Starter switch on 67 Scrambler

[Adam]

Does anyone have photos of what the connections of the ignition switch inside the headlamp should look like when the key is turned on and off? The tabs dont seem to be connecting as there is no spark when connected according to the diagram. I've had to bypass the switch altogether (rerouting the green wire) to get the motorcycle to start. I've verified continuity from the block to each terminal in the switch.
-Adam

[DewCatTea-Bob]

Does anyone have photos of what the connections of the ignition switch inside the headlamp should look like when the key is turned on and off? The tabs dont seem to be connecting as there is no spark when connected according to the diagram. I've had to bypass the switch altogether (rerouting the green wire) to get the motorcycle to start. I've verified continuity from the block to each terminal in the switch.
-Adam

____ How about a picture of what you have ?
Cuz "67 Scrambler" is-not descriptive enough.


Hopeful-Cheers,
-Bob

[Adam]

67 Scrambler(NC) received from my uncle about 5yrs ago, previously owned by my dad who bought it used back in 69/70. Finally got it to idle although it sounds rather high. Let me know if you need more pics. I have plenty more

[DewCatTea-Bob]

[quote= Adam ...
" 67 Scrambler(NC) "

____ While it may've been sold sometime in 1967,, it's actually a 1966-model, as that was the only model-year for that battery-equipped n-c.250-Scrambler !



" Let me know if you need more pics. "

____ Thanks for the pair of high-quality pix you've already posted of your key-ign.switch !
I've altered them for hopefully improved comparative viewing, (as now seen below).

Does anyone have photos of what the connections of the ignition switch inside the headlamp should look like when the key is turned on and off?

____ Your magneto-ign.type key-switch is the stock type (that came only on the 1966-Scrambler [& all 160s]).
That key-switch's on/off-circuits are unique in that whilst it connects -(closes) one independent/isolated-circuit, at the same-time it also then concurrently disconnects -(opens) another !
So when the key is out, the switch defaults to close a circuit that shorts-out the magneto-power to the ign.coil, thus keeping the engine from being powered-up.
And when the key is inserted into it's ON-position,, then not-only is the ign.power-circuit no-longer short-circuited to ground, but also the battery-power then becomes connected & available to the main load-system too-boot, (just as expected like most-all other regular key-switches) !

The tabs dont seem to be connecting as there is no spark when connected according to the diagram.

____ Have you by any chance previously had the key-switch wiring completely disconnected and then later reconnected just according to what you've understood some-diagram -(that might rather be in reference to a non-mag.type key-switch/ign.system), seemingly indicating ?
Cuz the ign.spark should rather be functional only when the key-switch's ign.circuit connection-tabs are DISconnected !

I've had to bypass the switch altogether (rerouting the green wire) to get the motorcycle to start.

____ The green/kill-wire normally runs-back from the ign.switch's grounding-circuit to the ign.coil's mag.powered points-terminal,, and it need not be 'rerouted', but rather merely-just isolated in order for the defaultly-connected magneto-ign.system to be allowed to fire-up.
So I sure hope you didn't 'reroute' that green-ign.switch-wire to any circuit that's in any way connected to any battery-circuit ! - (As I've come-across more than one 66-Scr.Duke of which their tinkering owner had burnt the magneto-ign.coil by trying to get ign.spark with directly fed power-assistance from a battery-circuit ! Apparently having not realized that their Duke's ign.system was-not meant to be run with the battery.)

I've verified continuity from the block to each terminal in the switch.

____ So-then I gather that you indeed may-not have realized that there really should-not be continuity to ALL-4 of the switch's terminals (regardless of either switch-position).
However I'm not really sure of what your stated-wording may've actually meant to specifically convey. _ But there should-not be any continuity between the two pairs of switch-terminals, as each of their respective circuits are supposed to be ISOLATED from one-another !



____ Your pictured switch appears to be in proper working-order, so it seems that you-yourself have actually provided the very pictures which you had requested of others ! _ (And you likely couldn't have had them made any-much better elsewhere either, for that matter.)
__ Anyhow, since your key/ign.switch wiring connections are now pictured all hooked-up correctly, and the switch itself is apparently not a valid suspect,, please follow-up with what you now think might still be wrong with whatever may be the actual cause of your presented concern. ...
At this point,, I'd be most inclined to suspect something along the lines of you having not properly connected-up the magneto-ign.scheme wiring, as it ought normally be. _ And perhaps instead, you've possibly got the green-wire's other end rather connected to the ign.coil's normally directly-grounded terminal, (instead of it's ign.points-terminal). (?) _ As such mis-wiring/circuiting is a fairly common misconception, since the stock magneto-ign.circuit does sorta seem nonsensical to most-all who are only readily familiar with the std.battery-powered ign.circuit,, (as seems to also be the same situation in your case as well, since you were in wonderment as to why your ign.switch doesn't seem to have your-expected connection-continuity between it's ign.circuit contact-tabs).


