Harley-Davidson Styling For 1940

By Chet Billings

From the October 1939 Issue of Motorcyclist Magazine

Styling to correspond with 1940 automotive streamline trends, and refinement of all models to better meet ultra demands for speed, durability and economy constitutes the keynote of Harley-Davidson Motor Company announcements for 1940. As the curtain is drawn back on their offerings for the next year notable features are: instant gas reserve valve; speedlined footboards; chrome nameplates; ribbed crankcase on big twins; streamlined tool box on big twins; tubular front fork on 45 and servi-car; deep-finned aluminum heads standard on 80 twins and 45 WLD, available on 74; front forks heat treated; improved oil distribution in cylinders of 45, 61 and servi-car motors; new big twin crank pin and rollers; cast front wheel brake drum on big twins and servi-car rear wheels; more 61 OHV horsepower; transmission and clutch improvements; copper-flange terminals; improved interchangeable wheel hubs; 5.00x16” tires and rims available; new saddle-top leather; many servi-car advancements; vertical rod antenna and improved vibrator on radio police model; new accessory groups; new color scheme and beautiful color options, and lower prices.

One sweep of the eye tells anyone that the 1940 Harley-Davidsons are new. New colors, deep-finned aluminum heads, chrome nameplates, streamlined footboards, and ribbed crankcases are the first features to catch the attention. Then other items begin to arouse the curiosity; among these are the reserve gas supply control, improved forks, front wheel brake drums, etc.

Let us consider the improvements feature by feature.

For a starter, what is the knurled cap just ahead of the left tank filler cap on all models? It’s a gas control valve that not only shuts off the gas but makes reserve gas instantly available. No more burned hands and fingers as a rider fiddles around hot cylinders in traffic, in the dead of night, or any other time, to turn on reserve gas. When screwed down, the entire gas supply is shut off. When unscrewed to end of thread, the main supply is being used. When that is exhausted, the rod is lifted up and the reserve gas flows on to the carburetor. The reserve gas in the big twins is about three quarts, and about a gallon in the 45 twins. The extended rod is warning that the rider should hie himself to a filling station at the first convenient opportunity. The rod is held in reserve position by a spring-loaded Neoprene (synthetic rubber) packing.

Now riders can really use all their main supply of gas before buying more. Because of the inconvenience of the old system, riders hesitated to get down to their reserve supply, and when they pulled up to a gas station really had to guess how many gallons to ask for. Usually, they ordered too much with resultant gas wastage and the incurring of a dangerous fire hazard.

The entire gas control valve mechanism is enclosed in the left tank and cannot leak. Should it become necessary to do so, the valve mechanism can be easily and quickly removed.

The 61, 74 and 80 twins, which have right and left gas tanks, have their tanks interconnected at the bottom with a looped, standard copper tubing gas line. The same gas level is maintained in both tanks as though they were one. The position of the gas valve controls the gas in both tanks simultaneously.

It’s good-bye to the old familiar tank transfers. With 1940, they are superseded by tear-drop design, chromed, brass nameplates gracing right and left tanks. The front of the plate clips into a bracket on the side of the tanks, and the opposite end is held securely in place with a screw. The name Harley-Davidson is debossed into the plate, and the lettering is red. Two streamlines, one above the name and the other below, are debossed in black and ornament the new nameplates.

A further advantage lies in the fact that there are no transfers to bother with whenever it may be necessary or desirable to re-enamel.

The old familiar rectangular shape of footboards has been streamlined into semicircular design. Not only is appearance served, but in riding position more of the rider’s feet contact the surface of the boards.

The big twins are more streamlined than ever. A look at the gear side of their motors show parallel cooling fins! They add to the appearance of these models and increase efficiency as well. There are eight, one-quarter inch wide, parallel cooling ribs on the 61 OHV and nine on the 74 and 80 twins. These ribs are 3/8” to 1/2” deep on the 61 OHV and 1/2 “ to ¾” deep on the 74 and 80 twins. Strength is added to the case and heat is dissipated.

