Motoscrubs.com

Looking for parts for a 66' 250 scrambler and didn't see a parts for sale/wanted section.

Need an advance unit, AA359, going to a battery setup. Compression release/ valve lifter complete setup, center stand and a gas tank. Anyone have any of these?

[quote= djstedman ...
" didn't see a parts for sale/wanted section. "

____ Have you not ever come-across this page (as a matter-of-course) ? ... index.php ,
where you ought-to have noticed this listing ... viewforum.php?f=5 !?




" going to a battery setup. "

____ Could you please tell us why you wish to make such a change in ign.system type ? _ And how you expect to charge the intended battery ?


Duke-Cheers,
-Bob

I had seen the the classifieds at one point in time, but did not see it this time around, thought maybe it have been removed. What I didn't realize is that you have to be logged in to access this page! I have moved the request to the classifieds.

As for how I approached the battery setup, we covered it a few months ago.. here.

viewtopic.php?f=3&t=1715&hilit=full+wave&start=10

In short I plan to use two power coils that are each ungrounded. 4 wires will exit the primary to be full wave rectified individually then summed at their outputs. There will be a 10W/7V zener diode to prevent the maximum voltage from the charging system going higher than the forward voltage max of the chosen LED.



With this setup I have taken in to consideration the coil, as it is a battery model, but the dwell from the cam on the points is most likely too long in duration. The 28deg advance unit appears to have the shorter dwell cam as it was made for street models (correct me if I'm wrong!)

The other items would be nice, but the 28deg advance unit seems necessary to keep the heat down on the coil and the juice in the battery!

Doug

[quote= djstedman ...
" As for how I approached the battery setup, we covered it a few months ago.. "

____ OH-yeah, I recall that now... I was very-much interested in your intentions with your custom electrical-system, especially because your 4-pole alt.stator was to contain TWO ignition-type power-coils !
The reason I was so interested in it, is because I-myself had always also wanted to try using a pair of the higher impedance power-coils for improved charging of a 12-volt battery-powered electrical-system !
__ However it seemed to me that we really hadn't entirely "covered it" completely back-then, as I recall being rather disappointed that we never got-around to discuss all the related optional circuit-schemes which you could've chosen from.



" I plan to use two power coils that are each ungrounded. "

____ Indeed it's always best to have the power-coils isolated from ground (with each p.coil having it's-own pair of wire-leads), so that ANY power-system configuration can later be chosen to suit (without ever having to go back into the motor-case & flywheel-rotor again !).



" 4 wires will exit the primary to be full wave rectified individually then summed at their outputs. "

____ Your two-pairs of wire-leads from the twin power-coils, with each pair connected to their-own dedicated bridge-block and their full-wave rectified DC.power then combined-together,, ought-to provide over 50-watts, above 3k.RPM.
And if near-around 40-watts of load is-not kept drained-away from the combined power-source's total output, then the system won't be balanced closely enough to go without a regulation-circuit.



" There will be a 10W/7V zener diode to prevent the maximum voltage from the charging system going higher than the forward voltage max of the chosen LED. "

____ It's hard-saying whether a mere 10-watt zener will be sufficient all on it's own to hold-down the voltage-level without becoming overheated,, but with the addition of a battery, those two voltage-limiting items together should be able to cope with any power over-supply from the combined power-sources.



____ Your presented electrical-diagram is quite well-done !
However I'd scrap the fuse for the ign.circuit, and rather add a main-fuse in-line with the ground-wire to the battery's neg.post-terminal.
Also, the ground-symbol still-left shown on the alt.stator/rotor is now somewhat misleading (electrically).
__ Is it your intention to leave the main-lights activated at all times (whenever the key-switch is turned-on) ?
Do you already know what the total wattage-drain is expected to be for your intended load-system ?



" With this setup I have taken in to consideration the coil, as it is a battery model, "

____ With your currently intended circuit-scheme, your n-c.Scrambler's ign.system shall consequently become converted to battery-powered type ! ... But why do you wish to bother with the extra trouble of doing that (when you have the option of still retaining the stock magneto-type ign.system), do you really expect your intended load-system to consume most every drop of power-juice that your custom twin power-coil alternator can provide ?



