Otto, the "upper cylinder oilers" were no joke back then. During the Korea "police action" the quality of gasoline available for general use took a nosedive- - - -all the good stuff was being diverted for military aircraft fuel. Top cylinder oilers were made by the thousands to keep valve guides from seizing up due to fuel-related issues. A lot of them had a tiny copper capillary tube (1/16" OD) plumbed into the intake just below the carburetor, and there was a needle valve on the reservoir to adjust the oil flow. Some of them had 1/2 gallon glass jars for the oil. Dad sold Aviex brand top cylinder oil by the gallon to his customers. The usual metering adjustment lasted about 2K miles (one oil change) between fill-ups of the reservoir.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!