Kawi2strokes.com Forum

I not sure if anyone can help with a charging problem on my ducati 350 single, 1968. The problem is I have flattened 3 batteries, and I still cannot get it to charge propeper;y. I dont even know if I am over charging or undercharging. Its 6 volt system, and at the last attempt I was runnign 9 volts across when running. I got 5 minutes down the road and it was completely dead. There is magneto on these bikes, so its push it home.

There are only 3 wires from teh alternator, and 4 point on the regulator. I just have got no idea. I can send pics of that helps ? Other wise I will put in on a trailer and spend some money ...I dont really want to , but I cant keep killing batteries either.

Apreciate any help, I know its not triples, but at least I own a triple.

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Steve

I'm don't know Ducatis but I'll throw out what I'd be looking at.

When the bike is running, what happens when you run the bike for a minute or so with a meter attached? Is the charge slowly bleeding off?
I assume your bike uses a small rectifier in the charging circuit. Testing at the output of the rectifier going towards the battery, do you have any significant change in voltage with the bike running vs it being off?
Rectifier any good?
I'm taking flattened batteries means you ran them dead. Are they able to be recharged or are they destroyed?
9v sounds kinda high for a 6v system to have the battery attached. Is the rectifier any good?
Have you chased the wiring between the rectifier and the battery to make sure it's good?
Grounds good? Try testing the ground circuits with a meter from one end to the other. I wouldn't assume they are good just cause they are bolted down. Paint and crap has a tendency to cause resistance if not removed.
Do you have any noticable AC current running from the stator to the rectifier when the bike is running?

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74 H2B with reeds and 34mm carbs
75 S3A Ram Air with reeds and 30mm carbs
73 S2A (wife's bike)
71 Yammi RT1B
83 HD Sportster
03 Yammi R1
06 Kaw 750 Vulcan (wife’s bike)
12 Yammi vstar 250 (wife’s bike)

Ok Regulator, is brand new, the previous one was a 6 volt from honda CB125 and was tested as ok. from an elctricion. I Still have the original ducati one. So I am ruling out the regulator.

The batteries are dead, like I charge them and the hold enough charge to run the bike for a minute and thats it. The wires are good, and there is earth. I tested this by putting the multi meter on the + of the battery and the - on the engine case, and I have about 6.3 volts when battery was good.

I dont know how to test the alternator, so this may be the culprate. It was rewired by an electricion, but he just put new wires from the alternator. Maybe it has lost its charging abilty. How do I test this with a multimeter ? What is the settings I should use on a multimeter. I have aready blown one fuse on my multimeter. .. .. I am pretty dumb at this stuff.

I guess the only other obvious thing is the wiring, but I have the lights working etc, until I go for a ride, and then battery dies. I am not sure if its overcharge or undercharge. I know its hard to describe in words but thanks for trying.

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Steve

350, I remember those systems, but don't remember if they are field excited through brushes, or magnetic only through energy transfer. Sounds like it is field excited, and the field volts go away, turning the charging system off.

There are a couple of things to remember, a generator does not require a rectifier set to make DC volts from AC volts, an alternator does. I think that thing is a generator.

When you get a chance, if you are able to take pics, take some pics of the whole system, lower unit on the crank, and regulator, and e/mail 'em to me, and let me see what it is. Please keep the pics low pixels, e/mail quality, so it doesn't take all day to download them, and send to lymanorman@gmail.com

Is this a scrambler, or a Diana??

1968 scrambler, First of the wide cases. I call it my DuRati. It was pretty bad when I got. I will do in a day or so, hopefully sooner for oics. I have a wiring diagram I download off the web as well. Did I mention there was no actual wiring loom with the bike. Its just been done by me........ maybe the common demonitor here. Appreciate any helo you can give though. I normally just put the pics on photobucket. I will send the link.

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Steve

350, I just found a wiring diagram and manual in jpeg, and tried to attach the web address, but, no dice with it going there, so, here is the wseb address, and I got there by googling 1968 ducati 350 scrambler, and it was the second topic in the list, "1968 - 350cc Ducati Scrambler". www.ducatimeccanica.com/350_scrambler_o ... /index.htm

It has easily accessible wiring diagram. From what I can see, there are three wires from the magneto to the regulator. Two are what appear to be yellow, one red. Inside the mag, there are two coils, of which, it doesn't say if they are in series. or parallel.

From what normal Japanese mag charging systems speak would give, one would be charging for the battery, the other for lighting. I don't think this works like the Japanese systems do.

What I would ask you to do is disconnect the three wires from the regulator, and do ohms tests on those wires.

What I would like to see is the resistance between the two yellow wires by themselves
Between either yellow to red, then, red and yellow, one at a time, to ground

Post what you find, please.

Now, common sense would tell me that a permanent magnet magneto would have either one or more magnets inside the rotor, and that those magnet(s) would have both a north and south end for each, and that would indicate the charge was alternating current. This would mean there would have to be either a rectifier inside the regulator, or, they only discriminate one phase of charge, like taking only the positive charge wave.

After you get the resistances read and recorded, charge the battery so the engine can run. Leave the wires from the mag disconnected, START the engine and let it idle, and test for output voltage between the red to ground, yellow to yellow, yellow each to both ground and red. Also, do the above running voltage tests in both AC and DC checks. Then, if possible, redo the tests at 2,000 rpms or so. This should confirm/deny charging out of the mag at the different outputs between idle and rev's, and whether it is AC, or DC.

Post findings, please.

The ignition system appears to be a battery/points system, but has one wire from the regulator to the positive side of the ignition coil, for what reason, I have no clue.

BTW, the magneto is behind the primary gear, between the case and gear, so, left case, clutch and primary gear are all remove items. That site has jpeg's of the tools and how to, for all operations, so, have fun with it. .

Ok . My 3rd battery is dead, and I cant stomach another killing. I cant get he bike to run to do the tests on the fried battery....... I have bitten the bullet and taken it to my mechanic... semi retired to see what he can do. I appreciate the advise, even about the brown wire to the coil. Apprently this is normal for ducati. Apparentlyt it has magnets as well. My Mechanic told me another customer bought a 12 volt system from germany, complete with CDI, high tension leads, altanoter, +++ for 500 bucks. He said its great quality. I may bite the bullet and go down this path yet. I have not ridden the Ducati more than 3 hours in 10 years. I am very much over Ducatis and when it was going, well very similar to a Honda 250 , except with vibration. Very much a crap bike to ride. Shame they look so good.

Any one want to buy a Ducati 350 scr ?

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Steve

I have a 450 Diana, and I haven't had issues with the electrics...yet. Just lucky.

Knowing the system has a magneto as well as battery power to the coil says there is a problem with the lower charge unit, one or both of the coils. One would have to think that the battery power was there to help with starting, and running would be off the magneto, so, if it doesn't stay running, there would be a problem with the magneto coil/s.

But, then, it all depends on if there is a switching device inside the stock regulator to switch from battery start, to excited magneto for the ignition.

Sounds like you made the right decision, person closer to you that has practical experience with that system, good deal.

Strange how things work out, Apparently the alternator has come completely away from its plate. Strange. The good news is one of the magazine liked the look of it so much they have taken some photos. I am yet to to find out details, pity its not my kawa which almost ready to be registered. Just a speedo cable and MC to go.

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Steve

Do I understand correctly this is a 6 V battery ?
And, are you charging these batteries on the bench first ?
If so, what are you using to charge them with ?

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Busy doing more riding than wrenching.......