Hopeful-Cheers,
DCT-Bob

[Ventodue]

Hi Adam,

All good stuff from Bob, of course . Just do this little test, using the resistance function on your multi-meter:

1. With the key OUT: you should have a circuit between the post with the green wire and the post with the black wire. There should be no circuit between the other two posts.

2. With the key IN (and turned): you should now have a circuit between the two posts with the brown wires. But there should be NO circuit between the post with the green wire and the post with the black wire.

These switches are pretty robust. Just make sure all the cables and their attachments are good and clean - and you may have to manipulate the spring contacts a little. But that's normally all.

HTH

Craig

[Adam]

Hi Adam,

All good stuff from Bob, of course . Just do this little test, using the resistance function on your multi-meter:

1. With the key OUT: you should have a circuit between the post with the green wire and the post with the black wire. There should be no circuit between the other two posts.

2. With the key IN (and turned): you should now have a circuit between the two posts with the brown wires. But there should be NO circuit between the post with the green wire and the post with the black wire.

These switches are pretty robust. Just make sure all the cables and their attachments are good and clean - and you may have to manipulate the spring contacts a little. But that's normally all.

HTH

Craig

Hi Craig
I finally found my multimeter and followed your recommendations. Key Out showed some resistance between the green and black post between .1 - .3 while the brown wires had no reading.
Key In between the brown wires varied considerably with each reading however, the black and green posts had no reading.

-Adam

[Adam]

[quote= Adam ...
" 67 Scrambler(NC) "

____ While it may've been sold sometime in 1967,, it's actually a 1966-model, as that was the only model-year for that battery-equipped n-c.250-Scrambler !

****Thanks for confirming that! Between what my relatives told me and comparing the serial number to other posts pointed me to '67.

The tabs dont seem to be connecting as there is no spark when connected according to the diagram.

____ Have you by any chance previously had the key-switch wiring completely disconnected and then later reconnected just according to what you've understood some-diagram -(that might rather be in reference to a non-mag.type key-switch/ign.system), seemingly indicating ?
Cuz the ign.spark should rather be functional only when the key-switch's ign.circuit connection-tabs are DISconnected !

****No, I left everything intact. The wiring in the headlamp looks pretty good so I left it alone. I did have to tie into the existing three wires from the magneto as they were in pretty bad shape. I'd like to replace those three wires altogether but I'm hesitant to crack open the case.

I've had to bypass the switch altogether (rerouting the green wire) to get the motorcycle to start.

____ The green/kill-wire normally runs-back from the ign.switch's grounding-circuit to the ign.coil's mag.powered points-terminal,, and it need not be 'rerouted', but rather merely-just isolated in order for the defaultly-connected magneto-ign.system to be allowed to fire-up.
So I sure hope you didn't 'reroute' that green-ign.switch-wire to any circuit that's in any way connected to any battery-circuit ! - (As I've come-across more than one 66-Scr.Duke of which their tinkering owner had burnt the magneto-ign.coil by trying to get ign.spark with directly fed power-assistance from a battery-circuit ! Apparently having not realized that their Duke's ign.system was-not meant to be run with the battery.)

****I had referred to the electrical schematic for Scrambler 250 from e.n. 92712. It shows the green going from the block (opposite the yellow wire) up to the key switch, then returning to the HT Coil. I simply took it from the block to the coil keeping the return intact. I'll post the schematic that shows this. I currently do NOT have any battery connected to this system. I do plan on putting one in once the wiring is put back according to the schematic.

I've verified continuity from the block to each terminal in the switch.

____ So-then I gather that you indeed may-not have realized that there really should-not be continuity to ALL-4 of the switch's terminals (regardless of either switch-position).
However I'm not really sure of what your stated-wording may've actually meant to specifically convey. _ But there should-not be any continuity between the two pairs of switch-terminals, as each of their respective circuits are supposed to be ISOLATED from one-another !

****Please bear with me as I am new at this. Ventodue elaborated on the procedure for testing this out. I've answered his post with my findings.

____ Your pictured switch appears to be in proper working-order, so it seems that you-yourself have actually provided the very pictures which you had requested of others ! _ (And you likely couldn't have had them made any-much better elsewhere either, for that matter.)

