Hope this isn't too long a post, but thought it might be of some value to other K0 owners. As part of my "resurrection" project, the carbs needed work, to say the least. Other than needing a good cleaning though, they and the brass floats, hinge pins and posts were in excellent condition. I cleaned them twice (second time with Yamaha, great stuff) and thinking, since I'm in there, might as well install a rebuild kit, Keyster (good place to remember the old saying "if ain't broke, don't fix it"). When it came time to try and get it running, found a couple of issues. One had to do with the Keyster kits. Discovered the high speed needles had a different, more slender profile toward the tip (used a suggestion from SOHC/4 member to use a drill gauge to determine this). This resulted in a richer mixture at the lower throttle openings. The other kit issue I discovered was the little button in the float valve backed by the internal spring was much stiffer on the Keyster float valve than the the original Honda valve. The difference was easily detected by hand. Anyway, I ended up reinserting the Honda float valves and high speed needles. These changes helped.
The second issue was the float height. I set them at 26mm, per the manuals, and measured them I don't know how many times, using a sliding "T" ruler I had picked up at the hardware store. I later picked up a gauge offered by an SOHC/4 member which verified you can accurately set the float height with the sliding "T" ruler, but the gauge has the advantage of letting you see the measurement for both sides of the float simultaneously in case they are twisted. I recall some discussion on an earlier thread as to whether or not the 26mm height actually applied to the K0. I guess I still don't know for sure but I can say on my particular bike it doesn't seem to. I don't know if the 26mm is one of those "starting points" and individual results may vary. After all, the floats are brass with soldered joints. Maybe the amount of solder varies, affecting the weight and thus the displacement when submerged in fuel, who knows. At 26mm I was constantly dealing with some intermittent fuel drips from the overflows, and occasional fuel soaked plugs and running rich. I wasn't sure if it was due to bad float valves (recall I used the originals) or sticking/binding floats. I had them apart several times to recheck and investigate, but everything was fine.
Finally, I decided to change the float height. I frankly took a stab at 28mm or so and the problem disappeared. The carbs were sync'd before this last change, and even though I had to pull the carb tops and slides and remove the carbs to readjust the floats this last time, they still seem to be in pretty god balance, though I will verify. The bike is now running reliably and great.
A minor plug here for the Carbtune. Though the most expensive of the three most commonly used balancing tools, and I'm sure an experienced tuner could do the job with any of them, if not by ear, for a greenhorn such as myself, the Carbtune was just the ticket. No cumbersome mercury sticks (which I'm sure I would break, klutz that I am) and no flutter associated with the vacuum gauges. Nifty tool and very compact.
Anyway, hope this helps anyone else with a K0. And if you already knew this, how come you never told me?
