Wiring-I'm Confused

[Ducatikid]

Calling on all the great and powerful "Electical Wizards".........With a 160 Monza Jr, I'm trying to get my newly rebuilt engine to spark my plug. I have a 3 lead harness (yellow/red/green) My schematic shows that all I need to do is connect the yellow lead,plus the lead from the point/condenser to one side of the coil and ground the the other side of the coil. If everything is functioning as it should I will get a spark at the plug...right? (turning the engine over of course). The other 2 leads of the stator are used for the battery/lighting system....correct? I ,also, assume that since the stator,points,condenser,spark plug are brand new my only questionable part in this arrangement would be the old ignition coil? BTW, the plug wire is ok, but, if I need a new 6V coil where's my best chance location to get one? Any 6V ignition coil will work won't it? SOooo, I need some advise and instructions, please and thank you. Tom

[DewCatTea-Bob]

[quote= Ducatikid ...
" My schematic shows that all I need to do is connect the yellow lead,plus the lead from the point/condenser to one side of the coil and ground the the other side of the coil. If everything is functioning as it should I will get a spark at the plug...right? "

____ Yes, that's indeed correct !



" The other 2 leads of the stator are used for the battery/lighting system....correct? "

____ Yes, however those are two separate systems, as the main-lights system is ran with raw-AC alt.power, while the battery is to receive rectified-power (that's merely sufficient to keep it charged).



" my only questionable part in this arrangement would be the old ignition coil? "

____ Unless it's been obviously damaged, it ought-to still be functional.



" Any 6V ignition coil will work won't it? "

____ Most any ign.coil should provide a spark, and it need-not necessarily be rated as "6v", (as the power-source is-not really set as '6-volts' !)



" I need some advise and instructions,"

____ The stock alt.cable should have a White wire-lead for the rect.diode,
a Red wire-lead for the main-lights,
and a Yellow wire-lead for the ign.coil (points-side) !
__ Do you have an ohm-meter ?


Hopeful-Cheers,
-Bob

[JimF]

I know Bob has not finished weighing in on this.

Seemingly your alternator wires have been changed out and that is typical as age and UV rays over time degrade the insulation on the wires.

If someone before you changed out the wires they did you a favor because it's not exactly easy to do although they did not match the original colors. Forgive them for this oversight. Finding three wires of the correct colors in the desired wire gauge with an oil, fuel and UV resistant outer sheath of a diameter suitable to pass snugly through the grommet on the engine case would be no easy task, so the easier repair is to utilize an old computer AC line cord. Usually the wire gauge of a computer line cord is suitable as is its outer diameter, and nowadays most line cord sheaths are UV and oil/fuel resistant.

However the internal wire colors will not match the original Ducati colors and perhaps that is what has happened to you.

I am not familiar with the 160. but on the 250s there are two internal coils. I believe that the 160 is the same.

Each coil has two ends, so to electrically connect to each end of the coil would take four wires.

You have only three wires coming out of the engine grommet which are connected to three of the four ends of the two coils and this is because the fourth "wire" is internally connected to the motorcycle frame. So the entire frame becomes the 'fourth' wire.

To learn your new wire colors will take an ohmmeter. Two of the wire ends will measure zero ohms (shorted together) end-to-end. Those two wires should measure infinite ohms (open circuit) to the motorcycle's frame. Those two wires are connected to opposite ends of one coil.

The last wire should then measure infinite ohms (open circuit) to either of the other two wires, and it should measure zero ohms to the frame. This last wire and the frame represent the two ends of the other coil.

If you would check these wires so as to identify which two colors are connected to each other through one coil and what color wire is connected through a coil to the frame, it may help Bob tell you which wires to use as he continues to assist you with getting your bike to work.

Jim

[DewCatTea-Bob]

I know Bob has not finished weighing in on this.

Seemingly your alternator wires have been changed out and that is typical as age and UV rays over time degrade the insulation on the wires.

If someone before you changed out the wires they did you a favor because it's not exactly easy to do although they did not match the original colors. Forgive them for this oversight. Finding three wires of the correct colors in the desired wire gauge with an oil, fuel and UV resistant outer sheath of a diameter suitable to pass snugly through the grommet on the engine case would be no easy task, so the easier repair is to utilize an old computer AC line cord. Usually the wire gauge of a computer line cord is suitable as is its outer diameter, and nowadays most line cord sheaths are UV and oil/fuel resistant.

However the internal wire colors will not match the original Ducati colors and perhaps that is what has happened to you.

I am not familiar with the 160. but on the 250s there are two internal coils. I believe that the 160 is the same.

Each coil has two ends, so to electrically connect to each end of the coil would take four wires.

You have only three wires coming out of the engine grommet which are connected to three of the four ends of the two coils and this is because the fourth "wire" is internally connected to the motorcycle frame. So the entire frame becomes the 'fourth' wire.

