Can i test my GT500 cdi without the special tool?

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Vitoow
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Can i test my GT500 cdi without the special tool?

Post by Vitoow »

Is there a way to test the cdi of a gt500? All resistance values are correct but i'm getting no spark
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markush
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Re: Can i test my GT500 cdi without the special tool?

Post by markush »

Hello...

No, you can't do that without.
You will need some measuring equipment, at least a multimeter.
You also need some understanding of electronics.
See the circuit diagram. With some measurements at the connections of the CDI you can e.g. determine whether the diodes or the capacitor are still intact, etc. ...
You can also apply voltage to the input and see whether the thyristor(SCR) switches when a trigger pulse comes on the line of the "Pulser coil". For that you need appropriate power supplies.
By the way, is your pulser coil OK?
gt500wire.jpg

How do you check whether there is an ignition spark? With this double ignition coil, there is no spark on either plug if only one plug or plug connector is defective. In order to rule out faults in the spark plugs and spark plug caps, do the test with the bare cables against ground.
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rbond
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Re: Can i test my GT500 cdi without the special tool?

Post by rbond »

The only testing you can do is the resistance readings from the stator coils. The CDI gets it power only from the two coils that are stacked on the stator, NO battery power. Also you can check the spark plug coil for the proper resistance. Look at my circuit diagram on making a new CDI box. Parts are about $60.00 at a local electronics parts house or closer to $30.00 from Digikey. I do have 3 spare boards made that work if you don't feel confident in making your own. Check with the 'OZ' board in Australia or google for a chart for the proper resistance values of the stator coils. There is a company in England that makes improved coils at a better price than OEM. Let me know if I can help or how your doing. Robert
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jabcb
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Re: Can i test my GT500 cdi without the special tool?

Post by jabcb »

Rex's Speed Shop in the UK has new aftermarket CDI units.
https://www.rexs-speedshop.com/shop/?s=gt500
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