Grease Cups 1915-1923
This type of grease cups was used on early HD forks. They are not serviced like later grease nipples, instead you fill the base and cup with grease and connect both parts by a few threads. Now they work like little grease guns: by twisting the spring-loaded, knurled cup a turn or two after more extended rides you force fresh grease into the fork rocker bushings.
more …