'Only runs with choke on' is a symptom of clogged/dirty pilot jets.
You're going to have to pull the carbs, remove the pilot jets and clean them out.
When you get the jets out, hold them up to a light and examine the bores with a magnifier. It should be sharp, shiny and 'machined' looking. If the bores are kind of fuzzy and 'organic' looking, then they're in need of cleaning.
I put the jets into a jar with enough brake cleaner to cover them, soak them for a while, and use a piece of stranded copper wire as a brush for cleaning them.
Strip the wire back an inch or so and you can use a strand or two to poke out the clog when it's softened up by the solvent.
There's a picture in my photo album that shows the location of the pilot jets on Keihin carbs and it's very similar on the Mikunis.
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