I'm just wondering if it is loading up and it takes a second to clear all the fuel before starting. If it bogs for a bit and then fires, it being rich may explain why you can bump start it but not kick start it. How does it run when it finally starts? Is the jetting clean?
I saw you have a lectron, but I didn't see what needle you have. My motor is an 88mm bore, and I am going down in needle from the 5.2 xl to a 3.2 xl on the advice of Dennis at Packard Racing where I bought the carb. Maybe your needle is too large, and/or set too rich initially. Just a thought, I'm sure some of the more seasoned guys might have some better ideas.