^^^
Thanks for the historical info HondaMan! What manufacturing date was the beginning of what you call "the late K1s"?
ZT
Technically speaking, it was the "New Factory" K1 bikes that showed up with it first, around 2/71-sh or so: the 2nd plant was announced in 10/70, but struggled to get started. Then it spread to the "Old Factory" bikes before the K1 was over (about 10/71 builds is when it ended, and my K2 was 11/71, still with many K1 parts). This is one of the several ways to ID the difference quickly between the 2 factories after Honda opened the 2nd one, due to sales demand.
In the Peoria shop where I worked until 8/71 we had the 2 different types of K1 bikes on the floor (though never for long!). I still remember seeing the 'bumped-in' backsides of the new-style fork ears on the showroom bikes, next to those that didn't have them. That was when I discovered they had both widened the frame stop and indented the backs of the fork ears to prevent them hitting the tank. Unless you were looking for it, the only thing you noticed was how close the fork ears came to the early bikes' tank, and how there was over 1/2" additional space in the later ones: all the fork ears became the later one in the parts fiche (this was/is Honda's "delta parts" philosophy: new parts must fit all the previous ones). One of our sales guys commented something like, "That's gonna reduce how fast you can turn", after which I just shook my head and walked away...