Spark quality and coil questions

[narrow_monza]

[quote= narrow_monza ...
" here's a schematic I drew (attached). Please provide some feedback "
____ First I must say that you've drawn-up a quite nicely done schematic-diagram, (although it's 'scheme' isn't the best) !

Thank you. At least it looks good, as for the content, it's a work-in-progress.

__ There's a couple concerns with your wiring-scheme needing to be addressed...
First,, is that your horn-button/switch, (assuming will be handlebar-mounted), needs to be repositioned on the ground-side of the horn.

For a normally-off switch? Why is that?

Next,, was this scheme of yours conceived before I posted concerns about your weak-spark with your Jap.ignition-coil ? _ Cuz your scheme shows the ign.coil wired-up as if rather within a battery-powered ign.circuit-type ! _ Yet I had expected that you've understood my post concerning the particular way that Ducati's magneto-type ign.circuit is actually connected-up.
So is this aspect-point of your drawing an ERROR, or did you find that your ign.coil's resulted ign.spark started better with this indicated ign.coil-connection ?
Does this drawing of yours presently correctly-represent your chosen wiring-connection to the ign.coil, as you've had your engine running ??

This is the only way I tried connecting the ignition coil so far. I must have missed the following comment you posted a few days ago:

However with your non-stock/Jap.coil, you could also try-out circuit-wiring it in a (more common) SERIES-circuit with the ign.points. _ This circuit-arrangement will rather create it's ign.spark due-to a SUDDEN collapsing flux-field (instead of the mere rapidly-expanding field). _ However, (even-though the resulted ign.spark is sufficient to run the engine), it's been my experience that various ign.coils merely create a somewhat weaker spark THAT-way (with pulsed-DC). _ So rather than having-to depend-on the collapsing-field of merely-just a single pulse of DC,, instead, you could rather store-up the other three (otherwise ignored & wasted) neg.DC-pulses and retain the combined energy of ALL-four neg.power-pulses (per Otto-cycle) stored into a capacitor, so as to 'filter' all those (originally separate) DC.pulses combined-together into rather 'straight-DC' and thus-then build-up a stronger & better-established flux-field before collapsing, to create a considerably stronger ign.spark.

Is that what you are referring to? If so, I will try out the SERIES scheme described above.
What type of capacitor should I be using (unless you are were suggesting re-wiring the existing points condenser(?))

Thanks

-Adrian

[DewCatTea-Bob]

____ Well Adrian, here it is now nearly 12-hours later, well-after you submitted your last-post placed on THIS-page ! _ While I just-now found it for the first-time,, since I've been staying on page-4 cuz I didn't happen to notice that this new-page had been created, (as I had-not been realizing at-all, that page-4 had already become filled-up with it's 10-post limit). ...
I had been sitting on page-4, refreshing it a few times and not seeing any new-posts following mine, and-so just assumed that the thread was simply remaining inactive (except for my-own activity). _ Stupidly though (until now), it didn't cross my mind before to check & see if the thread had grown still another page already ! _ So here I am just now finally getting to it !
__ Likewisely as-well, the creation of this new page has also had the effect of diverting any others from opening page-4 and noticing the fact that I've finally-finished my last post back-there ! - (As I note that my posted-diagram has [so far] been left unnoticed !)




[quote= narrow_monza ...
" as for the content, it's a work-in-progress. "

____ Of-course I had expected so.



" For a normally-off switch? Why is that? "

____ Because ordinary/regular std.horn-button/switches simply ground their single wire-lead/circuit directly to the handle-bar, only !



" This is the only way I tried connecting the ignition coil so far. "

____ You mean in the 'series' fashion, as depicted in YOUR scheme-diagram ?
Perhaps your non-stock Jap.coil is rather compatible with that series-type circuit-arrangement, but it's certainly an experimental-status setup for working along-with Ducati's ign.power-coil !
__ That type of connection is-not a standard circuit for use with pulsed-DC !
While it may be sufficient enough for low-RPM,, at higher RPMs, the dwell-time for properly saturating the ign.coil will become too short to continue producing an adequate spark (and likely misfiring will then occur).



