I'd like to think I was learned, make an effort to learn stuff, but point out that being learned is a condition that IME is swiftly overtaken by age-induced inability to remember what one has learned. So I may well have mic'ed up the kickstart shafts, must have done since I junked the oilite bush, of a thin-ness that Durex might envy, in favour of a stainless one. But the actual numbers? Forget it. I certainly have.
I'll have a look tomorrow. I think it's 3/4". What I do remember is that my kickstart lever fitted the new shaft in exactly the same way as it had fitted the old factory original, so at least the spline's effective diameter hadn't changed much.
But since |I was following Francois Grosset's advice in fitting the longer shaft, you don't have to live in 221b Baker Street to figure out why the stainless bush has given no trouble.
Why a 1/4" longer shaft is what the factory should have made standard in the first place, giving 1/8" clearance from MY exhaust, need not concern us here.