Hi, the purpose of starter fluid, which is eyther, is to provide a more volatile substance that lights more easily than gasoline. If a car/bike starts on it, then runs fine, the problem is either bad gas or a weak spark. With bad gas, the problem would repeat when the bike is restarted and it wouldn't really run quite "fine." So this sequence of diagnostic clues leads to a weak spark because even a weak spark will fire a warm engine. Weak spark is caused by coils, igniter, wires or plugs, or sometimes by a bad battery. Carbs are a false lead. If they're bad, they're always bad. The only time symptoms like these might be caused by a fueling issue is if there is a sticking vacuum petcock or, on a FI bike, a bad check valve in the fuel pump or simply a bad pump.
Answers & Comments
Hi, the purpose of starter fluid, which is eyther, is to provide a more volatile substance that lights more easily than gasoline. If a car/bike starts on it, then runs fine, the problem is either bad gas or a weak spark. With bad gas, the problem would repeat when the bike is restarted and it wouldn't really run quite "fine." So this sequence of diagnostic clues leads to a weak spark because even a weak spark will fire a warm engine.
Weak spark is caused by coils, igniter, wires or plugs, or sometimes by a bad battery.
Carbs are a false lead. If they're bad, they're always bad. The only time symptoms like these might be caused by a fueling issue is if there is a sticking vacuum petcock or, on a FI bike, a bad check valve in the fuel pump or simply a bad pump.