seems to me there is a lot of people suffering fuel problems, common fault misfiring and poor running. we straightaway assume the bike has a problem despite our regular tinkering,makes me wonder if its down to the fuel. As ethanol has been widely discussed over the last few years its dropped back off the radar recently.
a couple of my Brits have problems, the Jap stuff gets used more often and fuel turned over but I see many carbs that have corroded brass parts while overwintering.
as some have problems with fuel evaporating (tufnol spacer discussion) , modern fuel is upto 15% ethanol which absorbs water, this could be vapourising. also I go back to the days of open fuel storage tanks, working in a garage and common to find pinking as droplets of water banging around in the combustion chamber not being burnt off.
would be interesting to use a octane booster additive or maybe try a tankful of Avgas same as we used to use on racetracks until the ACU deemed racers had to use pump fuel.