My '96 M900 has the vacuum petcock plus an in-line plastic shutoff valve (not sure if they all have this).  As long as I'm good about shutting off the manual valve, why keep the vacuum valve?  Sure, it would shut the fuel off if I crashed and the engine stalled, but I don't see that as a big advantage.  I'm guessing it's there for Ducati liability like the spring loaded suicide kickstands! I have to crank the starter for a long time when the bike sits over a week and I'm assuming that's the vacuum petcock's doing.  Anyone else ditch the vacuum valves?

No need for the vacuum, They are ugly.
I use manual, if i remember. I dont care if its safer if I crash, couse then ill be far away flying from my bike.

I just hate all vacuum working things, thats why I have electric fuel pump and fcr carbs

Uhh sorry blo* job is good

Chances are the vacuum one failed, in the on position, and the PO was just too lazy to remove it.

i dont have a cutoff at all, vacume or manual, i dont see any adverse effects.