The voltage figures only tell half the story. A dead battery can give 12v but has no amps which is the important bit for turning the engine (think torque and horsepower difference).
The best check is to put the volt meter on and see how much the voltage drops as you're actually cranking the engine.
My bike currently will start no problem with only about 11.8v showing (I have a volt display fitted), and while cranking drops to about 10v.
If yours is plummeting and not coming back well, it shows the battery no longer has the amps to fire her up.
The best check is to put the volt meter on and see how much the voltage drops as you're actually cranking the engine.
My bike currently will start no problem with only about 11.8v showing (I have a volt display fitted), and while cranking drops to about 10v.
If yours is plummeting and not coming back well, it shows the battery no longer has the amps to fire her up.