To learn your new wire colors will take an ohmmeter. Two of the wire ends will measure zero ohms (shorted together) end-to-end. Those two wires should measure infinite ohms (open circuit) to the motorcycle's frame. Those two wires are connected to opposite ends of one coil.

The last wire should then measure infinite ohms (open circuit) to either of the other two wires, and it should measure zero ohms to the frame. This last wire and the frame represent the two ends of the other coil.

If you would check these wires so as to identify which two colors are connected to each other through one coil and what color wire is connected through a coil to the frame, it may help Bob tell you which wires to use as he continues to assist you with getting your bike to work.

Jim

____ Jim is at-least correct in that my initial response-post was a rather hasty-one, (which was what it was because I'm too wound-up cuz someone broke-into my house this-morning, so I'm really not up-to concentrating my thoughts on anything here today).
____ Anyhow, everything-else that Jim has stated is also pretty-much quite true, PROVIDING that we were in regards-to a '40-watt'/older-version of the alternator employed on the nonbattery-powered 250 n-c.models ! _ But-however in THIS case of a 160-model, IT's alt.model is the '28-watt' version,, which is considerably DIFFERENT ! ...
THIS alt.model has three separate circuits (from it's two completely-separate power-coils)...
ONE circuit-lead (colored yellow), is from it's-own dedicated power-coil (to the ign.coil),
and the other two are both from the second power-coil... ALL three power-coil circuits have their opposite-ends internally-grounded to the alt.stator-plate ! - (With the Red & White circuits sharing a center-tap arrangement.)
__ I've never seen ANY three-lead power-cord/cable with a YELLOW-wire combined with a red-wire and a green-wire, so I'd suspect that YOUR alt.cable was put-together by someone who didn't happen to have a sufficient length of white-wire.
And anyone who had the ability to replace the original-stock alt.cable, ought-to have been at-least smart enough to have matched-up the yellow with yellow and the red with red, thus leaving the odd-colored wire to be assumed as the white-wire's replacement.
How-about posting a picture of your alt.cable, showing it's three wire-leads ?
__ To double-check which wires are which, (Jim's deduction-reasoning won't work in this-case because ALL three lead-circuits will circuit to ground !),, you'll need to measure all their individual resistance-values, (with respect to ground).
Pretty-much all-of the related details have already been covered (in at-least one-other thread), back before 2011. - (Try searching fellow-member: captpaul 's posts from back-then, to possibly more-easily locate a related-thread.)
Here are a couple related threads which you may find of interest...
viewtopic.php?f=3&t=61&p=310&hilit=28+watt#p310
viewtopic.php?f=3&t=66&p=369&hilit=28+watt#p369


Duke-Cheers,
-Bob

[Ducatikid]

DewCatTea-Bob & JimF, Thank you gentlemen for your answers. My main Multi-tester is toast, so all I have is a simple test meter from my old telephone repair days . Believe me the 3 wires coming out of the engine case is yellow/red/blue! I tested all leads and there is continuity between them all and to ground. My HT coil posts have continuity to ground ,but, not to each other. I reworked my HT coil lead to the plug...it's ok now. I have everything connected as I have described in my OP and still no spark. That was my reason for asking about the HT coil.....I was thinking it was my problem. BTW, I put my tester on the wire to the points/condenser and could see the points open and close. The builder replaced everything new on his rebuild to this engine. I wouldn't think the stator/mag would be bad or the point/condenser. Am I missing something???? Thanks again Guys......Tom

[DewCatTea-Bob]

[quote= Ducatikid ...
" all I have is a simple test meter "

____ So long as it can measure ohm-readings under 1-ohm, it will do.



" Believe me the 3 wires coming out of the engine case is yellow/red/blue! "

____ I requested a picture not because you-yourself were doubted, (although it NOW seems that that may've been a fair consideration since one alt.wire-lead has changed from "green" to "blue"), but rather because I wanted to see if the alt.cable-conduit (in most particular) appears to-be as original or not.



" I tested all leads and there is continuity between them all and to ground. "

____ As indeed there should be, since the 28-watt alternator-model allows all it's circuits to pass-through ground, (thus allowing inter-continuity through to all).
So-therefore more-so than mere 'continuity', we need ohm-reading values in order to be SURE of exactly which wire is which.



" My HT coil posts have continuity to ground ,but, not to each other. "

____ That should-not be the case, (unless of-course you neglected to first make-sure that it's contact-points were set into their open-position, and also failed to disconnect it's ign.coil's ground-wire, before performing your test).
But assuming that you had the HT.coil removed, THEN neither if it's connection/terminal-posts should have ANY continuity to it's (normally grounded) metal body-casing what-so-ever ! _ HOWEVER, the HT.coil's pair of posts SHOULD indeed actually have continuity to each-other !
So if you're totally-sure of that which you've stated above, then your ign.coil must be BAD !