****That's the iPhone 6 for ya.

__ Anyhow, since your key/ign.switch wiring connections are now pictured all hooked-up correctly, and the switch itself is apparently not a valid suspect,, please follow-up with what you now think might still be wrong with whatever may be the actual cause of your presented concern. ...
At this point,, I'd be most inclined to suspect something along the lines of you having not properly connected-up the magneto-ign.scheme wiring, as it ought normally be. _ And perhaps instead, you've possibly got the green-wire's other end rather connected to the ign.coil's normally directly-grounded terminal, (instead of it's ign.points-terminal). (?) _ As such mis-wiring/circuiting is a fairly common misconception, since the stock magneto-ign.circuit does sorta seem nonsensical to most-all who are only readily familiar with the std.battery-powered ign.circuit,, (as seems to also be the same situation in your case as well, since you were in wonderment as to why your ign.switch doesn't seem to have your-expected connection-continuity between it's ign.circuit contact-tabs).

****Take a look at the schematic I've posted. I colored it for my own benefit while tracing wires. Black or white wires were left as is and labled instead. 17 & 18 in the headlamp are the indicator light(18 is e is actually missing). While connected originally, I would not get any spark with key pushed in. Once the switch was removed from the equation, I got spark right away. I cleaned the terminals of the switch this evening. If that doesn't work, then I'll run a new green wire to the switch.

Thanks

-Adam

[DewCatTea-Bob]

____ Your follow-up post is appreciated Adam ! - (It seems I had falsely jumped-to-conclusion on more than one aspect of your troubleshooting-case, and-so now your updated post-info conveniently curves me from still further mis-speculation.)
____ Anyhow, firstly I must explain that I've edited your post only in that I've properly incorporated the intended-use of the 'Quote' feature that's provided for visually separating our respective post-writings in the normally expected organized manor.



" Between what my relatives told me and comparing the serial number to other posts pointed me to '67. "

____ Many '66-Scramblers with 6-didgit motor-numbers (such as 101234 weren't sold & titled until 1967, and-so were considered as 1967-models, although actually made in 1966.

____ Have you by any chance previously had the key-switch wiring completely disconnected and then later reconnected just according to what you've understood some-diagram seemingly indicating ?

"****No, I left everything intact. The wiring in the headlamp looks pretty good so I left it alone. "

____ I had overlooked to include within my previous-posting that the picture of your key-switch's ign.circuit connections only included just one green-wire ! ...
Ducati's (wire wasteful) wiring-scheme has one green-wire (that's connected to the yellow mag.stator-wire), which directly runs-up to the key-switch's ign.circuit input-terminal,, at which point, another length of green-wire runs-back from that very-same switch-terminal to the ign.coil's power/points-terminal.
So one-half of that entire green-wire power-circuit seems to somehow be missing from your wiring-system,, and without the wiring-alteration you made to compensate for that shortcoming, the ign.spark indeed could-not have fired before, (meaning just-before that wiring "rerouting" you did).
__ So this leads to the following questions...
Which-one of the two green power-wire/circuits is the actual-one that's been disconnected from the k.switch-terminal,, the green-length from the mag.stator's yellow-wire, or, the green-length going-back to the ign.coil ??
How long has the ign.spark actually not been firing, (since the time when someone-else must've messed-around with the green-wiring ?) ? _ (I had previously assumed that you were simply troubleshooting an ign.system which had been working until a relatively recent malfunction befell it, but it's not a common-happenstance for such malfunction to develop due-to a length of wire coming-up missing from the wiring-system ! _ So I'm thus left to assume that you have taken-up where someone-else had left-off on an unfinished endeavor with the wiring-system. [?])



" I did have to tie into the existing three wires from the magneto as they were in pretty bad shape. "

____ It's a common-problem for the insulation-jacket/coating of those original crummy/crumby wire-leads to disintegrate.



" I'd like to replace those three wires altogether but I'm hesitant to crack open the case. "

____ Unless you also have another reason to get inside there, it's just as well for you to leave those wires left undisturbed,, as they'll still continue performing their function well enough, (so long as left-be).

____ The green/kill-wire normally runs-back from the ign.switch's grounding-circuit to the ign.coil's mag.powered points-terminal,, and it need not be 'rerouted', but rather merely-just isolated in order for the defaultly-connected magneto-ign.system to be allowed to fire-up.

