Can I just clarify, do you think there is a problem with my fuel pump because of the rapid rate of pumping and the fact it doesn't cut out as the pressure builds up. If that is the case then do I just not need to replace the pump.
However, if the pump is meant to pump rapidly and does not cut off when under pressure then I can see the rationale behind fitting a regulator.

I read somewhere ( only someones opinion ) that the pulsing of the reciprocating pump was a large part of the problem with webers on paso's because the peak pressure of the pulse was enough to overpower the float valve , hence the return line . Almost all of the cars I can remember that have had a mechanical fuel pump ( pulsing pressure ) have this return line set up , and most of the set ups with a rotory pump (constant pressure ) have a regulator , I cant see how a regulator could be expected to regulate something that is fluctuating wildly between 0 psi and whatever , how is it going to provide an output pressure of say 3psi when the supply pressure drops below that Im sticking with my rotory pump . Ha , I know a guy who built a hot rod ( 38 Chev coupe 350cid v8 ) and being a tight arse ( he is a scotsman ) decided that pinching a load of 1/4" steel tube from work was way better than buying the required 3/8 fuel line, he would not be told ..... by anyone ( did I say he was Scottish ) any how this car cruised ok but every time he floored it it would lay rubber for about 4-5 seconds and then fall on its face...... he still wouldn't have it ....probly be here in it soon

Ah ... ok , I was under the impression that these pulsing pumps have a set of contacts that open and close to power the electro-magnet that causes the armature ( and thus the diaphragm ) to reciprocate. The energised magnet pulls the armature back against a spring , the contacts open and the spring applies pressure to the diaphragm ( which is responsible for pressurising the fuel ) and the contacts don't close again till the armature has travelled its full stroke . If you block off the outlet there will be no fuel flow and thus the armature will not travel full stroke , contacts wont close , pump stops . I think there must be an internal leak in this pump , most likely in the diaphragm or the valves , obviously this leak is not big enough to lower the efficiency ( yet ) of the pump to the point where it wont pump enough fuel to cause a problem . It may only have a lump of shit holding the valve open ( possibly part of a disintergrating fuel filter ...... got the T shirt ), could try carefully applying a small amount of compressed air to it , in the direction of normal fuel flow . If it were me I would just buy a small rotory pump and fit it ( with the return line ) .... as we all know this thing will shit itself at the worst possible time ..... not nice and close to home.

I guess a closed float valve is a total blockage, and that may happen as the bike idles , or with the ignition switched on but the motor not running
Hamish

Thanks guys for your replies and help on this one.

If I can summarise, I have a fuel pump that pumps fuel OK which then pumps at a lower rate when the outlet hose is restricted, but does not stop. The conclusion seems to be that the fuel pump may or may not be OK.

Options.
I can ignore it and wait until the inevitable happens just as I am on a tricky overtake.
Or I can replace the fuel pump for a vacuum operated fuel pump, taking the vacuum from between the T piece and the Digiplex.
Or take the vacuum from one side of the carburettor before the T piece.

There has also been a suggestion to replace the fuel pump with a rotary one, which I assume is electric. I know nothing about these and would be keen to hear which one would be recommended for the Paso.

There is a further option which is to fit a fuel regulator set to 3 psi which would be a benefit whichever pump was used.

I just need to make a decision as to which is the best pump option, ie leave it alone, vacuum, or rotary. This assumes that the regulator is a given.

Thoughts please, but no more options

Yeah its starting to get like an old ladies tea party . I guess your next move depends a bit on how mechanical you are . Me personally , knowing what I do about paso pumps and having a good mechanical ability ,I would 1st investigate the possibility of pulling it to bits for a look see, 2nd , I would get me a rotory pump for its smooth flow ,from a auto parts store NOT from a ducati shop , and make preperations for a change "on the road", IE terminate the wires on the new pump to suit the existing harness , ditto for the fuel lines and mounting bracket and then make sure I had the pump and the necessary tools ( something to remove fairing screws and hose clips and mounting bracket ) under the seat, and then forget about it ..... and not be to surprized if its still working in 10 years time ...........................I might consider the vacuum pump if it was significantly cheaper , but even if it was it would still be a lot more mucking round to fit .
Shit !! , I wish I was there ..... your probly real pleased Im not
Hamish

I really think you are making the job over complicated. Even if the fuel pump fails it can be by passed with a short length of pipe to get you home. It isn't a good idea to cut off the fuel supply to the pump when it is running, the motor will be overloaded. If you dont want options then you dont want our thoughts.

You probly don't need to be experienced in paso's as such .... its just a motorbike , and maybe you don't even need to be all that experience in motorbikes either, but a bit of common sense would be an advantage , and Im sure your there . If you have followed all this with even a basic mechanical understanding of what is going on ( I mean , Im really sure your an intelligent guy , but so is my Dad , he is a lawyer but if it cant be fixed with paper clips or sticky tape I wouldn't let him near it ) you will come to a good decision as any of the options outlined above ( pulse pump or rotory pump with the return line ,or the vacuum pump ) are good , proven reliable soloutions ..... just comes down to a matter of ( your ) choice. things to do would be to disconnect the battery ( -ve lead 1st ) turn off fuel tap and be ready for some fuel spillage when you disconnect the fuel lines...... have a go
Hamish