The XS 750 uses vacuum petcocks, which means there's no "off"
position, only "on", "reserve", and "prime". Obviously
the automatic "off" is not working. We found out later from
another XS owner that those petcocks can get stuck, especially
on old gummed up bikes that haven't been run in 18 years.
Although the problem may actually be due to the carbs getting
gummed up or the floats stuck, letting the fuel continue to flow
In retrospect I should have fetched a jerry-can and drained
the fuel into it, but being without transportation and late
for work, I left the bike to its own devices.
Sean was kind enough to swing by and pick the bike up. We poured
a bit of fuel in to get a look at the problem, and sure
enough, it started draining out through the air filter. Time
to bring the bike to meet The Barn.