I had exactly the same problem with my B50.
Would start on rollers but kickstart?--no way.
I had fitted a Pazon and after talking to Andy at Pazon they supplied me with a new "Long Wait" box.
Must admit I have never come across this problem on a twin and I have fitted quite a few Pazons to Triumph and BSA twins.
But I guess a big engine newly rebuilt so quite tight could give a similar problem.
And you are talking of a big bore A65--almost 2 X B50s!