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Yes, I have the A model insert for the Honda Service manual.

What is at issue for me if there are no connections for the change relay is that this circuit tells the CDI to change timing advance value depending on what gear the motorcycle is in. In addition to the safety start lockout while in gear.
 

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My understanding of that system is the side stand retards the ignition and prevents ignition advance and once the stand switch is closed it's in the advanced position for base timing and allows advance to happen. It's not dependent on which gear it's in.
I have not had an A model to experiment with so I'm just using what I read and intrepet from the wiring diagram.
 

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1978 hondamatic cb400a

Hi all

Just wanted to put this up in case any other 400A owners land in the same boat as I did a few weeks back.

Basically, one sunny afternoon after work my 78 hondamatic refused to start. After taking the plug out and seeing no spark, I checked everything I could think of (sidestand, neutral, kill switch etc) but to no avail.

After getting it back home via pickup truck I did some tests on the CDI, the stator, and the coil as per instructions in the manual and found that my CDI was out of limit on a few. If you ever need to find a CDI for a 1978 CB400A let me tell you they are RARE!!!! After calling around everywhere i could, there was a dealership on the other side of Canada that could get one from japan for about 480$. Not wanting to spend that much i looked at ebay for some used ones. I only found 1 and that was 250 shipped.

But after doing some research I found others who had gone the used part route and had dead on arrival parts. I was directed to CDIMAGICIAN and contacted him. He let me know that he does not make new CDIs for the 400A, but his new 400T CDIs will work as long I replace the stator and flywheel with 400T parts.

So back to ebay I went and as most of you know, 400T parts are much easier to get a hold of then 400A parts!! I was able to pick up a stator and flywheel for 200 bucks plus the 100 for the CDI.

Overall I spent 50 dollars more for 1 new part and 2 used, instead of trying my luck on a risky used part (apparently 400A CDIs are known to break down consistently).

The installation was pretty simple, I had to buy a 10 dollar flywheel puller (bolt threaded for the flywheel that you screw in with an impact and it pulls the flywheel off the stator as it tightens). And just follow the manual.

Few notes on the install:

1) the screws holding the Fixed Pulser on the 400A are much shorter than that of the 400T so I had to swap out 2 of the crankcase cover screws to fit on the new 400T pulser.

2) your colour scheme will be slightly different when joining the wires from the new 400T CDI to the old harness from the 400A. It's simple when you look at it, basically you just match up the wires from the CDI to the ones connecting the coil and stator.

3) there are 4 fewer wires on the 400T CDI then there are on the 400A. Meaning you have to sacrifice the kickstand/neutral cutoffs (400A had safety cutoffs that shut down the engine if you put the kickstand down while in gear,. and also wouldn't let you start the bike if it wasn't in neutral). The wires left over from the "circuit board" near the rectifier (light blue and green/black) and the ones coming out of the kickstand switch (green/white and green/black) need to be taped up and tucked away. Same with left over wires coming out of the harness.

Tried out everything and the bike now fires and idles fine. Will be finishing up the taping and taking it out for a test drive soon with new plugs. Will update then!!
Hi,there.I'm having trouble not getting spark on my78 hondamatic cb400a and I saw what you Would advise here on the forum.I'm just wondering what year of the 400t I should get my parts of, like the flywheel and stator?Also the cdi ignition box?
 

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Hi,there.I'm having trouble not getting spark on my78 hondamatic cb400a and I saw what you Would advise here on the forum.I'm just wondering what year of the 400t I should get my parts of, like the flywheel and stator?Also the cdi ignition box?
Any of the rotors and stators for the manual transmission engine from 1978 thru 1986 will work.
1978/79 CB400T 1&2
All CM400 and 450 models
All CB450SC
 

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The side stand switch is nothing more than an off on switch that wont allow the motor to start when the stand is down. It is not tied in to the timing.The timing change between neutral and in gear is controlled by the scr one and two gates in the cdi box. When in neutral at 7.5 degrees the signal flows from the change switch to the change relay thru scr gate one in the cdi box. When put into gear the signal flows from the change switch thru the change relay to the scr gate two and raises the timing to 15 degrees.

I have not had a problem with my cdi box YET but if I do I will take the members advice and switch it out.

This system is very confusing and one of the best wright ups Iv seen was a cb400a winter project thread in the project threads section. Last time I looked at it it was clear back on page twenty.

Bill
 

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CDI ignition modules use capacitors inside. Capacitors have a limited life and even if not used they will age. 30 years is the average useful life span- some more, some less. So, it does not pay to buy used as it is dying anyways. I wonder if some bikes can be converted to points ignition. Less spark voltage, but points has worked for years and is most reliable. I am glad my CM200T is just old enough to have points vs CDI. And, even if a 6 volt system, I upgraded the lights.
 

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Electric starter

When the change switch is in neutral the current flows thru the change relay transistor and the starter will work. when the bike is in gear the current is grounded.




SIDE STAND SWITCH.

When the change switch is in neutral the side stand switch is open and the motor will run with the side stand down. When the bike is in gear moving the side stand down the stand switch is turned on and the current flows thru the SCR1 gate in the cdi unit and the ignition condenser is discharged to ground stopping the motor.


