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Evening all,
After my fun with my ignition timing problems I finally took my 350 Strada to have it's Italian `Revisione'. It's like a first time MOT and requires certificates of conformity, wide and varied other documents including a statement that all tax owed has been paid, weird I know. Well, I have run the bike for several hours and checked and double checked all lights, horns and brakes did what they were supposed to. All being good I loaded the van with a very shiny Morini and presented myself to the inspector with my pride and joy on it's centre stand next to me. We did all the horn, lights and indicator checks just on the ignition switch prior to being asked to run the bike and do it all again, no problemo thinks I. The bike started on the second kick and I set about sounding the horn when all around me people were getting very excited, I look to see what was the cause of the excitement when I noticed it was me, smoke was pouring out of the side panels and under the seat of my pride and joy! A hasty shut down and isolation of the fuel duly done I removed the side panel to see all my lighting wiring had melted, spade connector covers too.
Since then I have renewed huge chunks of the fried wiring loom (one of my own creation) checked for earths on all elements including switch gear (also aftermarket) all seems good.
My thoughts turned to a possible charging issue, no snags when on battery, fire raging on generator. I have split the system down to; generator in isolation, reg/rect (aftermarket, not Ducati) disconnected both end and battery (Motobatt MB9U) disconnected and so far have proven; all systems running on battery, with engine running generator puts out 40 ish volts at idle and up to 70 volts with revs applied. From what I have read on this forum that seems about right. I was about to connect the Reg/Rect to check it's output when I got side tracked and decided to check the battery voltage, a good idea it turns out as it was reading 22v between the terminals. I suspect my reg/rect is not all it should be.
On some of the threads people say that a Ducati 748 Reg/Rect is a good replacement can someone please advise me as to the best replacement Reg/Rect for a 350 Strada 1976 with a standard generator?
On a slight side; I was reading the bluebook and it makes reference to a white balance cable between the front and rear transducers. My cct diagrams are a little faded but the link appears to be shown on the early A1 variants but not on the A3, mine I believe is an A2. any suggestions would be greatly appreciated.

As far as the regulator goes, I'm sure there are many suitable ones. Speaking personally, I had a Strada which ran well for many years using a Boyer 'Power Box. Easy to fit, just connect the two yellow leads from the generator to the box inputs, tie back and insulate the red generator lead, then the output of the box to chassis and battery (via fusebox, etc). You can also use it without a battery, though lights will only work with a running engine. I have also used one on a Kanguro and my current 250.
I think you will find that the white leads from the transducers are additional earths.

Yep that's a shame and feel sorry for you.

To add to the good advice from Ming

The generator wires are easily trapped under the stator and shorted, or caught in the casing which I guess was removed to check the cam timing.
There is on many bikes no fusing to protect this fault from causing a fire on 350s with the centre tap regulator.
In a very bad scenario the battery can be discharged through the generator windings causing terminal damage to the generator. Hopefully this is not the case here. Other faults should be fuse protected, assuming its wired up correctly.

I suspect one or both of the thyristors inside the regulator that control the two halves of bridge rectifier have failed and are full on hence the high battery voltage.

As ming says I would upgrade to a modern regulator using the two yellow wires. There are many options available. Mdina stock something which is plug and play, if you want to do some wiring then cheaper alternatives exist. You can also add a fuse (inline) from the battery to the regulator if there isn't one already.



Mark

I have ordered the `powerbox 'and it should be with me in 5 days (Italian customs permitting). I compared several Ducati options and after market versions there-of and decided to go with what you say works.
I removed the rotor again and checked for trapped or burnt wires, I felt sure it was OK as I had an output of 70v at mid-range revs, I really must fix my rev counter, it's on the list of things to do.
I have been doing a controlled discharge of the battery with a single headlight bulb. It has been going for over 20 Hrs and is still at 16v, a bit to go yet I feel.
With the reg/rect out of CCT I tried to start the motor and re-check generator outputs, as luck would have it, it refuses to start so I guess I have dislodged another part of the ignition CCT. Oh well, tomorrows another day and I will try to get back to a decent starting position, i.e. a bike that runs.