" ****I had referred to the electrical schematic for Scrambler 250 from e.n. 92712. It shows the green going from the block (opposite the yellow wire) up to the key switch, then returning to the HT Coil. "

____ Right, I'm sorry,, my quoted wording was fairly misleading, as it's that particular separate*green-length from the connector-block going up to the key-switch that I had previously overlooked & forgot-about and-also failed to fully contemplate and include mention of, (due-to the absence of the second green-wire in your key-switch pic) !
__ (* That extra length of green-wire to the key-switch was pretty-much unnecessary for Ducati to have included, as only one length going the headlamp-route [between the ign.coil & k.switch] is actually required !)
This Ducati-circuit oddity has already been covered a couple times before in old threads concerning stock '66-Scr & 160-M.Jr electrical-schemes, and I also then certainly made-point that the primary green-wire should rather be left yellow-colored and rather directly-connected to the ign.coil (for all the obvious functional reasons) ! _ And it seems you've also realized the good-sense of this simple circuit-mod on your-own, as well.



" I simply took it from the block to the coil keeping the return intact. I'll post the schematic that shows this. "

____ I see from your drawing-modifications to the stock scheme-diagram that you've indeed simply jump-connected the stator's yellow-wire (with your added ghost-green jumper-line) to the power/points-terminal of the ign.coil ! _ And that's exactly how Ducati should've done it in the first-place, so as to simplify the wiring-scheme and current-pathway (and-also save a length of green-wire) !
So now your green-length which you've left intact, can be left connected between the ign.coil & key-switch and function as the 'kill-wire' like I had expected.

__ Anyhow, since your key/ign.switch wiring connections are now pictured hooked-up correctly, and the switch itself is apparently not a valid suspect,, please follow-up with what you now think might still be wrong with whatever may be the actual cause of your presented concern.

" Take a look at the schematic I've posted. I colored it
While connected originally, I would not get any spark with key pushed in. Once the switch was removed from the equation, I got spark right away. "

____ I see that besides coloring the pertinent green-wiring,, you've also left a length of it not-only uncolored, but also Xed-out as well ! _ What's the reason for that, exactly ? _ Is yours missing, or what ?
If missing, then that's got to be compensated for,, or-else guess-what, there can't be any mag.power conducted to the ign.coil !
Or maybe rather, perhaps you (elaborately) pulled-out the missing green-wire from out-of the headlamp-harness and-then rather directly-connected -('rerouted') it straight-to the ign.coil ?
I guess that could explain your posted specific scheme-changes indicated for your altered green circuit-pathway,, AND-also, likely explain why your key-switch pictures don't include showing the missing green-wire !?
____ I'm wondering exactly what-all you've since altered (intentionally or not) from how everything was "connected originally",, that your Duke hadn't before possessed any spark, back-then !? _ In other-words, if you were to reverse everything you've done, one change at a time,, would your previous ign.issue ever come-back, or not ? _ I wonder about such because your ignition-issue shouldn't have developed all on it's-own, and-also shouldn't be so simply fixed by merely-just "rerouting" the green/power-wire & it's connection away-from the k.switch-terminal and-to the ign.coil, (without something-else being changed as well) !
Was it yourself, or someone-else previously,, who apparently altered some of the factory green-wiring, (as is indicated by your Xed-out green-length) ?
__ I'm thinking that it really wasn't actually the removal of the key-switch from the circuitry that seemingly changed your results, but rather that the magneto-power of the yellow/green-circuit wasn't properly getting normally circuited up-to the k.switch in the first-place (so that the mag.power could then continue-onward back-to the ign.coil) !



" I cleaned the terminals of the switch this evening. "

____ If you also included the switch connector-tabs and your effort was actually fruitful, then expect no-more than .1-ohm between it's contacts.



" If that doesn't work, then I'll run a new green wire to the switch.

____ That would more-likely result with providing the desired effect ! _ However, as should be obvious,, you really only need just one green-wire/circuit (to connect between the ign.coil & k.switch) !
So I suggest that you merely just retain your jumper-wire/connection between the yellow/power-wire & ign.coil, (and-also of-course continue with the stock employment of the single green-wire/circuit from the ign.coil to the [properly grounded] k.switch ground-circuit).
That way, you then certainly won't have-to depend on the apparently missing green-wire/power-circuit (that's UNnecessarily detoured up-into the headlamp before continuing-on back-to the ign.coil) !
As it seems at this-point, that it's that (presently inexplicably)- failed green-circuit which has prevented your ign.system from powering-up.


Hopeful-Cheers,
DCT-Bob

[Ventodue]

Hi Craig
I finally found my multimeter and followed your recommendations ... <snip>

Good Adam - it seems the switch is working correctly *. For the rest, well, I reckon Bob has told you what's not right/missing - and what's more, how to fix it!

Ciao

Craig

* Altho' you should work to improve the connection between the two brown posts, to get it working consistently. But hopefully your cleaning will already have done this!

