Motoplat electronic ignition

[ducwiz]

Dear w/c owners,

you might know that some of the late w/c singles were equipped with an electronic Capacitor Discharge Ignition (CDI) manufactured by the spanish Motoplat company. It is said to be not reliable, and prone to weakening of the sparks while aging. But, some of you still use it, and it was subject in several earlier posts.
While recently cleaning up my PC's harddrive I discovered some information about this system, that I had luckily stored many years ago, duly before the website holding it finally disappeared. I thought it could be useful for some members to have access to this information. So I compiled a pdf, which also contains the entire electric schematics of a w/c single with the Motoplat CDI and alternator. The link for download is https://www.sendspace.com/file/6w0070.

cheers Hans

[Jordan]

Thank you, Hans.
That is thoughtful of you to re-publish this information.

My Motoplat was bought new and installed to my single. It was fine for a while, but developed the weak spark symptom you mentioned, then failed completely.
A postmortem showed, after removing some of the potting resin, that the CDI charging coil in the stator looked black and burnt.
I think the potting doesn't do anything to help keep it cool.
I converted an non-CDI widecase stator (not potted) with an Indian-made CDI charging coil (scooter part, also not potted) which works well.

[@win]

Now here's a thought.. I've owned 2 '74 350 Mark3s with Motoplat Electronic Ignition. Well, still own 1 of 'm. Both were/are notoriously bad starters. Once fired up, both ran very well.

Due to the starting problems, i had the first one converted back to contact-breaker points. This happened about 42 years ago, so i don't remember if the other Motoplat parts were kept in place. I do vaguely remember talks about problems with the pick-up as a cause of the starting problems.
With the Mk3 i own nowadays i experienced the same starting problems. Instead of going back to points, i chose a different approach and had it converted to a Sachse Electronic Ignition. Motoplat pick-up and Motoplat transducer were replaced. Not a cheap operation. This solution has no use for the alternators blue output anymore. So bypassing any stator problems. Creating other problems tho..

In both cases i never gave the cdi charging coil in the stator a second thought as a source of the starting problems (and neither did any of the experts i consulted). If i'm reading this post well, if the stator had been checked/replaced, there's a good chance i might still be using the other Motoplat components as of today!?

Thanks for posting guys!

Gr. Edwin

[Ventodue]

Hi Hans

Thanks for this. Unfortunately, however, I got the attached 'Password needed' message. May be the fault of my pdf reader, of course ...

[ducwiz]

Craig,

I just checked it, the download works for me. I use the Mozilla Firefox browser.
When you open the link, do you see the reCAPTCHA box, where you must confirm by a mouse click that you are no download robot? If not, you should deactivate your browser's add-ons like NoScript, AdBlock, uBlock Origin, etc., or allow scripting for the sendspace pages.
If that doesn't work either I can send the file per email (which you can pass safely per PN).

EDIT: I just checked again. It isnot a problem with the download. It seems to be a problem with your Nitro pdf reader (which I never used or even know). I prefer the PDF XChange viewer https://www.tracker-software.com/product/downloads/discontinued or the more modern PDF-XChange Editor https://www.tracker-software.com/product/downloads.
Most people use the Adobe Acrobat Reader, which I also checked for working fine.

Hans

[Jordan]

That's right.
It wouldn't open with one PDF reader, but when I tried another, OK.

[Ventodue]

Thanks Hans. I'm sure you're right: it's the pdf reader. (I stopped using Adobe years back when it started clashing with Norton ... )

I'll try another.

Thanks again.

Craig