Well, finally had the 68 K0 running so well, I just had to try to drill an extra jet to see if I could get closer to 40mph...  Nope.  Now it runs terrible throughout the rpm range.

I truly think the 4 screw K0 carbs are possessed. Not like ANY other carb when it comes to changes and adjustments.  Even the Suzuki RE5 carb iseasier than this, and they are a nightmare.