Paul,
don't know what type you have, please specify
For my 550 K1 - NOS 16950-374-671 with dual output are really expensive. For the first try I first get NOS with sigle output but after some time started to leak after ~1 month. Then I bought replica one from 4into1
https://4into1.com/petcock-20mm-x-1-5mm-16950-374-671-cb550-1975-1976/. But even this started to leak after few weeks. I now suspect root cause of this is degrading kreem liner in my tank (PO applied it wrongly on corroded surface) that decomposes into particles, some very small (like small sand grains) that passes via strain to petcock (and make it leaking) and then reach carb float valves (blocking them to close). All in all, I have petrol leak in garage floor
... My next step is to remove liner from tank and remove corrosion.
Pics are showing what comes out of tank each time I flush it and how it looks like inside...
