Technical Uno 1100 Mia Flat spot on pull away

[Mike the Spike]

I have a 2000 model When i pull away the engine hesitates but if i pull choke out a bit when it is warm then the problem gets better. This problem was before the service was carried out and is still there.

 

[Mike the Spike]

The vacuum advance diaphram had a hole in it. Bought a new one and the problem was solved