingly larger and is rendered far more effective than the previous internal brake because both ends of the band are spread by a cam arrangement and forced to conform to the surface of the interior of the brake drum. In the former internal brake, one end of the band was anchored and the other actuated by a lever. This new internal band, which is made of the best quality spring steel, is supported on a pin in the center and a strong* spring contracts the ends of the band when the brake is inoperative, preventing dragging.
This new braking system is unusually powerful. The action of the brake is smooth and sure'. The rider of the "De Luxe" model is reassured by the thought that he has two equally powerful brakes on which he can rely absolutely in any emergency. Furthermore, when the brakes are "off" the rear wheel is altogether free and there is not the slightest dragging.
The battery box is mounted in a substantial manner directly over the transmission case and use of the straight-down exhaust pipes makes the battery readily accessible for periodically adding water.
A new Cutler-Hammer, automobile type, lighting switch is used with an integral built-in fuse block. This switch is mounted on the side of the battery box and is entirely self-contained and weather-proof. All the lights are controlled by pulling out or pushing in a small nickel-plated knob Control of the dimmer light is by a convenient and durable switch built into the headlight.
This new "De Luxe" model offers the very ultimate in motorcycle value, combining all the excellent features of the regular model with the many additional refinements and improvements. It is offered at $50 advance over the regular model Henderson, which makes the selling price $525 f. o. b. factory."
The Motorcycle & Bicycle Illustrated, October 6, 1921.