450 Jupiter Wiring

[eddd]

Firstly let me introduce myself my name is Mike and this is my first post. Based in south of uk I am currently restoring 450 Scrambler/Jupiter and it goes well. I have hit on a wiring problem, the harness looks all ok but the ignition switch is not isolating the circuit and the electronic ignition in test mode sparks whenever the battery is connected. I have followed the map and can't see a fault but am baffled. Any help from this brill forum much appreciated.
Cheers

[Jordan]

Singles with electronic ignition use a particular switch to stop the sparks.
You probably know that, but just mention it in case - it's different from the switch used for points ignition.
In the OFF position, it kills the engine by grounding a wire from the HT coil unit.
The switch may be faulty, or incorrect type, or it's a wiring connection problem.
If a replacement isn't readily available, you can add a separate kill switch, but you won't have the security of a key. (Ha!)

[eddd]

Thanks Jordan I have the sachse 6v ignition and the standard 3 pole replica switch. Do you know of an electronic ignition switch that I can swap to and is it wired differently than the white, blue and light/earth that goes to the 3 pole. Thanks
Mike

[Jordan]

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[ducwiz]

On the Sachse MHP page, I located this schematic: https://www.elektronik-sachse.de/content/diagrams/ducati_350_points.jpg.
It is more elaborate compared to that depicted here: https://www.elektronik-sachse.de/ZDG3/start/header.php?page=3&ver=3.10&typ=Ducati%20250-450%20Mono&path=DUCATI/250_450/&lang=en. Maybe you did not connect the ign. module's input "7" to the white cable (switched Bat+), but directly to the battery?

Hans

[Jordan]

Hans shows us the Sasche system is not self-powering, but is powered by the battery.
That's not like the original Ducati/Motoplat CDI schemes, so doesn't need the special switch.

[eddd]

Thanks for the replies I just put the points back in whilst the battery is connected the points are live. I earthed the ignition switch to a better earth and the earth wire from the battery and the ignition switch got very hot very quickly. So the problem is same points or electronic. When I test the switch with a meter I get com when closed and nothing when open. Struggling for ideas now and the ignition unit goes to the coil

Thanks for the help
Mike

[eddd]

Having gone through the loom wire by wire with a meter the fault was in the fuse board which had been wired 180 degrees out. Key in switch on spark, switch off no spark. On to the fuel next!!
Thanks
Mike