I still believe that to avoid the nasty Hydro-Carbon Petroleum fuels, the bikes could be modified to run on the good old renewable METHANOL. True the calorific value is lower than that of petrol so you need more of it to release the same power. Fuel tanks could be bigger or more fuel stops planned.
The best bit is that the bikes could be set up to run on Carstrol R only, yet another naturally grown raw material.
All ok just so long as the farmers don't reduce the output of essential foods such as hops and barley.

Some useful amounts of fuel could be distilled (using solar power, of course) from the natural waste products leaving the bogs of the Bushys Beer Tent, etc.

All that and a green Francis Beart Manx Norton, -------