What is the earliest build date known for a complete bike as well as individual parts?
Keith, that is a good question, i don't know that this question has been asked before...
when you say "build date known for a complete bike" what identifier(s) would you look for? as far as we know, the vin tags on RH steering head did not begin until August '69, so as to a build date for a complete bike that came off the assembly line other than a vin tag, i do not know nor have i heard there is a way to determine a build date for the motorcycle.
in the case of identifying exact dates, the only thing i would know to do is to start looking for date stampings. the earlier crankcases did not have sates on them like later cases. if i recall correctly, the waffle cam cover i had, had an ink stamp of 4.3.44, so to my way of thinking this date would be March 4, 1969... keener minds than mine can correct me if i am wrong as i have turned my will and my life over to the madness of the 1927 Harley-Davidson world. (Building a second one.)