Ducati 250 Mototrans Deluxe?

[ducwiz]

Hi Johnnie,

as Jon Pegler wrote, the conversion into a 12V system is easily done. All you need a single phase 12V regulator-rectifier like this one:
https://www.rexs-speedshop.com/product/universal-single-phase-regulator-rectifier-110w/, and the rest of parts Jon already mentioned. Btw, the "monitor" wire must be connected to the wire on the "gris" terminal, it is + voltage from the ignition switch.
If you are good in electronics I can send a circuit scheme for DIY electronic circuit, and you can modify the original motoplat R-R by yourself.
A modified italian Ducati R-R could look like this:

34.41.06_mod.jpg

Leave the red wire from the alternator unused (insulate the open connector), use onlyy the 2 yellow wires. The R-R is available also from different sources (amazon, ebay, etc.). I have seen it for 10€. You will not do wrong if you buy any of those, but with exactly rhe same wire colours, arranged in the same sequence.
I recommend to exchange the 6V horn too, because it will draw twice the rated current from the 12V battery (i. e. 4 times the power). The corrsponding fuse migh blow. The horn possibly will make a horrible noise, or even not work at all. Such horns are low-priced items everybody can afford.

I have also 2 different parts lists for the 250 Deluxe in pdf format available. I can place a download link here or send it personally for anybody who is interested.

cheer Hans

EDIT: I just found this el. schematic:

23-10-2013 15;24;11 (2).jpg

[Johnnie Mototrans]

Hans / Jon
Thanks for the pointers.
I have had some trouble posting for the last couple of days but thanks to Jim I seem to be back in the game.

[Johnnie Mototrans]

Ok chaps

I am sold on the idea of a 12 volt conversion tho it might not be the first thing on my action plan.
Hans, as you say the single phase regulator rectifier seems to be available quite cheaply and seems pretty fullproof.
But what coil should i be looking for?
I have plenty 12 volt batteries, horns, bulbs and most of the other bits and bobs i am going to need but will need a clear wiring diagram to follow. Are there any other critical components?
Good to know that i dont need the red wire from the alternator. If you check the previous picture you will see that there is not much of it left.

Hans
Yes please can you give me a download link to whatever parts, owners or workshop manuals for a Mototrans 250 Deluxe.

Thanks also to Nigel from Lacey Ducati for your advice on the oil strainer issue.

Johnnie

[Johnnie Mototrans]

20191112_194935.jpg

It looks like the plug thread has been stripped and repaired with an insert in the past.
Possibly a bigger spark plug drilled and tapped to suit.
It seems solid enough at the moment and shows that a previous owner has expended some ingenuity and effort to keep the bike going.

[Johnnie Mototrans]

20191112_194301.jpg

This can't be right. Can it?
The engine case has been cut to allow one screw access to the clutch cable and actuating arm.
It appears someone thought that loosening a footrest, gearlever and a handfull of allen bolts was just too much effort.
I am quite impressed by how well it has been done and might keep it as, apart from water ingress I don't see what harm it might do.

[Johnnie Mototrans]

20191112_194208.jpg

One other thing that has changed since the bike rolled out of a Barcellona factory during the summer of love in 1969.

[ducwiz]

You can download a parts catalog for the Deluxe 5speed in two parts from http://lamaneta.com/web/ducati-classic/, links are in center of the page. The scan quality is not the best, but they are free
The catalog for the old 4speed bikes I have uploaded again (link should live 7 days or 20 downloads this time), quality is stinking bad as well, barely readable: https://send.firefox.com/download/e51367022020b9c4/#WX13V6VJWzErZInlvtIhOw

You can use any 12V coil for battery/point ignition which fits into the coil clamp, i. e. LUCAS 12V type for BSA/Norton/Triumph, Marelli for Moto Guzzi twins, etc. Coils for electronic ignition have a lower primary resistance, thus shoud be avoided.

At the moment, I can't see any other critical component in the conversion process.

EDIT:
for those who are familiar with electronics, here is some information about what's inside this "single phase 12V rectifier-regulator": https://mastercircuits.blogspot.com/2012/07/full-wave-regulator-schematic.html.
The fundamental difference between the original and the replacement R-R:
- the Motoplat is a "series" regulator, i. e. it cuts the connection of the alternator stator winding to the charging circuit, when the. max. battery voltage is exceeded; the alternator idles with a high voltage (60-80 Volt AC)
- the (chinese) replacement is a "shunt" or "parallel" regulator, i. e. makes a short circuit across the stator terminals at max. battery voltage, thus steering the AC current away from the rectifier's input and hence from the charging circuit. The alternator then puts his max. current (but not power) out, mostly into it's own internal ohmic resistance. This is the same load situation as if the max. external number of loads is connected (charging, lights, ignition, etc.)
S, don't be afraid of that "short circuit hazard". It will do no harm to your precious stator copper windings.

cheers Hans

[Johnnie Mototrans]

Thanks Hans
For access to the correct literature for my bike. That should be an enormous leap forward.
Also for your advice on electrics.
I have now ordered the cheap regulator rectifier you highlighted in another post together with what I hope to be a suitable coil and ht lead.
£30 so far seems incredibly modest for a 6v to 12v conversion.
Next test will ge whether or not the bike generates any electricity at all irrespective of voltage.
I have a selection of 12v batteries so all that is left are the 6v bulbs.
The headlight bulb put up a fight tonight and Scotland is currently flippin' freezing so I am inside posting and buying rather than getting on with it.
Cheers
Johnnie

[veloduke]

20191112_194301.jpg


This can't be right. Can it?
The engine case has been cut to allow one screw access to the clutch cable and actuating arm.
It appears someone thought that loosening a footrest, gearlever and a handfull of allen bolts was just too much effort.
I am quite impressed by how well it has been done and might keep it as, apart from water ingress I don't see what harm it might do.
Top

I have a '77 Road that has had a (possibly) '64 Deluxe engine fitted (Engine no. MD 888xx) and some one has modded it in exactly the same way. I would have preferred it was left as original.
I have modded the electrics in the way that has been mentioned, i.e. a single phase RR and use the two yellow wires. Works well.
It should have a DM250 42xxx engine, if any one has one kicking around...

Max

'77 Road 250
'63 TS 125

[Johnnie Mototrans]

Cheers Max.
Interesting to know that I am not alone in having an engine cover modified in that manner.
I can see that it gives rapid access to the clutch arm and the engine end of the cable.
I just don't see why that would be necessary.

Meantime.
My new regulator rectifier is quite literally on a slow boat from China.
I have also ordered up a 12 v coil and lead together with a new oil strainer and drain / fill plugs to replace the well chewed originals.
So that's my Christmas taken care of.

My only other progress has been-
To trace the existing wiring which now has me toying with the idea of remaking most of the loom.
I swapped cables around on the carb and now have a working throttle but it still needs work.
Turn the engine over on a regular basis which I hope keeps the fresh oil circulating and flushing any dirt and debris on the way.