" but the dwell from the cam on the points is most likely too long in duration. "

____ You're correct that the points-closed dwell-time/duration of your stock 18-degree AAU.cam is way too long for adequately DC.saturating the ign.coil, and-so ought-to be addressed so as to avoid wasted power !



" The 28deg advance unit appears to have the shorter dwell cam as it was made for street models (correct me if I'm wrong!) "

____ You're indeed correct that the street-models employ the particular AAU.cam (with reduced points closed-circuit duration) that's made/intended for battery-powered ign.systems !



" the 28deg advance unit seems necessary to keep the heat down on the coil and the juice in the battery! "

____ You're certainly right to indicate that there's nothing to gain by wasting power-juice just to unnecessarily further heat-up the ign.coil (and reduce the coil's functionality) !
And, not to mention that the 28-degree AAU provides for a more desirable static-timing for rather relaxed kick-starting.

____ Anyhow, I hope you'll have a fair explanation for why you seem to not care to retain the (rather advantageous) stock ET.ignition-system (instead of making your chosen ign.system dependent on a battery).


Duke-Cheers,
-Bob

Bob and Doug,

you know, I'm always interested in DUCATI alternator technology and all those mysteries and riddles around, so I'd like to present here a 3-wire stator, which was left in my cellar by a previous owner. He claimed it to stem from a 125, 175 or 200 n/c model. No DUCATI marking is found on it, only "131267" stamped into the back of baseplate. The 3 mounting holes and the centering dia. perfectly fitted into a n/c left carter.
http://i.minus.com/igu0W1fEgjUAZ.JPG
http://i.minus.com/ibzhhZ5peIOdgE.JPG
I have not already figured out the connection scheme of the coils, nor identified all their winding's starts and ends, but I measured them to float from ground/base plate.
I compared these details to the schematic shown in the referenced thread http://www.motoscrubs.com/forum/viewtopic.php?f=3&t=1715&hilit=full+wave&start=10 and noticed at least one big difference: in the schematic, one of the coils has two layered windings, and their common terminal is tied to ground/base plate.
Can this explain about the ground connection left in Doug's own schematic? Well, if so, a bridge rectifier cannot be used with the corresponding coil, because it does not float.
In the reference thread also some ohmic measurements of the different windings were quoted. These seem partly contradictionary or erroneous to me:
The resistance between "white" and "red" for me must equal to the sum of "white" to GND and "red" to GND - but it's value given is roughly the difference!

Do you have any idea about that?
And Bob, can you identify the stator mentioned above?

cheers Hans

[quote= ducwiz ...
" I'm always interested in DUCATI alternator technology and all those mysteries and riddles around, "

____ That much pleases me Hans, and I wish we had more members with such interest !



" I'd like to present here a 3-wire stator, which
a previous owner.
claimed it to stem from a 125, 175 or 200 n/c model. No DUCATI marking is found on it, "
____ Unfortunately, back in the days when I became a collector of DUCATIs, I avoided keeping the older 4-speed models and-so gained relatively little personal experience to amass much specific information about them, so-thus I don't know very-much about the stock alt.stators produced for the earliest Duke-models. _ However I had come to learn that Ducati didn't produce their-own alternators until some time (near about) after they began producing the 200-models. __ Before that they rather installed alternators produced by 'CEV', so I'd expect that any stator-plate that doesn't have 'DUCATI' embossed on it, would instead boast the CEV logo.
However since you did-not mention seeing 'CEV' shown anywhere on your stator-example, I then can only guess that perhaps Ducati may've copied some examples of the CEV-model and rather installed such copied-versions until Ducati themselves later began designing & producing their-own alternators (for later Duke-models).



" I have not already figured out the connection scheme of the coils, nor identified all their winding's starts and ends, but I measured them to float from ground/base plate. "

____ The term "float" is-not commonly used in std.English that-way, but I figure in this case that it's meant to mean 'non-tangent' and-thus isolated from 'ground'.
__ Anyhow,, since your stator-example's coil-windings are all isolated from ground (thus non-circuited with GND), that makes it consistent with the CEV design (which was made to be used with a full-wave rectifier).