" I have everything connected as I have described in my OP and still no spark. That was my reason for asking about the HT coil.....I was thinking it was my problem. "

____ It's now seeming to me as-well that your HT.coil may indeed be the actual source of your lack of ign.spark. _ So double-check all your continuity-testing with it completely disconnected from everything (except your tester of-course).
__ Can you post a pic of your ign.coil ? _ As I'm doubting that it's the stock green-labeled HT.coil-model.



" I put my tester on the wire to the points/condenser and could see the points open and close. "

____ By: "see", I assume you really meant 'electrically' on your test-device, rather than actually physically-viewed.
__ That was a good test to try, as many who install the ign.contact-points fail to make-sure that they're properly isolated from ground, (thus-then possibly making ign.spark impossible).



" The builder replaced everything new on his rebuild to this engine. I wouldn't think the stator/mag would be bad "

____ I also doubt that your alternator-itself has gone-bad, however it's quite possible that the builder him-self had no-idea that it's mag.rotor needed to-be particularly installed with it 'timed' in relation to the crankshaft's TDC-position.
__ But before jumping-ahead to that rather likely possibility, it currently seems that your ign.coil is the prime-suspect. _ So please report-back on that (whenever you can).


Hopeful-Cheers,
-Bob

[Ducatikid]

Bob, I replaced the HT coil today and there still was no spark. So, my next step is to get ahold of the "rebuilder" and see if he "replaced" the stator assembly or "reworked" it. I'm at odds with this problem. There's not, what I would consider, a whole lot to this ignition system as it is rather simple. Since I do have different color leads from the stator, maybe I should be using the red or blue wire for the connection to the HT coil??? What ohm values do I need to see at the end of each color wire??? My reasoning says I have a problem with the stator..........OK, I'm off to the rebuilder for more info! Thanks Bob! Tom

[DewCatTea-Bob]

[quote= Ducatikid ...
" I replaced the HT coil today and there still was no spark. "

____ Did you first confirm that your previous HT.coil's strange test-results were-not also duplicated by your new/replacement-coil ?
Because it's rather doubtful that both ign.coils would be bad (in same or different ways), on-top of another independent problem as well.



" my next step is to get ahold of the "rebuilder" and see if he "replaced" the stator assembly or "reworked" it. "

____ It's more likely that the mag.rotor has not been 'timed' so as to have it producing it's power-output at the particular time when the ign.system needs it.



" Since I do have different color leads from the stator, maybe I should be using the red or blue wire for the connection to the HT coil??? "

____ I'm not sure about the White-colored wire-lead but, others have found that any of the alt.stator wire-leads can manage to provide at-least a weak spark (providing that the rotor is-not out-of-time).



" What ohm values do I need to see at the end of each color wire??? "

____ You should've found that specific info posted within another thread, (wasn't it listed within either of the linked-threads I provided ?).
As I recall, I think the Yellow-wire's resistance-reading to ground is .8 to 1.1 ohm,
the Red-wire's reading is .4 to .7 ohms, and the White-wire's is .2 to .4 ohms.
Please let us know what ohm-measurements YOU read.



" My reasoning says I have a problem with the stator.......... "

____ It's doubtful that your stator-itself is really bad, but more-so likely that it's alt.rotor-flywheel has not been properly 'timed' to the crankshaft.
__ To determine if your alternator is indeed producing some power,, you should hook-up an AC.meter between ground and each of the three wire-leads, (and with the spark-plug removed from the cyl.head), fastly kick-over the engine, so-as to confirm production of AC (on your meter).
____ But first, I'm not yet assured that your choice ign.coils have had any possible issues with them, completely ironed-out.
Can you post any pictures of them or at-least tell some details about them such as what they were originally intended for ?


Hopeful-Cheers,
-Bob

[Ducatikid]

Bob, Yes, you are correct, I didn't need a new coil. The old original is still good! I did get a reply from the rebuilder and he "reworked" the stator. He said the service book (factory?) was incorrect about the stator wiring and he has to find his proper wiring schematic to tell me what is correct on my engine. Thank you for the ohm figures. I'll try to see if I can get a good meter to test with and let you know what I find. Thanks for your patience.......I wish we lived closer.....It would be nice to have someone as knowledgeable as you tutor someone as barely educated in electronics as me !!! I'd never make it with this new technology in all the new bikes today......it's hard for me to grasp all the simple stuff I'm dealing with now! Thanks again Bob. Tom

[Ducatikid]

Bob, Here's my numbers: yellow-.3 ohms, red-.4 ohms, blue-.9 ohms. This is using a Craftsman Autoranging Multimeter (Digital) with new batteries. Ready for further instructions my friend! Tom