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... I thought the coils ran off the signal generator, and the battery just powered lights and accessories.
Signal generator signals the ignition when to fire, that is all it does. If your motorcycle had points and a condenser then it would not have a signal generator, the opening of the breaker points would initiate the spark.

You added LED turn signals, you didn't add more diodes to make the Light Emitting Diodes in those signals light, you added a load to the circuit so that there was limited forward bias voltage to your LED's. That load would be resistors or incandescent lamps not diodes. Diodes only conduct electric current in one direction, LED's are a special kind of diode that emits light when current is flowing in the forward direction.
 

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By the way, it's a Capacitor that makes a spark plug spark. If your engine has points and condenser it is the condenser that makes the spark because the condenser is a capacitor. If your engine has CDI that stands for Capacitor Discharge Ignition and it is still a capacitor that powers the spark coils.

A capacitor is a simple component that acts much like your lithium battery in that it can release or take on a huge amount of power very quickly. The signal generator tells the CDI when to dump the capacitors load into the ignition coils and the coils are just a transformer to increases the voltage from ~12 volts to several thousand volts making a spark at the plug gap, much like lightning. Reduced input voltage to the capacitor will result in reduced spark at the spark plug.
 

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I've been told by numerous people, that if you disconnect the battery, the bike will still run.
Well, you talk to a lot of idiots.
It may run for a little while directly from alternator, but, you will probably burn outt some even more expensive parts.
You are turning ignition OFF and not to PARK?
If it's off and you have any lights on, you still have a serious problem.

By the way, it's a Capacitor that makes a spark plug spark. If your engine has points and condenser it is the condenser that makes the spark because the condenser is a capacitor. If your engine has CDI that stands for Capacitor Discharge Ignition and it is still a capacitor that powers the spark coils.

A capacitor is a simple component that acts much like your lithium battery in that it can release or take on a huge amount of power very quickly. The signal generator tells the CDI when to dump the capacitors load into the ignition coils and the coils are just a transformer to increases the voltage from ~12 volts to several thousand volts making a spark at the plug gap, much like lightning. Reduced input voltage to the capacitor will result in reduced spark at the spark plug.
I've mentioned it many times, you will get reverse EMF from ignition coils 'feeding' capacitor around 300V when engine is running. It tends to stabilise and drop but coil is still getting over 12V after bike starts.
If you look at them in depth, electical systyems tend to be more interesting than people think.
 
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