" I compared these details to the schematic shown in the referenced thread
and noticed at least one big difference: in the schematic, one of the coils has two layered windings, and their common terminal is tied to ground/base plate. "

____ While I'm not positive of exactly which schematic you're referring-to, I figure that you're likely in reference to the '28-watt' stator's lighting&charging-coil, which has separate wire-leads -(1-red & 1-white respectively) for each of those two grounded-style coil-circuits.
__ The '28-watt' alt.stator-model was first designed by Ducati for their 160M.Jr-model (and later copied-over to the 1966 & 67 Scrambler-models).



" Can this explain about the ground connection left in Doug's own schematic? "

____ While Doug has not yet responded to my mention of that detail being "misleading", I'm pretty-sure it was just an oversight that he failed to remove after copying the alternator-depiction (taken from another wiring-scheme).



" a bridge rectifier cannot be used with the corresponding coil, because it does not float. "

____ Of-course you're certainly right that a grounded power-coil circuit can-not be full-wave rectified, since such a grounded circuit-pathway can no-longer "float" above & away from common ground.
__ However it's STILL possible to full-wave rectify such a grounded power-coil and still make full-use of the bridge-output, by rather floating the connected load-system, (which is-not so difficult to do, with added return-wiring for fully-floating load-circuits).



" In the reference thread also some ohmic measurements of the different windings were quoted. These seem partly contradictionary or erroneous to me:
The resistance between "white" and "red" for me must equal to the sum of "white" to GND and "red" to GND - but it's value given is roughly the difference!
Do you have any idea about that? "

____ I might but, could you elaborate more specifically in other-words ? _ As I'm not really sure what you're actually meaning to be in reference to by "it's". ...
The red-circuit should be near .5-ohm to GND and the white-circuit should be near .2-ohm to GND,
so-then what are you thinking the resistance-reading should-be (or, is) between the red and the white ?



" can you identify the stator mentioned above? "

____ I'm afraid that if it doesn't state 'DUCATI' or 'CEV' anywhere on it, then I'm not familiar with it's model-type. _ However I most suspect that it's as a CEV design (of which I think Ducati may've employed two different model-versions of).


Dukaddy-DUKEs,
-Bob

DewCatTea-Bob wrote:[quote= ducwiz ...
" Do you have any idea about that? "

____ I might but, could you elaborate more specifically

____ I guess you no-longer need bother doing that now Hans, as I think I've since discovered exactly what had inspired your question...
I found the below pic.diagram which includes the figures which you must've been in reference to. ...


" In the reference thread also some ohmic measurements of the different windings were quoted. These seem partly contradictionary or erroneous to me: "

