Patton wrote:
At risk of stating the obvious, a few wraps of tape dope around the end of the clear plastic tube may tighten the fit....
I got 'er sealed off with _no_ leaks last night. Anyone who is interested, try this. I took a scrap, 20cm, or so piece of clear tubing that was 8mm OD, then put a fast taper on it using a dremmel with a 20mm or so (not critical) grind stone. Then, with only a half twist to thread it into drain port, it didn't leak, plus it held/holds itself stationary.
I only had time to check the carb that I was sure leaked, but sure enough, the fuel level is exactly even with very top of float bowl, instead of 3 or 4mm below it.
The last thing I did before my beauty sleep was to run the overflow tubes from each carb into a separate cup to catch overflow fuel. Now, when I get home I will be able to check each one to see which has a problem.
If you do this procedure, be sure to put bike on center stand then chock/shim front wheel so bowl top is level.