Mine just failed a few moments ago. It's in full bypass. I don't know if they are available from Ducati, but I did find one for a BMW K bike that operates at 42psig or about 3 bar.
$89 for BMW part.
Any suggestions?

Preston

More on BMW pumps:
viewtopic.php?f=3&t=3188&hilit=bmw

Did You check fuel pressure by measuring? sorry, i didnt understand, about that "bypass"...

No, it's going straight thru the regulator and returning to the tank at a high volume. . Basically no fuel pressure at the injectors. I was going to try the local Duc shop today. If not there, look at BMW. A 90's model K100 regulator looks to be the same and operates at 3 bar.
Preston

Do U mean, that is coming just after fuel regulator(located iside tank) back to tank, or do U mean, that is coming via return pipe from injectors???? Its normal, that it comes with quite high volume via return line back to fuel tank, as mine works just that way and no any problems. Before You buy any new pressure regulator, measure fuel pressure with adding t-piece and suitable manometer to it. There should be close 3 bar close injectors and all fuel, what they cant use in injectors is coming back to tank via return line....

Antti, the bike was running fine, then seemed to run out of fuel. The return line to the tank from the regulator has as much volume and pressure as the supply line to the injectors has. I suspect this bike sat for years before I purchased it as the fuel in the tank was very bad and the injectors were plugged. I should have replaced the regulator at that time.
Today I am going to attempt the starter sprag. Wish me luck. I am almost to point of selling this bike piece by piece to try to recoup some of my cash if anything else fails on it this week.
Preston

...just my 2 cents worth...

there's not much to "fail" with the regulator...maybe could get stuck if grit got in but that's about all...
this is unlikely unless the filter was not in line (and I have had a filter FULL and I mean full of rust)...they operate well even when you think they would be clogged.
the line flow back to the tank is quite high - particularly if the pump pressure and rate is higher than the fuel consumption.

I'd do a pinch test on the fuel delivery line out of the tank.
you should be able to feel the line go hard when it pressurizes as you turn on the key and the pump operates.
the pressure will bleed down after a minute or so...but it's an easy test to check for fuel flow and pressure regulation.
if it goes soft quickly it would indicate pressure loss in the line...or perhaps at the regulator.

on an older bike I'd check for a blown hose INSIDE the tank; happened to me..nearly impossible to track down...

Have You changed fuel filter? Sounds little clogged filter... If bike have sit long time, i would take injectors to maintainer also.

could be a split filter i have had this happen biffo

actually the regulator is the only component in the system that had not been replaced. I had the injectors rebuilt 2 weeks ago, new fuel pump and all fuel hoses replaced with a new filter. Also did the POR 15 treatment to the tank. I think this bike must have sat for a number of years to get in this shape. Anyway, I replaced the regulator this afternoon, and all is good again. Took it out for a short ride and I think the bike was as happy as I was.
I am riding it to Big Bend next weekend, which is about 500 miles from my home. I have faith in her. If any one wants to meet up there, let me know. I'll be in Sanderson, Tx Friday night with about 25 others.
Wish me luck,
Preston

great news that the regulator was easily replaced...
you were lucky to pick up a spare...

I'd be very interested if you have time to disect the old one and see what or why it failed.

the whole operation of the 907 is based on maintaining 3 bar fuel pressure; if the regulators are unreliable for any obvious reason it wll be handy to know what gives out and perhaps be able to prepare for replacements or modification...

my guess is the POR15 treatment has somehow seized the piston.

I will attempt to take it apart when I get back. I took it for a ride this evening, about 15 miles, and all is good. Got home with no oil leaks, and no coolant leaks. Starter works fine, and it is charging, but the light is still on. I'm going to disregard the light for now. I took it to the local Honda dealer to get the state safety inspection, and those guys couldn't get enough of it. I'll let you know how it does over the weekend. This will be about a 1500 mile ride round trip with some great roads to really exercise it on, and smoke some Hondas

The Honda CBR 1000 coolant neck and Kawasaki KX250 coolant bottle seems to be working fine and it all fit with out any modifications to the bike.

Preston