

Not sure what happens to it chemically, but it doesnt evaporate. They sell fuel preservatives that make it last longer. But as a rule, shouldn’t really use multiple years old fuel, unless you have some old bulletproof engine. New engines with their fancy fuel management systems and whatnot will just throw a hissy fit and die.




Even bicycles would be ruined quite fast. Bearings are quite intricate things, you cant really make one on your own very easily. Unless you have some excellent metal making capabilities and accurate lathes. They also need lubrication.
My dad does some bicycling and hes doing small maintenance ever 80-100km or so. Major maintenance once or twice a year. Involves lubrication, cleaning stuff, tightening things, changing parts…