I have noticed the bike stalls when in gear with the clutch engaged I did turn idler screw down a bit but returned it to approx postion when I bought the bike is this seems to have cured it but is this common to the bike.? Another question is it ok to use pre mixed fuel I did about a month ago it is stored in plastic fuel cans I assume it would deterioate in the bike when not in use and I tend to fire the bike up once a week when not in use and let it run for about half an hour and pottering about in the garden on it. Thanks for any replys in avance.

The clutch pack has to be measured to see if it is within specs. If the clutch pull is heavy then you have to check the finger height. https://www.youtube.com/watch?v=hjoj7n74G0s