I have a Morini 500 I have been restoring(I have posted updates here in the past with pics)--well I finally got the bike running

First time it has ran in 23 years--to get the intial start we had to bump-start it--pretty funny towing a vintage motorcycle behind a pick-up on the streets of Pittsburgh, but I digress. The bike ran, and would restart that day(both with the electric start and the kickstart)--anyways, after sitting overnight, it would not start again--as if the carbs have lost their prime--we got it bump started again--but I am lost as to why it wouldn't fire again after sitting overnight. The carbs are Delorto PHBH venturi-types which I rebuilt. Just wondering if anyone has had a similar experience with their bikes and what exactly I should be looking at. Final pics of the re-assembled bike will be posted next week.