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Welcome aboard.
The CDI's for the A model are few and far between. There's no aftermarket supplier for them, new ones are extremely rare if there are any, so it's finding a good used one. Another option is switching over to the manual transmission version which requires a stator, rotor and CDI. In that process you loose the side stand safety switch function and the idle compensation timing change. Google CM400A CDI swap plus Hondatwins and a series of topics will come up.
 

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Welcome to the forum.
 

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Discussion Starter · #4 ·
Welcome aboard.
The CDI's for the A model are few and far between. There's no aftermarket supplier for them, new ones are extremely rare if there are any, so it's finding a good used one. Another option is switching over to the manual transmission version which requires a stator, rotor and CDI. In that process you loose the side stand safety switch function and the idle compensation timing change. Google CM400A CDI swap plus Hondatwins and a series of topics will come up.
I don't understand losing the kick stand switch. Everybody is saying that. I'd just wire that into the kill switch with a relay triggered by the neutral switch....
 

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I don't understand losing the kick stand switch. Everybody is saying that. I'd just wire that into the kill switch with a relay triggered by the neutral switch....
Yes, that can be done but no one has done that to date. If you should do that a write up with pictures and wiring diagram would be useful to make a permanent sticky for future questions
 

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Welcome nice bike
 

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Discussion Starter · #7 ·
I finally got around to testing all the parts from the non-running (no spark) bike to the running one. We got all the way to the stator. Both run fine with one and neither spark with the other.
Here's the question: Everything ohms out exactly the same on both, how am I supposed to test them? since they both look bran new, if I had to bet, it's the fixed pulser. Can this be replaced separately? Any other bikes use the same one?
 

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I had the same problem what I did was compare the voltage output, I contented my volt meter to the white wire and to the blue wire coming from the stator and cranked the motor, the voltage from the the bad stator was a fraction of the good stator output. And they both ohmed good. Now for the reason you get this false good reading is leakage in the insulating varnish in the windings, the low voltage of your meter wont see it but when it starts to generate electricity it arcs over and creates a short cut in the windings reducing the voltage output. Your pickup can be tested with your ohm meter, track the wires coming from it connect your meter set to ohms turn your rotor by hand you will see your meter make and brake.
 

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miekk. The side stand switch is wired thru the change switch. The motor will run when the side stand is down and the bike is in neutral. when shifted into gear the the side stand switch is shorted thru the change rely to the cdi box which stops the motor. This was done so you cant start the motor with the side stand and the bike in gear. When you change out the cdi box you will loose this function.

Bill
 

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Discussion Starter · #10 ·
I'm aware of its functionality, I'm stating that that functionality can be duplicated with a simple relay.

miekk. The side stand switch is wired thru the change switch. The motor will run when the side stand is down and the bike is in neutral. when shifted into gear the the side stand switch is shorted thru the change rely to the cdi box which stops the motor. This was done so you cant start the motor with the side stand and the bike in gear. When you change out the cdi box you will loose this function.

Bill
 

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Discussion Starter · #12 ·
Click on home

click on sohc twins

click on electrical discussion

click on cb400 A no spark

Bill
I can't find that exact thread, did you mean the sticky that's actually labeled: 1978 CB400A Hondamatic No Spark Faulty CDI Conversion ?

If so, what are you directing me to read? I can't find anything in there that would indicate the inability to make the engine shut off as soon as the bike was put into gear with the side stand switch activated. Or not let it start while in gear.
Does the bike know when it's in gear or not? Do you lose the gauge gear indicators with the 400t cdi as well? I'll have to look at the actual change switch functionality when I have time.

Either way, my issue turns out to be the stator.
 

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miekk when the side stand is down and the bike is in gear the signal from the side stand switch goes thru the change switch relay and grounds the the power to the coils.

The change switch "tells " the bike its in gear and will short the power to the starter and side stand side stand switch and not allow the the starter to work or the bike to run. Neutral is not wired thru the change switch and will allow the starter to work and the bike to run with the side stand down.
h
Also with the motor in neutral and running when you put the bike in gear the change switch sends a signal to the CDI box to raise the time from 7.5 to 15 degrees to raise the RPM because of the extra load of the auto tranny.

FSM --electric starter inhibitor, ignition inhibitor side stand interlock, idle stabilizing circuit.

Bill
 

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Discussion Starter · #16 ·
With the guys switching to the 400T system on an "A" bike, a circuit would be needed to not allow the engine to run with both the side stand down AND in any gear except neutral.
Is this a functionality people would want back? If not I won't spend any more time on it as I have a spare CDI and 2 spare stators now...
 

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I think some people would like that function, if I had one I'd do it to prevent those "ah, s**t" moments. Memory is good but a distraction while starting can end up with a dumped running bike. Don't ask about the bypassed clutch safety in gear startup.:eek:
 
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