IDLE STABILIZING CIRCUIT


In neutral the change rely transistor is kept on and the SCR2 current is grounded.With the SCR2 off only the 7.5 signal is sent from the fixed pulser to the SCR1 gate. Firing takes place at 7.5 degrees before top dead center. The SCR2 is triggered when the transmission is placed in gear.When this happens both the 7.5 and 15 signals are applied to the SCR1 gate. Firing takes place at 15 degrees BTDC since the 15 degree triggers the SCR1 first.



Changing to a 400 t type ignition system I think you will loose the side stand switch. You can rewire the change switch to have the lights indicate witch gear you in. Probably have to rewire the starter button. You will loose the idle stabilizing circuit and may have to set the idle up a little to compensate for the load when putting the bike in gear. Just some thoughts.

Bill
 

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Any idea if retrofitting a CDI from a 81cb400 hawk would be a similar process?
All the manual trans models used the same parts 1978 thru 1986. Same goes for the A model, same parts all years.
They are not interchangeable between the A and manual trans models, different systems.
 

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I ended up returning the CDI from the 1980 CB, and ended up contacting Ignitech in the Czech Republic. After a brief discussion with one of their techs, I was able to arrange for them to send a programmable ICM, with the '78 CB400A program pre-installed. After about a week from initial contact, I received the new unit and this thing was absolutely well-produced. Extremely well-designed and using quality electrical components. After about 2.5 hours, soldering a few spare wires, rigging this thing up in the place of the original CDI; and boom! my '78 is back on the road again, running better than before honestly!

Only snag is I have a minor oil leak coming from behind the sprocket, but I'll have that fixed by tomorrow most likely (when the new seals come in)! All-in-all if you guys need to replace your CDI these guys are the way to go, trust me! Repairs only cost about $250.00 total (I also replaced the change relay).

Electronic for motorbikes - IgniTech P?elou? - all you gotta do is send them an email and they're super helpful, thanks again to the previous posters who dropped Ignitech's info back in 2011!
 

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I've been running the Ignitech unit since 2013 and 10's of thousands of miles. I was actually the guinea pig for the manaul trans 400's. Now I'm the guinea pig for the 350's, still working out the whole thing while building the engine.
 

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I ended up returning the CDI from the 1980 CB, and ended up contacting Ignitech in the Czech Republic. After a brief discussion with one of their techs, I was able to arrange for them to send a programmable ICM, with the '78 CB400A program pre-installed. After about a week from initial contact, I received the new unit and this thing was absolutely well-produced. Extremely well-designed and using quality electrical components. After about 2.5 hours, soldering a few spare wires, rigging this thing up in the place of the original CDI; and boom! my '78 is back on the road again, running better than before honestly!

Only snag is I have a minor oil leak coming from behind the sprocket, but I'll have that fixed by tomorrow most likely (when the new seals come in)! All-in-all if you guys need to replace your CDI these guys are the way to go, trust me! Repairs only cost about $250.00 total (I also replaced the change relay).

Electronic for motorbikes - IgniTech P?elou? - all you gotta do is send them an email and they're super helpful, thanks again to the previous posters who dropped Ignitech's info back in 2011!
Did the IgniTech CDI work with the change switch and the kickstand switch?
 

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The Ignitech unit replaces the CDI but doesn't have the other circuits for the change switch or kickstand.
The kick stand can be wired into the power circuit so that function remains.
I think the change switch will still work.
 

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Sorry to further drag this post out but I’m in the same boat with my no-spark ‘78 Hondamatic. I understand the CB400T parts are more available but in my search for the stater I’m about striking out for something reasonably priced. How far toward would this work? Could the complete system off a mid ‘80’s CB450SC work? What about even later later bikes that might not have sold in the US? Seems the later the better for availability and life! Thanks, Brad
 

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Sorry to further drag this post out but I’m in the same boat with my no-spark ‘78 Hondamatic. I understand the CB400T parts are more available but in my search for the stater I’m about striking out for something reasonably priced. How far toward would this work? Could the complete system off a mid ‘80’s CB450SC work? What about even later later bikes that might not have sold in the US? Seems the later the better for availability and life! Thanks, Brad
Brad, while you wait for a response to your question, please check your Conversations as below - thanks
303896
 

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SHOWBrad. My self and a couple of other members have been giving this a lot thought. Tests on the 400 A and the 400 T stators show the values are close enough that the 400A stator and the 400 T CDI unit MAY work together. This hasnt been proven yet. My 400 A is still torn down,the plan is to get it up and running then put a 400 T CDI unit on it and see if it will run. .As soon as this happens I will post the results. Other complete systems might work if they fit on the 400 A motor. but I wouldnt spend any money till I knew the system would bolt on. With a non A CDI unit the change switch will tell you what gear your in and the elec starter will work . You can rewire the side stand switch into the kill switch so it will stop the motor when you put it down .The motor will probably fire at 15 DBTDC so the idle will be a little high when the motor is in neutral. Just some thoughts.

Bill
 
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