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Discussion Starter · #1 ·
Hi, I am new to the forum and may have a dumb question. I have a new to me 1980 cx 500. Will this bike run with no battery? I got it running (roughly) using jumper cables hooked to the battery leads, but with no battery. It dies when the jumpers are removed. I know a test for the alternator in older cars was to get it running, and then remove one battery lead to see if it would keep running. Thanks I'm sure I'll have more questions comments soon. Zeph
 

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The older CDI engines technically can run without a battery as it's Stator/Engine rotating that supplies the CDI unit and therefore the ignition.However running without a battery can fry wires and other components as the battery,among other things,smooths the current delivery to the system and soaks up excess current until charged.Also with a weak/faulty battery it can itself cause starting problems.



A CDI engine/Bike has one single CDI box under the seat on top of the mudguard.



The later TAI(Transistor Advanced Ignition) bikes have two,"Spark Units" one for each cylinder near the battery and cannot run without the battery in circuit as,"It" supplies the power for the ignition.



Some CDI Cafe Racer builds do away with the starter motor and fit a small lightweight battery as a substitute/power soak and ,"Bump Start" the bikes.
 

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Discussion Starter · #4 ·
I did a google on the part numbers and answered my own question. Mine does have the TAI ignition. So no battery, no run.........I wonder if there is a diode or something coming from the charging system to block power from coming from anywhere other than the battery.
 

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Welcome to the forum. Please take a few minutes to edit your profile to show your location and to edit your signature to show your bike's year and model.



I did a google on the part numbers and answered my own question. Mine does have the TAI ignition. So no battery, no run.........I wonder if there is a diode or something coming from the charging system to block power from coming from anywhere other than the battery.


No, there is not. But the battery is needed to stabilize the output of the charging system. Without the battery the bike will run poorly, if at all.



Are you certain your CX is a 1980 model? The CX did not get the transistorized ignition until 1982. Or did a previous owner convert it?
 
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