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Discussion Starter · #1 ·
We recently purchased a 1980 Honda cm400t. The original owner had been working on getting it to run and he thinks he narrowed it down to a cdi replacement. We bought a used cdi and installed it. When I push the start button, the lights dim a little but nothing else happens. I'm able to jump the stator with a screw driver and I can here the starter turn but I'm still not getting any spark to the plugs. Can anyone offer some insight?
 

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Also you'll want to start with a good strong battery. Maybe your solenoid is bad.
Are the battery and cable contacts clean?
Both plugs grounded when you test for spark?
Your wiring been modified?
 

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I think you meant that you jumped the solenoid? If so and the starter turned and lights dimmed it indicates the following:
 

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1. coil of the solenoid is not open and is drawing current.
2. solenoid is not engaging.

When I brought home my 400A a few weeks back, had the same issue. Gave the solenoid a whack and it freed it up.
You'll need a state of the art Factory Service manual. PM sent.
 

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The start button on these bikes, when at rest, supplies power to the headlight. When pressed it should disconnect the headlight (the lights should go out, not dim) and connect power to the solenoid which then closes connecting the battery to the starter. It sounds like your start button needs cleaning or replacing.

Spark is another issue since the ignition is separate from the rest of the electrical system. The link doode supplied will take you through the steps to diagnose that problem.
 

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Discussion Starter · #7 ·
Update: I replaced the starter relay solenoid and the bike will now attempt to crank the starter. I also bought a new CDI but I'm not getting any spark from the plugs. I'm only getting .5V to the Coil, does anyone know how much voltage you should expect coming to the coils?
 

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Update: I replaced the starter relay solenoid and the bike will now attempt to crank the starter. I also bought a new CDI but I'm not getting any spark from the plugs. I'm only getting .5V to the Coil, does anyone know how much voltage you should expect coming to the coils?
Do the Ignition Diagnosis Doode posted you above, you will narrow it down to the exact problem.
 
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