1978 Hondamatic 400 A cdi problem

DerekSimpson

My cdi went out on my 1978 hondamatic 400. I have been told that only a cdi from the exact same bike will work. I found one for 150 used. Is there any other alternative. Can you change anything around on a cdi from a 1979 400 a to work. I can get one of those for a lot cheaper. Thanks for any help

fasterspider · Posted: Mon Feb 22, 2010 2:18 pm Post subject:

Welcome to VJMOG
I have never touched a CB400A and do not know for sure what fits and what does not fit in a swap but, here are the part numbers for the ignition modules you are talking about.
78 CB400A
MODULE, IGN CONT
30400-417-014
79 CB400T
MODULE, IGN CONT
30400-413-305
They are two different part numbers.

Bikegeezer

fasterspider · Posted: Mon Feb 22, 2010 8:48 pm Post subject:

I edited my post to show a 79 CB400T part and not the 80 like I posted wrongly before.

DerekSimpson · Posted: Fri Feb 26, 2010 8:50 am Post subject:

Thanks for your help. I ordered a cdi from a salvage yard that is supposed to be in working condition for 150 bucks. It's down at the post office I just have to go get it and put it on my bike. No real hurry though since we are in another blizzard here in pennsylvania. Mad

Need warm weather want to ride!!!!

jvandyke · Posted: Sat Feb 27, 2010 8:53 pm Post subject:

I had an 80 Yamaha SR250 that the CDI went bad on. I too paid big $$ for one from a salvage yard. At the time, a buddy's brother was working as an engineer for Chrysler. He is brilliant. He wanted to see it so I sent it out to Detroit and he returned it "re-designed", "it won't go bad again" he said. I then had two. I don't know what he did to it. I know some of these suffer from heat issues; the solder breaks down. Some will slowly heat them to let the solder reflow and then take steps to keep the box cooler next time. You can try it for fun with your bad one. There are places that will "re-flow" in machines. I sent out a laptop mother board with a bad graphics chip. It worked but still had issues. Cost $50. If it were mine I'd heat it slowly with a hair dryer or heat gun, very carefully and let it cool and try it....for fun.

jeepurz · Posted: Sun Feb 28, 2010 7:28 am Post subject:

im fairly sure ive got one if your deal falls through, ive also got a T if you need info for comparing but im thinkin without looking at a diag the A has 1 extra wire. again im not 100% on that.

DerekSimpson · Posted: Mon Mar 01, 2010 8:50 pm Post subject: still not running

I got the new cdi in the mail and hooked it up today, still nothing. No spark at either plug. I don't understand it ran great before winter even at the begining of december. I rode the bike everyday. Now nothing. Could it be the pulsar at the alternator? The fuses are fine the wires and grounds look ok. I heard that the cdi and the pulsar work together, im just not exactly sure how they work. Anyones help would be great! Thank You

Russell · Posted: Tue Mar 02, 2010 7:58 pm Post subject:

At the risk of offending by asking the obvious.

Is there a there a kill switch and is it turned on or off?Are all the other electrics showing the signs of life that they should?

What made you suspect the CDI in the first place?

Russell · Posted: Wed Mar 03, 2010 12:08 am Post subject:

Derek just found your other thread where you actually answer all the questions I put to you in this CDI thread. Good luck. Like you I tend to think there could be an answer in earth contacts that have been lost during winter storage, given that it all worked so well before.

DerekSimpson · Posted: Wed Mar 03, 2010 7:35 pm Post subject:

Hey Russell no offense taken. It is always best to check the obvious first. I only bought this bike two years ago and did'nt have to do a whole lot other then clean the carbs add a new battery and put on new tires. The bike was actually a show bike. It is made into a cafe racer. I know it isn't anything real rare but it looks pretty sharp since it has been re done. If I can figure out how to up load a picture of it I will. I guess I thought It could have the cdi since the power flow goes from the cdi to the coil. I know now after some research that the alternator triggers a fixed pulsar and that sends the current to the cdi. I will be testing that tommarrow. And the wire to it. I would have known this before If I would have did some more through reading. On the other hand I am glad that I bought another cdi for back up even if I don't use it. They are getting hard to find for my model bike. The other reason I did it was last year my fathers 1981 kz 750 ltd lost spark and i bought a ic ignitor for it and it fired right up. Ic ignitor kinda like a cdi. Anyway thanks and anymore suggestions would be helpful. thanks

05c50 · Posted: Wed Mar 03, 2010 7:50 pm Post subject:

OK Derek, you're starting to confuse me (not hard to do) with your 2 threads about the same problem. I don't know much about the 400a, but looking at the wiring diagram, it looks like one of the inputs to the CDI is from the side stand switch. Maybe check the switch and wiring. Just a thought.
If you think it might have something to do with the kill switch ground, you could run a jumper straight from the battery to the switch.

............Paul

DerekSimpson · Posted: Wed Mar 03, 2010 8:22 pm Post subject:

Sorry about the confusion. I'm new to this site and should have added to my 1 thread but I guess I started a second on the same topic. I'm also not the best on the computer. I was able to figure out how to post a picture of my bike in the album section if anyone wants to vote on it. It's on the last page of the album. I did check the kick stand switch everything seems ok there. Thanks for all your help.

Russell · Posted: Wed Mar 03, 2010 8:24 pm Post subject:

I was musing about Derek's issue yesterday and thought"Did they have ignition cut-outs on the sidestand away back then?"
If they did it certainly is a place to look.I was tricked by one of those on a much later bike, a DR350SE.

jeepurz · Posted: Thu Mar 04, 2010 6:59 pm Post subject:

ditto on the kickstand, going by memory they have a park brake? or something like that, check it too, im curious if its got chopped wiring too, if its cafe'd did they loose the orig loom.