Factory one was where the all the early 750s were made up to and including the early K1s. This was before Honda realized the demand they had on their hands and built factory two and went into high production. Remember 77000 K1s were produced - more than any other model. I don't know what the cutt-off number is but most of the K1's I've seen are 107xxxx. K0s are typically 104xxxx. Mine is 105xxxx.
Anyway, and I quote
" The Old Factory engines made more power (the ports were being hand-finished and matched), and they had the "good" rocker towers, cams, and a few other internal parts that made them the long-lived champs:
they also had the K0 spark advancers which had more advance angle. It was not uncommon to see over 100,000 miles come from an Old Factory bike, while the New Factory product wore out much sooner."
According to H-man, the only bike that would beat the F-1 K1 was the K0 because they of course made even more power and were hand built with attention to detail in the same factory. I need me a K0 and it looks like you have too many.
How to tell F-1?
"The full-length hand welds at the tank area and the spotwelds in the front cradle where the long slots are (near the steering head section) were the old jigs. On later bikes, the slots up front were shorter and narrower, and the welds by the tank were often not continuous. In the rush to get them built, lots of little things like that started happening in the New Factory."
Once again, H-man is the expert in this area.
