my XJ700 ddoes not want to start on cool mornings, (10 -15 degrees Celcius).
I fires and dies. This a new bike to me and don't know the starting procedure.
I've tried the "choke" but it just floods the engine.
It starts fine when the day warms up.
Can anyone help?

My bike has always been like this too, I just chalk it up to the nature of a carburated motorcycle. It usually takes a few tries on really cold mornings for mine to get going.

When it's cold the air is more dense and thus there is more oxygen in it per volume. As such the bike needs a lot of gas to burn efficiently, full choke may just not be enough sometimes <_< . You could turn out the idle jets a bit and see if that helps.

I'm sure there is a more technical explination.