____ All those ohmic figures given in milli-ohms must've been lab-calculated, cuz I know of no meter able to measure such precise ohmic-figures.
__ While I realize that you're not specifically meaning to refer to the following specific aspect of the questionable-figures, I indeed also find the '.084' & '.243' ohm-figures to be considerably-OFF from where they should be ! ... As they're near only half as high as they ought-to be, (although-however the '.811' ohm-figure [for the ign.power-coil] is quite-near as is expected to be) !
So if those two suspect ohm-figures are-not in error, then it's possible that that lighting-coil was once mistakenly used to power the mag.ignition-system and-so possibly resulted with that power-coil's insulation-coating having become somewhat burnt & weakened (which could've led to [semi short-circuited] leakage between coil-turns and correspondingly resulted with the near-50% reduced ohmic-values).
__ Anyhow,, in regards rather to the "erroneous" aspect of the ohmic-figures which you've found to be questionable, I do indeed have an "idea about that"...
It seems that you've only considered that the grounded-ends of the two coil-windings (on the lighting-coil) were as-if the 'center-tap' is what's commonly-grounded -(as is represented in the related left-side depiction-pic seen lowest-below),, whereas the grounded-ends of the coil-windings connected to the red and white wire-leads, (as can possibly be logically-deduced from the stated figures), must actually be located rather at a physical-END of the entire power-coil (as is represented in the right-side depiction-pic*), rather than at the center-tap location. - (* Please refer to the lower-half of the posted-pic down-below.)
The left-side depiction indicates a ground-circuit at the center-tap, which would result with an ohmic figure-total as you've expected,, however the right-side depiction is what must really be the actual connection arrangement, in order for the questioned/stated ohmic-figures to be actually correct.
After you've looked-over & studied the two differing ground-circuit arrangements, I'm pretty-sure that the likes of yourself will then rather easily comprehend & fully-realize how it's actually possible for all the questioned-figuring to actually properly 'add-up', (according-with the right-side circuit-arrangement ONLY !). _ So then it should now become simply understandable as to exactly why the red to white ohm-figure actually is just ".159" as stated, (instead of '.327' as could otherwise be figured [if the left-side depiction had been actual]).
____ Concerning the construction of the lower-half of the combo-pic... I conveniently made use of an unrelated* pre-existing uncolored drawing of a coil-winding circuit which came to be mostly covered-up by the added-in gray-areas so I could then also add-over the colored wires. - (* So please overlook that the depicted coil-windings are of both left and right-hand loop-turns, [as that's really of no-point with this-topic].)
(Just a rather brief explanation for the somewhat crude-looking drawing.)


Enlightening-Cheers,
DCT-Bob

DewCatTea-Bob wrote:____ Anyhow, I hope you'll have a fair explanation for why you seem to not care to retain the (rather advantageous) stock ET.ignition-system (instead of making your chosen ign.system dependent on a battery).

Well after reviewing all the knowledge on this forum (as I well as I was able to process it anyways), I felt this approach offered the best approach for me. I expect to have 35-45 headlight, as the 25W one I have now isn't sufficient for night driving. The tail light is quite bright as it is a Cree XM-L variant, adding horns and brake lights to the mix I assumed I would go over 50W (just a round number and not just using that number since you stated it in the previous email.

And don't get me wrong I love having a self contained ignition circuits, as they would have a higher probability of getting me home if something were to happen with the battery. So in addition to the Wattage overhead I may or may not had, I did not think living in the city of Los Angeles offered what one would consider a ton of open road, so higher RPMS would not be the norm during traffic conditions.

DewCatTea-Bob wrote:[quote= ducwiz ...
Bob/Ducwiz I quoted both emails in this response to touch on these matters

" Can this explain about the ground connection left in Doug's own schematic? "
____ While Doug has not yet responded to my mention of that detail being "misleading", I'm pretty-sure it was just an oversight that he failed to remove after copying the alternator-depiction (taken from another wiring-scheme).

Yes, this connection is correct, but not necessary, and is misleading due to the lack of detail in the alternator depiction. Both coils are isolated electrically from any ground potential



" In the reference thread also some ohmic measurements of the different windings were quoted. These seem partly contradictionary or erroneous to me: "
____ All those ohmic figures given in milli-ohms must've been lab-calculated, cuz I know of no meter able to measure such precise ohmic-figures.
__ While I realize that you're not specifically meaning to refer to the following specific aspect of the questionable-figures, I indeed also find the '.084' & '.243' ohm-figures to be considerably-OFF from where they should be ! ... As they're near only half as high as they ought-to be, (although-however the '.811' ohm-figure [for the ign.power-coil] is quite-near as is expected to be) !
So if those two suspect ohm-figures are-not in error, then it's possible that that lighting-coil was once mistakenly used to power the mag.ignition-system and-so possibly resulted with that power-coil's insulation-coating having become somewhat burnt & weakened (which could've led to [semi short-circuited] leakage between coil-turns and correspondingly resulted with the near-50% reduced ohmic-values).

These lab numbers were collected using two methods, since the initial measurements were not what I was expecting.

