250 2C

250 2c- the Wee-WeeVees

Re: 250 2C

Postby 72degrees » 17 Oct 2016 17:20

Aha! The 1984ish 2C project I'm working with has a similar device. I *think* it might be a capacitor. Works OK with the two original Ducati Eletroteccnica transducers and a late Red pickup.
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Re: 250 2C

Postby EVguru » 17 Oct 2016 20:27

If you look closely at the device you'll see a diode symbol on it.

It prevents a faulty ignition switch applying battery voltage to the ignition modules and causing them to fail.
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Re: 250 2C

Postby 72degrees » 18 Oct 2016 05:42

I know about the small diode. Is the large can thing in the bottom of the posted photo also a diode?
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Re: 250 2C

Postby Ming » 18 Oct 2016 06:22

EVguru wrote:If you look closely at the device you'll see a diode symbol on it.


Yes, thanks Paul, the diode is visible in the 'chocolate block' and is where it is shown on the wiring diagram. The thing I don't understand is the plastic tube (looks like an electric motor starter) with 2 green, 1 blue and 1 yellow/green wire coming from it. As far as I can see there are no markings on it, it doesn't look 'original' and was attached by a cable tie to a frame tube.
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Re: 250 2C

Postby 72degrees » 18 Oct 2016 07:03

Ming wrote:
EVguru wrote:If you look closely at the device you'll see a diode symbol on it.


Yes, thanks Paul, the diode is visible in the 'chocolate block' and is where it is shown on the wiring diagram. The thing I don't understand is the plastic tube (looks like an electric motor starter) with 2 green, 1 blue and 1 yellow/green wire coming from it. As far as I can see there are no markings on it, it doesn't look 'original' and was attached by a cable tie to a frame tube.


Yet the later 250 l have also has one (whereas my 1980 version doesn't). Did yours come from Spain? Perhaps original equipment for some markets?
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Re: 250 2C

Postby Ming » 18 Oct 2016 08:20

72degrees wrote:
Yet the later 250 l have also has one (whereas my 1980 version doesn't). Did yours come from Spain? Perhaps original equipment for some markets?


Yes, it's a 1984 model, from Spain. The Piaggio transducer is also 'made in Spain'
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Re: 250 2C

Postby EVguru » 18 Oct 2016 15:02

Sorry about the confusion, I'm still recovering from Stafford.

An unmatched pair of ignition units is not an ideal situation.

As for the 'device', I can't be sure. Is the copper plate still present on the ignition winding on the alternator? If not, then perhaps it's an alternative voltage limiter like Soren describes in his videos.

The other thought is that it could be a full wave rectifier. The ignition units only have a half wave rectifier inside and only use every other pole on the rotor. It wouldn't work as intended and give any benefit though as one end of the winding is grounded, so you still in effect have a half wave setup. I've experimented with a full wave setup myself, but lifted the grounded end of the coil, wiring the negative output of the rectifier instead. I didn't do enough testing to determine if there was any advantage.

In any case, I'd remove it and go to a stock setup.
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Re: 250 2C

Postby 72degrees » 18 Oct 2016 15:08

Interesting that my Spanish 1984 model also has one. That has a red pickup and black transducers though. I've left the 'can' in place so far as it seems to start very easily for a bike that obviously stood unused for quite a while.
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Re: 250 2C

Postby Ming » 18 Oct 2016 15:12

EVguru wrote:Sorry about the confusion, I'm still recovering from Stafford.
An unmatched pair of ignition units is not an ideal situation.
As for the 'device', I can't be sure... In any case, I'd remove it and go to a stock setup.


Thanks anyway, Paul. I intend fitting a matched pair of transducers and removing the 'thing', it was just intriguing me, especially considering some of the other 'improvements' that have been made...
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Re: 250 2C

Postby 72degrees » 18 Oct 2016 15:14

Ming wrote:
72degrees wrote:
Yet the later 250 l have also has one (whereas my 1980 version doesn't). Did yours come from Spain? Perhaps original equipment for some markets?


Yes, it's a 1984 model, from Spain. The Piaggio transducer is also 'made in Spain'


They can tolerate weird mid matches of transducer so long as the pickup is the right one but the timing will be out on at least one of the cylinders.

As Evguru says best treat it to a matched pair. Another grey one would work with that pickup I think.
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Re: 250 2C

Postby Ming » 19 Oct 2016 15:34

72degrees wrote:...They can tolerate weird mid matches of transducer so long as the pickup is the right one but the timing will be out on at least one of the cylinders.


Well, whatever the 'thing' is for, I can get a good spark on both plugs. Just need to do a bit more work before trying a 'live' kick.
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