I have a project I'm working on and I wonder if there are any experts/semi experts out there that could look at a schematic from the 60's and see if it could be improved or updated. It's a vintage motorcycle CDI circuit.
I am going to be putting a few of them together and am curious to know if there is a better way or just go with the current design.

The schematic is here and the red boxed items are external of the CDI unit.

http://www.geocities.com/scullyh2@sbcglobal.net/untitled.JPG

 

Hi,

Not to pass judgement on your design, but I ran a Heathkit CDI on my car in the 60's. It worked fine. Yours appears reasonably robust. I'd stay with it. The one illustrated looks like all the parts are still available, t00. That should be a good reason to stay with it.

It is possible that something much more up-to-date could be designed. It might also be like gilding the lilly - what's the point?

 

Hi there,
Thanks for the reply. I have several of these units that have negative function for some reason or another. Even if they test good on the bench, it's no guarantee they work in the real world.
I was just being inquizitive as to if there were newer better components to use. I was figuring that it would be a moot point, but thought I'd ask.
A side note: The schematic circuit is actually 4 individual boxes/units. They can still be purchased from the manufacturer, but at a rediculous $1550 usd. Approx $400 a unit. ??@#$%#$%??? Figure that one out !!!

I will go ahead with the schematic and thank you for your time and input.

 

Out of curiosity, does 'have negative function' mean they are faulty?

 

Sorry for that, yes negative function = no spark where needed.

 

Hi,

The price is outrageous! Aside from the pickup coils, there's hardly $50 worth of components in that thing.

Frankly, since I got to quit adjusting ignition points, I have no idea how a modern ignition system works. I don't think any are capacitor discharge - but who cares? They work very well. But I'd sure want to look into some kind of replacement for that overpriced CDI system. And let the mfr know about it...

 

Yes the price is beyond outrageous. The motorcycle didn't even cost that much new. The original mfg/designer of the CDI is Mitsubishi.

Question: In place of the (2) 4.7mfd-450v caps, I was going to use a single 2.0mfd 500v cap. Does anyone know if something called a "Pulse Capacitor" would work better in this situation or stick with the std type ??

I've been trying to do some research on capacitors on the internet and ran into pulse capacitors. did some reading, but my knowledge of electronics is limited.