1966 Scrambler runs!

[bw_nh]

Good afternoon-

My 1966 Ducati scrambler actually fired up this morning- after NO success with the AC ignition from the magneto... I pulled the 6volt battery from my 1966 Mach I, placed it on a step near the Scrambler, hooked up a ground wire from the battery to the engine case, wired the positive to one of my "unknown" coils, and re-wired other side of coil to the points/condenser, and... it fired up!

It pops back through the carb, so I think I may have to play with timing a little.

I still don't know WHY the AC ignition never fired. But now I am thinking, I may just get a small 6 volt gel battery (any suggestions?) and mount that somewhere on the Ducati (It DOES have a little shelf for a battery behind the downtube) and re-wire it so it RUNS. It obviously won't charge the battery unless I get involved with wiring up a regulator of some sort, but... I can always just charge the battery before use.

And/or I can look into an electronic ignition and charging system- Nigel from Lacey Ducati has a system, I believe.

Thoughts on small 6volt batteries?

Sincerely,

Bob Woolner
Hillsboro, New Hampshire USA

A pic from this morning- Rusty is looking on from the deck...

https://live.staticflickr.com/65535/523 ... c8ae_b.jpg

[themoudie]

Keep persevering Bob, a runner is good news. The Electrex systems sold by Nigel have worked for me and solved a 22 month battle, with points, AAU, etc.

As for batteries, I use Mobatt as they are sealed and have no liquid acid in them. They do last longer than Yuasa wet acid batteries on my bikes. BUT they do go PHUTT! Quite suddenly on occasion. I find it best to use an Optimate charger on them, if the bike isn't being ridden and they don't like being left discharged in cold weather, -10°C to -15°C, the Optimate cannot pick them up if they fall below about 11.5v DC charge.

INMHO having the machine rideable and using it, is more important than "BLING"! But's that's just me.

Good health, Bill

[ducwiz]

You need different ignition coils for the AC or DC systems, respectively. If you run an AC ign coil by battery and points it's overheating soon and might die. Vice versa, the DC coil will not produce any spark with the AC alternator power. The original coils were marked with a green or red label. But unfortunately, I forgot which color is assigned to aC or DC, respectively. However, the main difference is the resistance of their primäry windings.

cheers Hans

[Eldert]

the ac ignition system uses another automatic advance unit (AA) to .

the number on that unit is AA 367B . it only advances 18 degrees and has a diff shaped cam for
opening the points to saturate the green ac coil

the dc ignition uses a AA 359 advance unit and that one advances 28 degrees .

Eldert

[bw_nh]

Good morning all-

All interesting! Thanks.

School starts today (I am a classroom teacher, kids will arrive soon), so I will re-read this thread later this evening, and post some replies, and more questions!

Sincerely,

Bob W
Hillsboro, New Hampshire USA

[bw_nh]

Good evening all-
the
My first day with my 7th graders is done-

The ignition coil that is "working" is a " motoplat/barcelona " that I purchased on ebay. I do NOT know if it is an AC coil, or a DC coil. Can anyone tell me what resistance I should find on the windings? This is what I have... I cut this from a VERY old post that I wrote a while ago...

====================================

" To remind you all... I have two different ignition coils that could be used. The coil that was originally on the bike has a green label, with some numbers... 11.06 printed on it. As far as I know, that is the original correct coil. I also have a "motoplat" coil that also has "barcelona" on the top. Same dimensions, but different resistances...

original green label coil... 4 ohms resistance across #1 and #15 . 10k ohms across #1 and center spark.

motoplat coil... 2 ohms resistance across #1 and #15. 6.4k ohms across #1 and center spark.

Which to use? But neither actually seems to produce a good spark... "

==================================
As I mentioned, I am using the motoplat/barcelona coil right now, and it makes a spark, at least enough to run, with a battery ignition. (The battery is a wet-acid SAFA battery that I bought on Ebay a few years ago, that works well in my Mach 1.)

The other coil that I COULD use has a green label... which I think means, it should be for the AC ignition.

Do EITHER of these coils seem to be a better choice for battery DC ignition?

I did NOT know that the ignition advance stuff was different from the AC and the DC ignition systems... I will have to look into that more. But as of now, with a battery supplying 6volts to the coil (and points/condenser) the bike RUNS!. Which is WAY more than it has done in many many years.

I did order a sealed 6volt battery of the proper dimensions, that will fit on that small tray behind the down tube. It occurs to me... that with the bike actually RUNNING... I can test the output of the magneto. Previous to this, i really couldn't figure out how to test that, as kicking it over certainly wouldn't allow me to test AC output.

I probably SHOULD look into the electronic ignition/lights/supply system that Lacey Ducati offers... it would solve a LOT of problems. But... that's a bunch of money/dollars/euros that I would have to spend on an "occasional toy".

Meanwhile, I intend to mount that 6volt battery when it arrives, and try the bike down the road, instead of just running it, propped up on it's stand.

I feel success is in my future!

Sincerely,

Bob Woolner
Hillsboro, New Hampshire USA

[Bevel bob]

You really need the correct AAU unit as Eldert has posted. This will give the coil the correct coil dwell time and give a road bike timing and make it easier to start and also give the big end a much easier time. A blown big end will make the bike worthless.

[bw_nh]

Good evening-

Right. I will check the ignition advance- looking for numbers on it somewhere, which would indicate what I have... and which might tell me what I might need to locate, if I decide to run with a battery ignition.

BUT... the original question still pertains- how do I know which coil to use for battery ignition? Or for AC ignition?

It can not be just the "green label" that makes the difference, it must be the resistance of the windings... what is the resistance readings of the AC ignition coil, and what is the resistance readings of a DC ignition coil? Someone must know...

IF i can locate the battery ignition advance unit, and run the correct battery ignition coil, (I have two to choose from) then I have a running Ducati.

Otherwise, I still need to troubleshoot the AC ignition system using the correct ignition coil... so which ignition coil should I use?

OR... I guess I could purchase an electronic ignition system. But that's an expense I would prefer to avoid. Or maybe I can ask Santa...

And so... still the "Question"-
What are the resistance readings for AC and DC coils? How can you tell them apart? Yes I know a label. Please don't tell me a green label. Does anyone have resistance readings for ignition coils?

Sincerely,

Bob Woolner
Hillsboro, New Hampshire USA

[Jordan]

I don't know about the colours, but if you are happy to stay with a battery system, something like this should be fine to use.
https://www.lowbrowcustoms.com/products ... ucas-style

For an AC system, a coil as used on a points-type flywheel magneto 2 stroke trail bike might be worth trying.

Don't lose sleep over the AAU. The AC type on a battery system won't hurt your engine if the spark is timed correctly, but the DC type might be less likely to kick back when starting.

[tobydmv]

Good evening-

And so... still the "Question"-
What are the resistance readings for AC and DC coils? How can you tell them apart? Yes I know a label. Please don't tell me a green label. Does anyone have resistance readings for ignition coils?

Sincerely,

Bob Woolner
Hillsboro, New Hampshire USA

Hi Bob, I think I have that info somewhere. It might be in the shop manual as well. There is a difference between the two and it is in the windings which are measureable in ohms. I also think the HT coil primary winding resistance should closely match the stator coil resistance.

Since this is a scrambler you want an AC ignition, although that is up to you and may depend on your AAU. Please check your AAU# and report back since it has to match the coil for AC or DC.

AC Coil http://guzzino.com/igco6va.html
DC Coil http://guzzino.com/igco6vodmain.html