Pretty sure the carbs are K2+. The K1's still had brass floats and 120 mains. Maybe K1 carbs if the floats were changed at some point.
The carb chart on HondaChopper doesn't break down the 69-76 carbs very well but I think the floats and jet sizes changed at K2 with the 341 pipes.
http://www.hondachopper.com/garage/carb_specs/carb_specs.html
The jet changes were largely based on the New Factory vs. Old Factory bikes during the K1 and K2. The model 657A carbs from Old Factory had air screws with tiny holes in their tips, and mainjets were #120 until about 11/70 builds or so, when they went to #115. This corresponded to a lesser spark advancer angle. The New Factory K1 had solid-tipped air screws for the most part, with #115 mainjets until late in their K1, when it went to #110 and the needles went from notch 3 to 4 and the floats became plastic. In the early K2 Old Factory bikes, the mainjet was #110 and the needle in notch 4 on model 657A carbs with "holey" air screws and plastic floats, while the New Factory K2 had #105 mainjets and notch 3 with solid-tipped airscrews and plastic floats. By about 3/72 production, all the K2 I saw had #105 mainjets and needles in notch 4, and most carbs had become Model 657B by then, all off which (in my notes) had solid-tipped air screws and plastic floats. This calibration stayed until the end of K5, although some of the K5/6 bikes got carbs with model "7A" stamped on them (but they were otherwise identical to 657B). Oddly, some of the "7A" carbs up through the F0 bikes had brass floats, but also had the fuel valves with the tiny filter screens on them.
There's a couple other carb models in this mix: one is the 087a model, seen mostly on bikes sold in California. They have a larger hole in the little brass orifice in the inlet bell area that feeds air to the pilot (idle) jet, and blunt-tipped, poorly-polished tapers on the air screws, which are (or WERE) fitted with a little plastic cap that was supposed to keep you from adjusting the screw. Most of those I have seen lately have split from heat and vanished, leaving a tiny screw head that sticks out of the carb body and leaks fuel around its edges. The mainjets are #105, but the needle is #271307, being thicker in the lower midrange throttle zone for a lean-burn, low-emission, valve guide-eating smog-controlled CB750 engine.