[Adam]

____ I had overlooked to include within my previous-posting that the picture of your key-switch's ign.circuit connections only included just one green-wire ! ...
Ducati's (wire wasteful) wiring-scheme has one green-wire (that's connected to the yellow mag.stator-wire), which directly runs-up to the key-switch's ign.circuit input-terminal,, at which point, another length of green-wire runs-back from that very-same switch-terminal to the ign.coil's power/points-terminal.
So one-half of that entire green-wire power-circuit seems to somehow be missing from your wiring-system,, and without the wiring-alteration you made to compensate for that shortcoming, the ign.spark indeed could-not have fired before, (meaning just-before that wiring "rerouting" you did).
__ So this leads to the following questions...
Which-one of the two green power-wire/circuits is the actual-one that's been disconnected from the k.switch-terminal,, the green-length from the mag.stator's yellow-wire, or, the green-length going-back to the ign.coil ??
How long has the ign.spark actually not been firing, (since the time when someone-else must've messed-around with the green-wiring ?) ? _ (I had previously assumed that you were simply troubleshooting an ign.system which had been working until a relatively recent malfunction befell it, but it's not a common-happenstance for such malfunction to develop due-to a length of wire coming-up missing from the wiring-system ! _ So I'm thus left to assume that you have taken-up where someone-else had left-off on an unfinished endeavor with the wiring-system. (?)

****It's been a while since i did that ( lots of shiny objects distracting me since then). After reviewing, the previous owner pretty much had the same idea; one wire connected at the HT Coil. Connection must have been bad. There is actually no 2nd green wire going to the key switch. Also, the black wire going from the coil to the points system(not mentioned earlier) was crudely twisted together and taped up. This was in bad shape (rusted) and replaced by me at the time I worked on the green wire.

____ I see that besides coloring the pertinent green-wiring,, you've also left a length of it not-only uncolored, but also Xed-out as well ! _ What's the reason for that, exactly ? _ Is yours missing, or what ?
If missing, then that's got to be compensated for,, or-else guess-what, there can't be any mag.power conducted to the ign.coil !
Or maybe rather, perhaps you (elaborately) pulled-out the missing green-wire from out-of the headlamp-harness and-then rather directly-connected -('rerouted') it straight-to the ign.coil ?
I guess that could explain your posted specific scheme-changes indicated for your altered green circuit-pathway,, AND-also, likely explain why your key-switch pictures don't include showing the missing green-wire !?

****I X'd that out for my purposes. While tracing the wires ( everything is covered in the harness) I assumed the 2nd green wire was in there somewhere so to avoid confusion later, I indicated that it is currently not being used. After reviewing it again recently, it looks like it is only one wire that is joined by a connector at the coil post. I had replace this with a fresh wire from the block to the coil.

____ I'm wondering exactly what-all you've since altered (intentionally or not) from how everything was "connected originally",, that your Duke hadn't before possessed any spark, back-then !? _ In other-words, if you were to reverse everything you've done, one change at a time,, would your previous ign.issue ever come-back, or not ? _ I wonder about such because your ignition-issue shouldn't have developed all on it's-own, and-also shouldn't be so simply fixed by merely-just "rerouting" the green/power-wire & it's connection away-from the k.switch-terminal and-to the ign.coil, (without something-else being changed as well) !
Was it yourself, or someone-else previously,, who apparently altered some of the factory green-wiring, (as is indicated by your Xed-out green-length) ?
__ I'm thinking that it really wasn't actually the removal of the key-switch from the circuitry that seemingly changed your results, but rather that the magneto-power of the yellow/green-circuit wasn't properly getting normally circuited up-to the k.switch in the first-place (so that the mag.power could then continue-onward back-to the ign.coil) !

****You might be right in this aspect. I didn't change one thing at a time during this process to pinpoint the issue, rather just replace what I thought needed fresh connections. I think redoing the black wire to the points also helped.

____ That would more-likely result with providing the desired effect ! _ However, as should be obvious,, you really only need just one green-wire/circuit (to connect between the ign.coil & k.switch) !
So I suggest that you merely just retain your jumper-wire/connection between the yellow/power-wire & ign.coil, (and-also of-course continue with the stock employment of the single green-wire/circuit from the ign.coil to the [properly grounded] k.switch ground-circuit).
That way, you then certainly won't have-to depend on the apparently missing green-wire/power-circuit (that's UNnecessarily detoured up-into the headlamp before continuing-on back-to the ign.coil) !
As it seems at this-point, that it's that (presently inexplicably)- failed green-circuit which has prevented your ign.system from powering-up.

****I will give it a try this weekend and add the result to this post. Thanks for your help.

-Adam