When it happened on my XT600e I tried a cardboard shield between the cylinder head and the carb. cutting a square piece (approx 15-20cmX15-20cm) then in half, removing a circle and reattaching around the carb/cylinder connector.
It pushed away/sheilded some of the heat in the cylinder head away from the fuel in the carb and it gave me the definate answer to what my problem was. I'd tried before to cover the inline filter to no aval. All took 5 mins and a quick ride around to see if the bike played up.
Worth a try..?
'Security is a product of one's own imagination, it does not exist in nature as a rule, life is either a daring adventure or nothing.'