I ended up with a used one from ebay.
DO NOT GET THAT 14MM X 1.5MM, IT DOES NOT FIT. I bought 2 of those, thinking Treats just effed up my order the first time. I must have clicked 2000 petcocks on ebay and Honda's fiches, looking for another bike that might have the same petcock, but gave up when I got this one. Someone at Honda should be able to cross-reference it, or the NU50 is the only bike that uses that one. I find that hard to believe.