Another “speed-lined” feature of the 1940 big twins is the tear-drop design tool box with parallel ribbed cover. The new tool box is located on the right side of the rear frame stay. Capacity is ample. The ribbing on the cover harmonizes with the ribbing on the crankcase.

New forks on the 45 twins and Servi-Cars give the front end of these models a new appearance. The new forks are tubular steel, identical in design with the forks that have been used on the big twins. The spring fork is made of seamless steel carbon tubing and the main fork of swaged, chrome-molybdenum steel tubing. The new forks are lighter; and reduced weight, of course, increases handling ease, especially on the solo models-a feature that will appeal to competition riders. Adoption of these new forks also permits the use of the same type handlebars used on the big twins.

Heat treating has always been extensively employed by Harley-Davidson to add strength and service to various component parts of its motorcycles. Now for 1940, additional strength has been imparted to the front forks of all models by heat treating them.

The 80 twins have deep-finned aluminum heads. They are designed to dissipate motor heat, and at the same time add to the general appearance of the motor.

These new 1940 heads made of high Silicon Aluminum Alloy have a 41.5% greater cooling area than the former cast iron heads. They are also 10 pounds 4 ounces lighter per set than the iron heads. The heads are provided with brass, cast-in, spark plug inserts. Brass, of course, is less apt to strip and cross-thread than aluminum. The deep ribs are also cross-finned to prevent ringing.

The 74 twins are regularly fitted with cast iron heads but can be obtained with the above aluminum heads at an extra charge.

The advantages of the aluminum heads on the 80 twins also apply to this season’s 45 WLD. Last year’s WLD Special, announced in the spring, is the 1940 WLD and not only features the aluminum heads but the deep-finned cylinders, large manifold, and large carburetor. Cooling fins on the aluminum heads average 2 inches deep. There are 19 parallel rows of fins on the front head and 21 on the rear head. These aluminum heads have 51.5% more cooling area than the 45 cast iron heads. They weigh 8 pounds and 2 ounces less per set than the iron heads. The 45 twin WL model and Servi-Cars are fitted with iron heads.

Improvements have been made in the 45, Servi-Car, and 61 OHV motors that equalize distribution of oil to front and rear cylinders. The rear cylinder crankcase baffle plate has been removed and the front and rear connecting rods interchanged. Half of the slot on the lower boss of the forked rod has been closed and both cylinders and pistons receive proper lubrication. Two compression rings and a lower oil control ring are used on both the front and rear pistons as well as on the 74 and 80 twins. This cylinder lubrication change is the same that was incorporated in the 74 and 80 twins last year, and all Harley-Davidsons are identical in this respect. The improvement is designed to increase speed, power and motor life.

On the 61 OHV, 74 and 80 twin motor the crank pin has been increased in section from 1 1/8” to 1 1/4”. The number of rollers has been increased from 42 to 54. The more rollers traveling on a larger diameter pin give greater bearing capacity and thus insure longer bearing life.

All Harley-Davidson crank pins, roller bearings and crankcase bushings are lapped to a glass smoothness. Manufacturing practice which only grinds leaves irregular bearing surfaces. Close scrutiny reveals hills and valleys. Without lapping, thousands of miles of road service are required to eliminate these grinding marks. Lapping operations give owners maximum performance from the very outset and greatly prolong motor bearing life.

Now, the crankcase main bearings of the big twins feature a straight-through lap, the same as on the 45 twins and Servi-Cars. This involves a change in the gear and sprocket side crankcase bushings so they can be lapped at the time they are assembled. Perfect alignment of main bearings results, heat is reduced, and bearings are kept from crowding and creeping.

More power has been designed into the 1940 61 OHV. First of all, the bore on the Linkert carburetor is now 1 1/2” in diameter -an increase of 1/4”. The venturi of the carburetor is now 1 5/16” in diameter-an increase of 1/4”. The manifold is 1 9/16” in diameter instead of 1 3/8” as formerly. In addition, the manifold is now T shaped instead of modified Y. It is smooth-bored and gas mixture flows rapidly and easily. Cylinder heads have been provided with larger intake openings to accommodate the larger manifold and carburetor. All these changes bring the gas mixture more quickly and in greater quantity to the combustion chamber, and this, of course, is translated into more horsepower and acceleration.

