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                             Harley J, JD, & JDH
                Motor Lubrication, Mechanical Oil
                    Pump, Motor Care and Repair

                                   What Perfect, Motor Lubrication Means

The Harley-Davidson oil pump is designed to feed just the right, amount of oil to the motor. With oil in the tank, a scarcity of oil in the motor is impossible. Neither can the pump feed an oversupply when properly adjusted. This makes for great economy.

     More advantageous than this economy of oil is the fact that perfect lubrication eliminates excessive, carbonizing of the motor and all the attendant evils. Strange as it may seem at first thought, too much oil, w while not so serious as an undersupply, will eventually wear out any motor. Harley-Davidson engineers found .that that the only way to prevent an oversupply was to lubricate the motor by an 'automatic mechanical driven pump, with a large, positively operated, rotary valve working independently of temperature conditions.

On the subject of over oiling we want to call attention to the fact that it is not necessary to have blue smoke at the exhaust to indicate that the motor is receiving sufficient oil. There may be an oversupply of oil in the crank case and; the motor not smoke. Too much oil in the crank case will cause loss of power and speed due to the overheating of the oil. Read carefully the instructions on the adjustment of the mechanical oiler and the use of the hand pump.

            Serious Results of Excessive Lubrication

     When a motor becomes carbonized, tiny particles of carbon gradually work into the cylinder walls, piston face and piston rings, acting as an abrasive, eventually causing wear to these parts.
Some of this carbon works past the pistons into the crank case, where the circulation of oil carries this destructive mixture to other moving  parts. If the rider neglects to flush out the crank case occasionally, this mixture of fine carbon and oil causes the cylinders, pistons, rings, bearings, crank pin, crank shafts, gears and valve action to wear excessively.
     Much so-called "motor trouble" is caused by improper carburetor adjustment. To offset the poor running of the motor, due to heavy oil vapor in the combustion chamber as a result of an over-supply of oil, the rider will adjust the carburetor so that it feeds an excessively rich mixture to the motor. This mixture not only rapidly deposits carbon, but makes a
slow burning or poorly combustible gas, tending to overheat the motor and causing a material loss of power. The rider in attempting to remedy this overheated condition will give the motor more oil, making matters worse than ever.
     Summed up briefly, proper lubrication means sustained speed and power, and prolonged motor life. It means a uniform gas mixture and the end ai most so-called "motor troubles," due to fouled spark plugs, burnt, pitted or warped valves which are often the results of an improperly adjusted carburetor, furnishing too rich a mixture to offset the effects of too much oil.
     From the foregoing it is clear that too much oil is almost as serious in its effects as not enough oil. It has usually been taken for granted that as long as a motor received enough oil it made little difference whether an oversupply was used. This is positively wrong. Not only is excessive lubrication expensive from the viewpoint of the cost of the oil itself, but from the standpoint of motor service and life.
     The Harley-Davidson mechanical oil pump makes it possible to adjust your oil supply to a nicety; to use just enough oil, not too much, nor too little.

Use of Hand Pump

Occasionally it is advisable to give the motor a little extra oil by means of the hand pump when speeding, negotiating a long steep hill, or when going through long stretches of heavy mud or sand, especially if the machine is carrying a sidecar and an extra passenger.



Illustration No. 12
             Sectional view- of Automatic Oil Pump.

             Operation of Harley-Davidson Automatic
                               Mechanical Oil Pump
(1915-1929 Model J, JD, JDH)

     The Harley-Davidson oil pump has no check valves to stick, no ball valves to "float," no valve springs to break and no small parts to go wrong.
     In illustration No. 12 the rotary valve member R rotates in a left hand direction, looking at it from the top.
    After the cam H has raised the plunger P to its highest point, the spring Y returns the plunger, drawing a charge of oil from the tank through the supply pipe S, and through the intake system as follows:
    Through the channel L, oil reaches the intake port I, in the valve chamber. The port I is connected with the hollow center C of distributor R. From C the oil passes through the opening A into the distributor channel X, then through channel B to pump chamber T.

     Just after the completion of the intake stroke of the plunger P the intake port I closes and the discharge port D opens, lining up with channel E. As soon as the plunger is raised by the cam I-I, the oil in chamber T is discharged through the channels B, X, A, C, D,  (D is now opposite E), E and F to the sight feed. From the sight feed the oil is forced to the motor through opening G.

     Although the highest crank case pressure registered to date in any Harley-Davidson motor tested was 4 pounds to the square inch, the Harley Davidson oil pump will operate against a pressure of 70 pounds if necessary. It is absolutely infallible in its operation. There are no small parts to break. The pump has but two moving parts, the plunger "P" and the distributor valve member "R," rotated by a worm gear made integral with one of the gears.

To Adjust the Automatic Oil Pump

     When each motor is tested at the factory the mechanical oiler is adjusted so as to give the proper oil supply at speeds up to 45 miles per hour. With this adjustment a hial.f pint of oil will average approximately 45 miles (720 miles to the gallon), if Harley-Davidson cylinder oil is used. This adjustment. as it leaves the factory, is such that plenty of oil will be fed to the motor and should not be changed excepting for good reason.

     When the machine leaves the factory the mechanical oil pump is not fitted with any definite number of washers at 'K.' The number of washers varies, depending on the amount required to give the plunger %2 inch stroke.
If, for good reason it is desired to decrease the oil supply, remove one thin washer. The adjusting screw "J" regulates the stroke of the oil pump plunger and should be securely tightened after adjusting.
     When all the washers have been removed the plunger has no stroke, and nothing can be gained by counterboring the cover or adding to the length of the screw.
In the tool box will be found two thin washers, each .013 inch thick and two washers each .065 inch • thick. To increase the oil supply, add one of the thin washers at a time to the standard washers with which the machine comes from the factory, until the proper oil supply is obtained. Be very careful not to reduce the oil supply below the safety margin. It is better to feed a trifle too much oil than to run the chance of underoiling, but an absolutely correct adjustment can be made, and should be.