Just a thought. how exactly do you try and start it when hot?
You mustn't ever use the choke, and if after 3 or 4 good kicks it doesn't start then you wind the throttle fully open and using the decompressor give it ten good kicks to dry the plug. Then you go through the standard procedure again, ie find compression, lift the decompressor and ease it just past top dead centre and then normally with an utterly closed throttle you give it a bloody good kick . Some motors respond better to a tiny bit of throttle but generally jap singles of that vintage shoud be started with no throttle, assuming you've got the idle set about right.
I'm an expert at this I am.
Some years ago when I was a triathlete I went along to see the local ex SAS fitness instructor for some injury or other.
He had me stand against a full length mirror and on looking me over enquired if I'd had polio as a child.
No, just 18 years of kickstarting singles...