Rocker arm shafts have been changed so it is unnecessary to make adjustments in order to get the proper amount of oil to the rocker arms. Location of holes in the rocker arm fingers has been changed to insure positive lubrication. A constant, ample supply of oil is assured for the overhead mechanism, and adjustments are eliminated.

The relay base plate on the 61 OHV motor has been redesigned to accommodate the chrome stack on the front exhaust pipe. This gives needed clearance and prevents shorting from the relay to the stack.

Safety will be promoted and better and easier brake action will be obtained with the advancement incorporated in the front wheel brake drum on the big twins and the drums on the rear wheels of the Servi-Cars are made of cast nickel iron instead of stampings. Being cast, and having ample cross section with an integral stiffening ring on the outside diameter, vibration and chatter are eliminated. The inside brake shoe surface is ground absolutely smooth for easy operation. A more efficient braking system results and the rider has a greater margin of safety at his command.

Still another change is being featured in the front wheel brakes of the big twins and the rear wheel brakes of the Servi-Cars, made possible by the new cast drums. As there is no deflection in these new drums, it is possible to employ a 9/32” narrower brake shoe operating shaft. This makes for smoother braking leverage, and it is easier for the rider to expand the brake shoes and make them effective.

Shifting has been made faster and smoother on 45 twins and Servi-Cars by incorporating a spring-loaded ball shift lock in place of the former pin lock. Positions on the shifter drum are easily located. The cam plunger ball is made of chrome alloy steel and is 1/2” in. diameter. Spring tension on the ball can be easily adjusted. This method of locking the shifter drum is now the same as that incorporated on the big twins. The faster, easier shifting of gears that results will be much appreciated, especially by competition riders.

The gear shifter fingers on the 45 twins and Servi-Cars are fitted with rollers which will free their movement on the shifter drum. Slots in the drum have been widened to accommodate the new design. Friction has been reduced, shifting facilitated, and added service has been given these parts. Gear shifter finger design is identical on all models.

To further improve the shifting on the 45 twins and Servi Cars, the clutch release lever has been increased in diameter from 9/16” to 3/4”. Deflection of the lever has been minimized and more of the movement at the clutch pedal is transmitted to the clutch throw-out bearing. A more positive throw out of the clutch is assured and gear wear is reduced.

Smooth clutch engagement in starting and the elimination of chatter are obtained in the 45 twins and Servi-Cars with a clutch key ring that features six inserted flat springs. This design provides a cushion take-up action and prevents the plates from grabbing and rattling.

There are four slotted spring keys on each lined disc assembly in the big twin clutches. These slotted spring keys fit into the keyways of the clutch ring and take up slack and prevent rattle.

A keyed, sprung steel disc is incorporated on all big twin clutches. This keyed disc has been in use for some months. It improves clutch action and reduces chatter.

For 1940, the 61 OHV, 74, and 80 twins will be regularly equipped with four speed forward, all-sliding clutch transmissions. This constant mesh transmission makes possible rapid shifting and is therefore popular with sport and competition riders. To accommodate police and commercial users who are operating in traffic, Harley-Davidson will continue to offer the same three speed, and three speed and reverse transmission, with sliding gear in low gear position, that has been available in the past.

The flange on the drive side of the interchangeable wheel hubs is now a carbon steel forging instead of a stamping. Increase in strength is obtained. This new hub is standard on all wheels except the front wheels on the 45 and Servi-Cars.

Better electrical contact is secured in all 1940 models by the use of new flange-type copper terminals which supplant the usual type soldered twisted wire terminals. Copper metal exerts a tension when placed under pressure which is absent in solder. The result is a contact which conducts the current without loss of effectiveness. These new terminals are used throughout all the models in the line except in the lamps and a few other places where space forbids their use.

