Just to throw some more confusion into this, do you pronounce it K0 as in K-ZERO, or KO as in K-OH? (poll). Come to think about it, I use them both, w/o any particular logic. But I never call a sandcast anything other than a sandcast. Dave Edwards had the real nice restored 1970 bike in the Guggenheim Art of the Motorcycle Show back in 2000 in NY and the liscense plate read "K ZERO"
I think the designation K0 logically follows the year. K1's are 71's, K2's are 72's etc. So logically, the more correct term is K0 (zero). Except the K0's made in late 1969, which are known as EARLY K0's. And some people call sandcasts KO's, and some call them K0's. (K-Oh is easier to say, so it caught on for lazy-talking people, maybe).
Then there's ANOTHER group, (a termed coined in the UK I believe) of a short run of transition bikes just before release of the K1, and its also called K0 (zero). This series of just a hundred or so(?) had strange combinations of details like early shark-gill sidecovers, black-ribbed airboxes, linkage dual-cable carbs, carbs, red kill switches, plastic gauges, and ducktail seats. I saw pics in a CB750 Super Profile book years ago. Serial numbers were in the 44000 range if I recall.
