rich running

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ranton_rambler
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Location: Stafford UK

Re: rich running

Postby ranton_rambler » Sun May 10, 2020 12:29 pm

Possibly teaching my granny to suck eggs, but if you’re using your degree wheel on the timing shaft, have you allowed for it running at half speed?
Ian

Scottish888
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Location: Edinburgh, Scotland UK

Re: rich running

Postby Scottish888 » Sun May 10, 2020 1:30 pm

Hi Ian,

I hadn't considered that, deleted that bad idea, trying to make a shaft adaptor for the other side of the crank.
Regards,
Alex

ducwiz
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Re: rich running

Postby ducwiz » Sun May 10, 2020 4:35 pm

I'd like to remind you of my earlier post http://www.motoscrubs.com/forum/viewtopic.php?f=3&t=3002&start=50#p22635. Studying the schematics, especially the circuits connected to the alternator windings will explain, that the CDI circuit and the Battery/charging circuit are not electrically connected, except chassis ground. Hence, transducers are not specifically made for 6 or 12V. However, they might differ by the electronic components inside, and the no. of turns of the HV coil.
Now, for the pickup: the hint about the internal diode caused me to pull my spare pickup from it's storage box. First, I tried to measure the ohmic resistance of the stator coil, in both directions: infinite / ~ 4.5 MegaOhms!
Then I switched the Multimeter to "diode test": open circuit / 0.75 Volts.
So, there is definitely a diode coonected in series wth the coil winding. Unfortunately, this component prevents the measurement of the coil's resistance so as to have a comparison to a reference value. But at least, it can proof that the diode is still OK. Mostly, a diode fails by loosing continuity, which in turn breaks the trigger pulse's electric path to the transducer. But infrequently, diodes "melt" and so lose their one-way blocking characteristics after a current or voltage overload, and then behave like a resistor.

Hans

ducwiz
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Location: near Frankfurt, Germany

Re: rich running

Postby ducwiz » Sun May 10, 2020 6:54 pm

:idea: More information about adjusting the ignition timing, especially for pickup rotors without marks: :idea:

Ducati_CDI05.jpg

This is an instruction sheet for Ducati service stations, edited by Zweirad Röth, the german importer for Ducati in the 70s and early 80s. It's of course written in german. I tried to translate the essentials:

"Static ignition timing adjustment for the 250 singles equipped with the most recent pointless CDI"

With the aid of a piston stop and a timing whell, find the crankshaft's T.D.C. position as precise as possible. Then, block the crankshaft in the 54° before T.D.C. position (angles for 350 and 450 given below). In this position, the edge (1) located on the rotor must align with the little notch (2) on the stator plate. In case of mismatch, rotate the pickup stator until edge and notch are aligned.


I also dug out from my filing cabinet some works instruction sheets (actual for the 860GT, but also applicable for the singles):

Ducati_CDI01.jpg
Ducati_CDI02.jpg
Ducati_CDI03.jpg

You can extract the necessary information for understanding and adjusting the CDI system.
I did not touch these paers for more than 20 years, had forgotten them unfortunately, because I never had to touch the CDI components in the last 2 decades.

Hans
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Scottish888
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Location: Edinburgh, Scotland UK

Re: rich running

Postby Scottish888 » Sun May 10, 2020 7:56 pm

Thanks Hans,
The 54 deg BTDC for the 250's is what Ventodue said in an earlier post, I see in one of your diagrams that the timing is lined up with the V notch as I was saying earlier.
It seems that 250s with the ducati electronic ignition should be statically timed at 54 deg and using the V notch and mark at the top of the stator.
At least there is now clarity on what the static timing should be and where the timing marks are for 250's like mine
I set the timing to 37 deg so will need to adjust to 54 deg BTDC.
Thanks also for the testing info, will try it out.
It seems that very few bikes out there use the Ducati Electronica system, is that because they failed and owners switched to points, or just less of them sold?
Thank you everyone

Duccout
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Location: Essex UK

Re: rich running

Postby Duccout » Mon May 11, 2020 8:19 am

I can definitely say that a lot of people changed to points from the CDI in the late Seventies and early Eighties when the electronic systems began to break down, as I remember the discussions about it.

Ventodue
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Location: Montpellier, France

Re: rich running

Postby Ventodue » Mon May 11, 2020 8:25 am

Scottish888 wrote:The pickup on the red plastic backplate looks ok, no cracks in the potting, they are just steel plates according to a moto morini site <snip>

Well Alex, as I said before: having had one repaired and taking the opportunity to see inside of it - believe me, they aren't "just steel plates".

Scottish888 wrote: I see a lot of new similar transducer/coils for fantic and other trials bikes around 40 euros but they are for 12 volt I guess

As previously pointed out by Hans: the ignition system and the bikes' electrical system are not related. 6 volt, 12 volt ... irrelevant.
That said, if you must buy a new unit, I'd recommend you get one that is known to work with our bikes, e.g from Ducati Vintage Store. But your call.

Scottish888 wrote:It would be very helpful to be able to test the pick up and transducer functions but I think there is no info out there on this.

You will not find this info, not least because it requires electronic test equipment and understanding that was - and still is is - beyond the capacity of any motorcycle shop or the average Joe Owner.

Replacement is how you test.

Ventodue
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Location: Montpellier, France

Re: rich running

Postby Ventodue » Mon May 11, 2020 8:36 am

ducwiz wrote: Studying the schematics, especially the circuits connected to the alternator windings will explain, that the CDI circuit and the Battery/charging circuit are not electrically connected <snip>

Thank you, Hans ;) .

@ Alex: I won't hammer on any more about this, promise ... :D

ducwiz wrote:Now, for the pickup: the hint about the internal diode caused me to pull my spare pickup from it's storage box <snip>

You're a good man, Hans.

Yes, that is what had 'blown' in my pick-up. It was easily fixed, btw. The most difficult bit was getting the potting resin off ... :o

Ventodue
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Location: Montpellier, France

Re: rich running

Postby Ventodue » Mon May 11, 2020 8:54 am

Duccout wrote:I can definitely say that a lot of people changed to points from the CDI in the late Seventies and early Eighties when the electronic systems began to break down, as I remember the discussions about it.

I think a couple of things got mixed up in the wash, Colin.

1. For many bikers and bike shops at the time, EI was, in whatever form it took, a new-fangled mystery. If one failed, it was deemed irreparable - as, indeed, it pretty much was :) . And replacement parts were hard to find/took a lifetime to get, and cost a fortune. So it was just easier and safer to replace it with something you knew about. And could 'see' working ...

2. The Ducati Eletrotecchnica system didn't have a very long career with the Ducati Meccanica singles, being replaced fairly quickly by a Motoplat system. Which also won itself a reputation for being prone to failure :o . Then, when the Dramah came along, Ducati Meccanica switched over to the Bosch + NGK system. And we all know what happens to the pick-ups on those ... :)

That said the DE CDI system was used - and still is - in a multitude of small mopeds and little bikes. For whom it was designed in the first place, of course.

graeme
Posts: 939
Joined: Sun Mar 25, 2012 12:00 am
Location: Tasmania Australia

Re: rich running

Postby graeme » Mon May 11, 2020 10:35 am

For an electronic ignition system that was made 46 years ago and is still operating in 2 singles I use regularly, it’s not too bad.
And a lot more reliable than the later “boiled in oil” system used on square case twins.

Thank you Hans for the information and well said Ventodue

Graeme


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