Spark plugs for 1940 will be fitted with insulators. The new insulators have been used for some time and have demonstrated that they are less subject to cracking, add to plug life, and help render better plug performance.

The clutch foot lever bearing cover on all models has been redesigned and more securely mounted to prevent noise and rattle.

Brake shackle fork stud on all models is longer and is positively secured with a nu and special lock washer. Lubrication has been made more convenient by changing the location of the Zerk-Alemite fitting.

Stop light is standard on all 1940 models. Formerly it was an extra charge item included with equipment groups.

The regular saddles on all 1940 models are covered with a smooth-finish, full-grain cowhide leather specially tanned. The leather is soft and flexible as well as water-proof and the color is a beautiful brown.

Buddy Seats for 1940 will be fitted with a thick cushion of whipped latex (rubber) . The top covering is the same full-grain cowhide used on the regular saddles. The valance is walrus grain with the back cut out more to give required guard clearance. Three red crystal ornaments decorate the valance. Increased padding in the front end of the saddle gives the rider real comfort when riding two up. When riding solo, there is no tendency to slide all over the saddle.

The high tension spark cable in the 1940 models are made of Neoprene, the oil-resistant, synthetic rubber. This rubber is also extremely resistant to heat. This all means longer cable life.

The sidecar chassis for use with the 45 twins is now fitted with a hinged, rubber-mounted front connection. Riding and handling qualities are decidedly improved.

The front stand on the Big Twins has been redesigned and is now interchangeable on all models.

The new style footboards have made it necessary to redesign both the legshield brackets and the legshields for all models. The new legshield apron gives the rider still better protection.

For 1940, 5.00”x16’” Firestone motorcycle tires are available on all models, including Servi-Cars, sidecars, and Package Trucks. These tires are designed and built for motorcycle use, with ample side and sidewall protection. They allow for adequate fork and guard clearance and add beauty and increased riding ease.

From now on, the 4.50x18” tires that have been available for several years will no longer be furnished, as the new 5.00x16” tires offer so many superior advantages.

Rear and front fenders and the entire tanks are all enameled in the main color with a narrow stripe in the secondary color to set off and enhance the beauty of the chrome nameplates. Color options for 1940 are the following:

Clipper Blue with White Stripe. Flight Red with Black Stripe. Squadron Gray with Bitter sweet Stripe. Black with Flight Red Stripe. Police Silver with Black Stripe (Police only).

The Harley-Davidson plan of offering accessories for new models in groups will be continued. For 1940 there are three groups for solo models instead of two formerly. These groups are:

Utility Solo Group Sport Solo Group DeLuxe Solo Group

The Utility Group offers the minimum in accessories needed for satisfactory motorcycle use. It is a group which will very likely find favor with the purchasers of

Harley-Davidsons for commercial work. The Sport Group will give the rider a dolled-up motorcycle with some chrome flash, yet does not run into too much money. The DeLuxe Group will meet the fancy of the rider who wants the best and all of it he can use to advantage. It incorporates the full chrome group with new style strips on the top of the fenders and chevron on the front fender as well as other items.

By offering three solo groups, it is hoped to meet the requirements of practically all riders so dealers will find it easier to satisfy their demands from their regular floor stock. Other groups are the Police Group and the Utility and DeLuxe Group for Servi-Cars, Utility Group for sidecar or Package Truck outfits, and DeLuxe for sidecar outfits.

The Harley-Davidson Motor Co. announces the following price reductions: the 45 twin with cast iron heads is $5.00 list less; the 45 WLD with deep-finned cylinders and now with aluminum heads is reduced $5.00; the 74 twin is $10.00 less; the 80 twin, now with aluminum heads, is $5.00 less, and the 61 OHV is $5.00 less.

The age old advice is still good. Riders should see the new models to be able to judge them and appreciate what is offered for 1940. Production is already under way and shipments to dealers are started. Visit the nearest dealer, see and ride the 1940 line.

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By Chet Billings
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