Method 1: Using a milli-ohm meter the three coils were measured individually Yellow-GND, Red-GND, and Wht-GND and the numbers show that the lighting coil was shorting somewhere inside the windings. Where not sure, and really I don't care, as it is obvious that it can't be fixed short of rewinding the coil. As for why the Red-white came out that way, I am not sure, it didn't sound right... maybe if it was isolated from ground it would have been the series sum of the two resistors.
Method 2: Measured using standard lab equipment, this website walks through the details

http://www.robotroom.com/Measuring-Low-Resistances.html

with this method you can get as many figures after the decimal you wish to carry, but may not be significant or actual. With the mill-ohm meter, you can expect to be precise to a milli ohm, and certainly good enough to get hundreths of ohms (.XX ohms). Wish I had the two columns of data to compare, but that is neither here nor there and I would recommend the use of method two for anyone wanting to use a standard digital multimeter, a battery and some radio shack resistors!

Doug

[quote= djstedman ...
" I expect to have 35-45 headlight, "

____ With your intended charging-scheme, that amount of load-wattage (plus that of the intended ign.system's), should be maintainable during engine-revs above 3-grand.
__ I think you can be pretty-sure of having near 40-watts on-tap by 2500-RPM, and I'm reasonably sure that your custom twin power-coil alternator will provide at-least 55-watts by 5-grand, (and possibly as much 80-watts at top-RPM).
__ Certainly compared to Ducati's-own 4-pole twin power-coil alternator (with it's mutual-induction dual-windings [which both each span wound-across both coil-cores]), and it's associated dual half-wave rectification,, your pair of (independently-wound) power-coils, each separately full-wave rectified and combined-together, should definitely provide superior low-RPM power-output ! - (However less available max.power-output [than the Ducati-scheme] at top-RPM.)



" The tail light
is a Cree XM-L variant "

____ Do you know how many watts it consumes ?



" adding horns and brake lights to the mix I assumed I would go over 50W "

____ Actually, those-two loads are of no real concern (on battery-systems),, as they are-not really includible as part of the running load-system, since they mainly draw their consumed power-juice from the battery's power-reserves.
So the only real/significant loads in a std.load-system, are considered to be just the ignition-system & the main-lights, and (to a somewhat lesser degree), the battery as well !



" I love having a self contained ignition circuits, as they would have a higher probability of getting me home if something were to happen with the battery. "

____ Actually, with your intended twin power-coil setup, you should be quite able to produce fair ign.spark for running the engine, even without a battery ! ...
__ I know the engine will fire-up & run at-least with a push-start attempt, whilst powered by just one power-coil,, so-thus your TWIN power-coil setup will no-doubt do same, even by mere kick-starting !
(Of-course this is assuming that the alt.rotor is properly 'timed' with the points-cam.)
__ So I suggest that after you've wired-up your intended electrical-system's charging & ignition schemes, you then go-ahead & confirm that you can kick-start the engine without any battery connected to the system.



" I did not think living in the city of Los Angeles offered what one would consider a ton of open road, so higher RPMS would not be the norm during traffic conditions. "
" I felt this approach offered the best approach for me. "

____ Well I must admit that that's most certainly quite a fair "fair explanation" for preferring to go-with the battery-type of ign.system ! _ Cuz that-way, you'll not squander any power and rather salvage even the few lost energy-pulses which the magneto-type ign.system must inevitably waste to ground !
__ And to that same end,, since the 28-degree points-cam actually has more ign.coil saturation dwell-time than is really needed to create sufficient ign.spark,
you may ought consider (carefully) regrinding your existing 18-degree AAU.cam for an even shorter dwell-time, so that your battery-powered type ign.system wastes less power-juice superfluously saturating the ign.coil !
In other-words, you could quite possibly cut in half the amount of time that current is allowed to pass-through the ign.coil (and-then waste to ground), and yet still produce an equivalently-equal ign.spark, (thus saving still more power [for prevention of battery-discharge during your city-riding]) !
__ Even if you're currently not interested in attempting to modify your stock n-c.Scrambler's overly extreme dwell-valley so that it then becomes the cam-lobe, wouldn't you at-least care to continue discussing the related workings of the modification possibility anyhow, (so as to further realize whether the effort is worth the reward to you) ?


Duke-Cheers,
DCT-Bob