<press starter button>
engine starts
<release starter button>
engine stops
engine only continues while the starter button is depressed (no not psychologically)
any attempt to use throttle - engine stops

Am thinking this is a 'fing' in the right hand switch block ?? but where to start and what to look for? a gremlin?

What bike?

oops sorry FF - Aprilia Pegaso cube

Has she sat for a while with the same fuel?

Andy suspects dodgy fuel/carburation possibly in conjunction with low battery giving less spark. - so fresh fuel and recharge battery and then easy start/ carb cleaner - lots of... down through the venturies - fuel off - run her on the easystart and slowly slowly bring the fuel in and gently increase the throttle. THis happened before and the above fixed her - He thinks the starter motor is a red herring (possibly pressing the button giving stronger pulse to spark and/or retarding the ingition to stop her back firing and eating the starter gear on start up?)

xx

....

Sorry I cant help, I am to electrics what Jack the Ripper was to the Royal Colledge of Surgeons

Ah. Might have been able to help with a Jap bike but I don't have any wiring diagrams or experience with Italian stuff.

Normally the starter circuit is protected by one or more relays and safety switches for clutch, stand or whatever but if they're in a position where it'll start (as yours) there's no reason for it to cut out once you de-energise the starter solenoid by releasing the button.

@biker835 nod nod me too
FF thanks for trying

Sheb - nod nod - thank you , Andy did tell me but I didn't have a note book to write it all down.
Unfortunately I can't do anything in the rain, there's little room and none of the tents will go over her (and me) so she'll have to sit there some more, was hoping to bring a small thing indoors and fiddle - could have managed that, but emptying fuel and removing battery isn't a kitchen chair job