Gilera Nexus 500 Fuel Pump issue ?

[hrccsparky]

Hi All,
I'm having an issue with my 2004 Gilera Nexus 500 and looking for possible causes.
The fuel pump stopped working and upon its removal was confirmed as dead. A replacement was procured and fitted but the engine would not start, then it too stopped working so procured and fitted another one followed by a new pressure regulator and injector to be on the safe side.
Engine now starts and ticks over, but will not rev.
I'm unable to find a new complete fuel pump assembly, so does anyone know of one or what the issue might be if not fuel related.
Thanks.