Harley-Davidson Model E - 1936

So William S. Harley, the founding engineer, knew what he was doing when he proposed a new engine design. 

There would be two major changes.  The first involved the lubrication system.  Until that time, most motorcycles had used what's called total loss oiling.  The term misleads.  The oil isn't lost.  Instead, there's a supply of oil in a separate tank.  A pump, hand or mechanical, delivers oil to the crankcase.  Only a few ounces are needed to keep the metal surfaces cool and slick and the pump supplies fresh oil at the same rate it's used, whether burned or leaked away.  Not a bad system when engines run slowly and the pump (or the rider) gets the delivery rate right.  But that didn't happen, so Harley proposed a more modern system, with an engine-driven pump that sent oil to the engine and brought it back to the tank, making sure the engine always had just enough.  Read More...