Before 1936, Harley-Davidson motors operated using a “total loss” oiling system. This meant that the oil was never recirculated back to the oil tank and instead it just ended up on the ground after going through the motor. It does pass through the primary to keep the primary chain lubed on the way out, but every ounce of oil you pour into the tank eventually ends up as a trail of drops and drips that leave a greasy trail back to your motorcycle.
Even with oil constantly belching out of the motor, the factory service manual recommends that you change the oil about every 750 miles. In my experience you never reach 750 miles between oil changes, especially if you are using modern oil control rings on your pistons. While using oil control rings sounds like a good improvement, it allows oil to build up in the crankcase which you then must drain more frequently since too much oil creates extra drag on the flywheels. Knowing that changing the oil would be a constant maintenance headache, Harley’s engineers did have the foresight to design the crankcase with a built-in drain to make this a quick and easy job. Located on the left rear side of the engine, a spring-loaded oil valve allows you to drain the oil with just the push of a button.
The oil valve is nothing more than a long rod that goes all the way through the crankcase. At the end of the rod is a round head and a leather washer which press against the bottom of the crankcase forming an oil tight seal and are held firmly in place by a spring at the top of the rod when the valve is closed. To open the valve, you push down on the top of the rod until the end of the rod is sticking out about half an inch from the bottom of the crankcase. A metal catch mounted to the rear cylinder holds the oil valve in the open position while the oil drains.
Once the oil is drained and you have closed the oil valve, adding oil back into the crankcase is achieved using a hand pump which is mounted in the left side gas tank. Unlike most Harley’s, the oil tank on the VL is actually built into the front half of the of the left side gas tank and has two oil lines leading from it to the crankcase. The front oil line goes directly from the hand pump to the left side of the crankcase and is only used for filling the crankcase. The rear oil line wraps around the front of the motor and attaches to the mechanical oil pump on the right side of the crankcase. A VL only needs 3.5 oz of oil in its crankcase, so just three and a half pumps of the hand pump is all it takes to fill it back up.
Since the oil tank holds about a gallon of oil (specifically 9 pints), you don’t have to add oil every time you do an oil change, but it is always good to check the oil level in the tank on a regular basis. When running out on the highway, the engine goes through about a gallon of oil every 500 miles so carrying extra oil is a must. I’m running Motul’s Low Detergent 50 Weight Mineral Oil which is one of the best oils currently on the market. It’s specially formulated for machines built before 1950 and it comes in a 2 quart slim metal container that fits nicely in my saddlebags.
One thing that is important to note is that a lot of people believe that you need to constantly add oil to the crankcase with the hand pump while riding. This is not true and under normal riding conditions you never need to use the hand pump. The factory manual mentions that if you are driving in mountainous terrain you may need to add an extra pump of oil occasionally, but I have not found this to be the case. The cam driven mechanical oil pump feeds oil to the engine whenever it is running and adding more oil with the hand pump only overfills the crankcase. The output of the oil pump is adjustable, so you can dial it in to make sure you are getting just the right amount of oil fed to the engine while riding.
Panhead Jim / @panhead_jim