I think one very important issue with modern fuels is that they are designed realistically to run in what I call, "A sealed fuel system" That is, that the fuel tank, the pump, lines, and the injector system are more or less sealed off to the outside air.........This explains why when you remove the fuel cap off your car running on petrol/gas, there is a pressure release. This is a complete contrast to our older bikes and other older machinery, where the fuel system from the tank through to the carb's is an "open fuel system" so it can readily vent to the atmosphere. This causes a major problem, because all the "top end volatility" of the fuel readily dissipates to the outer air surrounding the machine. It is the main reason I advise everyone running these older machines to not use high octane fuel say over 95 or more, because the loss of the fuel properties seams far worse than for lower octane fuels. A higher octane fuel left in the tank for 3 months or more will smell like kerosene, and the engine can be very difficult to start let alone run ok afterward. E 85 fuel is definitely approaching a fuel not dissimilar to Methanol, and it must be used at roughly double the volume ratio to petrol, and as mentioned, it can and will readily absorb moisture from the atmosphere........again this problem is made far worse on our engines with an "Open fuel system".
