Speedfight 100 hard to start and won't idle

Hi

I bought a speedfight 100 as a project. It was a non runner the previous owner changed the piston and bore but then couldn't get it started.

I have fitted a new carb, and engine seals to the point it'll start 30 percent of the time and revs and runs nicely but if you let go of the throttle it dies and is a big to start again.

I'm tempted to take the bore and piston out to check but as it runs well on the throttle I think it'd be pointless. I have also fitted another CDI in case of the immobilizer but it's all the same. Any ideas welcome

 

Fried piston and rings

 

eletric choke or, i had to convert into a manuel choke because it was giving me problems would just die out, and half time wouldnt start up

 

I'm now having warm start issues. I'm guessing that could be the choke as it's runs starts and rides lovely. So a warm start issue is annoying