rich running

[ducwiz]

Your ignition system is a Ducati Elettronic CDI. The electric power for this device is generated by a seperate, single winding on the alternator stator and routed to the CDI transducer via the green and white wires coming from the crankcase/stator. This winding has no connection to any other electric circuit on the bike, except chassis ground. This means: it works totally independant from the DC charging/lighting circuit, which is powered by the 2 yellow and 1 red wire. In turn, the voltage of your battery, be it 6 or 12V, has no influence on the spark generation.
See this circuit schematics (italian version, sorry):

Screenshot - 25_05.png

Screenshot - 25_05 002.png

This system works similar to an old brit bike with a LUCAS magneto - you do not need an alternator or dynamo to run the engine, but to stop the engine you need a cutout contact on the ignition switch to short the pickup signal to ground.

As you said, your strobe light is designed for 12V operation, and so you connected it to a 12 V battery - well done. Possibly, the strobe's internal electronic circuit needs a ground connection, so I would recommend to connect the 12V battery's minus-pole with the bikes chassis. The plus-pole must be left open. This might stabilize the picking-up action of the sparks, in turn enabling a check for the automatic advance action.
When you in fact made this test, please report the result, then we can continue problem-solving.
Btw, there have never been ignition reference marks behind the hex plug in the clutch cover, but on the covers's outside, above the hex plug. This is possibly a misinformation in the Haynes manual. To check the ignition timing precisely, you need a special pointer, which can be attached to the crankshaft and rotates with it. The procedure is depicted and described in the user's manual.
On some bikes, timing marks can be found on the ignition pickup rotor/stator, located under the chromed little cover on the rh side. They are useful for a first static timing adjustment, see Haynes manual.

cheers Hans

[George]

Have thought more about your problem and for me most likely cause is ignition advance or rather lack of. Indicated by loss of power as revs increase. In other words at higher revs ignition is to far retarded. if it was my bike I would check advance before trying anything else.

[Scottish888]

I apologise for the length of this thread, at least it could serve as a total troubleshooter when/if I get it fixed.
I would also like to thank everyone for their good advice, it really is much very appreciated, without this forum and your contributions my bike and many others would still be wrecks.
When riding it today, it almost felt like a switch, 5000 rpm, open it up and just occasional firing, close the throttle and it comes to life at 5000 or less.
it seems about the right revs for a change up in advance but could just a non advancing ign cause nothing, I thought it would still run but with reduced power? Maybe I'll drill a hole in the casing hook the ign backplate onto a wire and yank it to full advance caveman style while riding its making me that mad.
I could try setting it to full advance and if it will start then try that but I doubt it will start.
Hans, I will try to get the strobe working by your method, it should pick up the spark pulse then.
Is it possible that there are advance markings on the ign stator and rotor? There are certainly a couple of casting marks, one is the dot for static timing the other a channel with a notch at the edge looks like it is for timing.
You can see the groove marks at the top of the stator, looks like that could be used for advance timing? someone has put a white mark on the backplate before.I made a black ink mark just beside the raised part
Photo is at TDC
The other is the coils at assembly..looks ok but I never tested

d ign.jpg

duc ign coil.jpg

[Jon Pegler]

At a guess you are well retarded.
The dot on the rotating magnet is obviously in the correct place as it cannot change, but the mark on the fixed part seems to be a homemade mark and a bit retarded.
There is usually a small notch on the backplate that line up with the dot on the magnet at the full advance position.
This is at approximately the three o'clock position, not the four o'clock position in your photo.
Put a degree disc on your crank and set the position to 28- 30 degrees BTDC.
The dots should line up.
This will give you a starting point with which to strobe time the motor.

Jon

[Scottish888]

thanks Jon,
On that photo, it is exactly TDC, I had to make that mark on the backplate as there was no other mark anywhere.
I had asked this question a long time ago when I was setting it up, I even got a magnifying glass out, for sure there is no indentation or scribe or any type of mark to go on, I double checked today. on the photo I took today I can zoom in quite a bit...no marks.
I thought with the retaining screws being near central in the slots, piston at TDC then I would just put a mark there to start with.
If the mark should be at 3 then it is well retarded, Could anyone post a pic of a properly timed Eletronica system so I can see where the timing mark is at TDC?
I can try setting it at 3 o clock. I was adjusting it whilst runing it today, full range of the slot, it certainly seemed best around that central slot position but that was only about 2000 rpm and not accurate as a bit risky.
The upper marks raised part forming a V notch, I think this is the timing mark for 30 deg before TDC where the white mark is on the backplate.
That is 30 deg before the TDC in the pic. Maybe the factory had different marks towards the end of production?
I have a rather large timing wheel for a car, I'll need to make some distance piece and find a screw to fit.
Hans, There are no marks for timing anywhere on the clutch case near the hex plug.
Thanks again

[graeme]

Clutch cover
See dot and dash

7A496A3E-D090-4ABF-9F88-CA5F91153481.jpeg

Graeme

[Ventodue]

<snip> Could anyone post a pic of a properly timed Eletronica system so I can see where the timing mark is at TDC?

Will try to get it done later today - 450 SCR, btw.

Later ....

[Scottish888]

Thanks folks

No marks on the clutch cover of my bike, timing marks at stator backplate not present..what happened with this machine.
Found this info about the ducat eletronica system advance.

"The 450 pick-up rotor uses the amount of pole that overlaps with the stator pick-up pole. There is no defined point of maximum magnetic flux flow. It depends on how much of the rotor pole is overlapping the pick-up, that is flowing magnetic flux, and how fast the lines of force are being cut (speed of rotation). At low speed it needs more of the rotor pole passing magnetic flux to generate a voltage. As the speed of rotation increases, because of the speed of flux change, less of the pole needs to be overlapped, to generate the voltage. So the spark is advanced gradually as the speed increases.
You can see that there is no defined point of triggering, just two long sections of poles on the rotor, that pass the magnetic flux across to the stator."

The Haynes manual refers to an air gap between pickup rotor/stator air gap but fails to say if it can be adjusted, can it?

duc clutch cov.jpg

[Duccout]

George has a point - could the valve timing be out? Might be worth doing a quick visual test by putting the piston at tdc on the compression stroke, pulling off the cam end cap and checking that the cam lobes are at 4 o'clock and 8 o'clock.

[graeme]

Looks like your clutch cover has had the marks polished off at some time. I’ve seen that before.
Best find TDC using a piston stop to be accurate.
Mark your ignition rotor and adjust the stator (red) so it starts and idles, then strobe to be sure it advances.
If I give you a picture it will be of a 450, so not much use to you for a 250.
My 450 advances to full advance at a bit over 3500 revs (28 degrees) and doesn’t change with more revs.
I don’t know if the same ignition is different for the 250 ?
There isn’t much information on these.
What you last posted is the best description of how it works.
I use NGK BP7HS and a resistor plug cap.
The spark is piss poor but it rides well.

Graeme