hi I have just got a 2009 sym gts 125 evo
when you start it up it revs up for about 20 to 30
seconds then cuts out and does this every time you
start it and only ticks over if you keep the throttle
twisted a little bit any ideas would be a great help thanks

Hi and welcome aboard.
When was the bike last serviced.

If it's one with a carburetor you can adjust the tick over but it sounds like the automatic choke has a fault. A dealer could replace it.

Hi and welcome.

hi don't know when it was last serviced
going to do a service on it may be this afternoon
and then take to a dealer to sort out tike over problem