" Is that what you are referring to? "

____ While that stuff you've quoted is somewhat also related (to that which I had expected you to have been understanding),, I was more specifically meaning to refer to Ducati's-own INTENDED ign.coil-circuit for their magneto-type ign.system and how it may seem to appear to be little-more than a short-circuit (to those who are only familiar with battery-powered type ign.systems with the series-type connection).
Having assumed that you were understanding everything and-thus fully on-track, I had thusly expected that you had had the ign.circuit properly connected-up just like the stock/Ducati-way* (when you mentioned your noted weak-appearing ign.spark). - (* See my posted version of your posted scheme-diagram [on the previous-page].)
But misconceptions like this are bound to happen when MY questions aren't directly replied to (as like I do those of others').
I guess we should've had you post a circuit-diagram of exactly how you had your wiring-connections circuited, SOONER.



" I will try out the SERIES scheme described "

____ But the only difference between that and what you've indicated in your posted diagram, is the addition of a rather large storage-cap.
It seems that you've already been trying-out the SERIES-scheme and have been ignoring the original/STOCK parallel-arrangement -(as can be seen in my altered-version of your posted scheme-diagram). - (If you can, you ought-to download & print-out a copy of MY-version for you to keep handy for study, [and ask any questions that come-up concerning it].)



" What type of capacitor should I be using "

____ Unless you wish to covert-over to rather straight-DC.powered type of ignition, you won't require the type of storage-cap referred-to.
This 'battery-eliminator' type of capacitor has been extensively covered before,, and-so if you're really interested, then let me know and I'll then post a related link.



" (unless you are were suggesting re-wiring the existing points condenser(?)) "

____ I've been rather lost as to whether you had already had the 'series' ign.circuit wired-up all on your-own, originally,, or if you later tried it out only after I made the suggestion to give it a try with your Jap.coil.
So 'yes', I did mean to suggest that whichever way you already have the points & ign.coil arranged, ('series' or 'parallel'),, try switching it around and compare the two arrangement-schemes, (for both starting & high-RPM performance).
__ BTW, can you post a pic of your Jap.coil ?


Hopeful-Cheers,
-Bob

[narrow_monza]

Hi Bob,

Sorry for the mix up. We got out of sync. Let me try to summarize where I'm at now.
Please refer to the attached schematics labeled (1) and (2).
For both schemes, the bike starts and seems to idle ok.
Next I plan I on trying the corrected wiring scheme you posted on page 4 (probably without the battery, horn, and tail light).

I'm also attaching a photo of the Japanese 6V ignition coil. It's made my Mitsubishi and is meant for small capacity Honda's of the early 70's.

Thanks

-Adrian

[DewCatTea-Bob]

[quote= narrow_monza ...
" We got out of sync. "

____ I guess it's originally my fault for ASSUMING that you had first started-out with Ducati's intended electrical-scheme for their NON-battery-powered ign.circuit. _ And I guess you didn't realize what I was actually referring-to, and-so didn't correct me.



" Please refer to the attached schematics labeled (1) and (2).

____ Both have the ign.coil & points connected in the same series-fashion as if meant connected to a straight-DC power-source.



For both schemes, the bike starts and seems to idle ok. "

____ So far as I know, no manufacturer tries to make-use of an ignition-coil's collapsing-field after being created merely by just a single DC.pulse (supplied from a mag.rotor). _ And that's because an ign.coil's flux-field needs TIME to get fully established before it's collapse can generate enough energy to yield sufficient sparking-power,, and at high-RPMs, the time for establishing a usable field becomes insufficient, (as the tapped DC.pulse's life-span linearly shrinks as RPM increases).
__ So if you try running a high-RPM test, you'll then quite possibly encounter engine cut-out & misfiring.



" I plan I on trying the corrected wiring scheme you posted on page 4 "

____ The section of it pertaining to the ign.circuit depicts the magneto-type ignition-system setup that Ducati expected the ign.power-coil to run. _ And with the points rather connected in parallel (rather than series) with the ign.coil,, the closed points short-circuit the supplied power-juice away-from the ign.coil and directly to ground, which allows maximum current to be passed-through the power-coil and-thus also create a flux-field around IT-self _ And when the points open, the then established current has to detour through the resistance of the ign.coil but the current-amperage can't accordingly decrease because the flywheel-effect of the collapsing-field around the power-coil won't immediately allow the amperage to decrease, which thusly SHOCKS the ign.coil with a sudden shot of power-juice that RAPIDLY creates an expanding*flux-field within, which in-turn creates it's resulted intensified 'spark' !
(* This is why the magneto-powered ign.system is called an 'energy-transfer' system.)
__ So in this case,, as the revs climb, the produced power-juice gets stronger & STRONGER which in-turn so does the related effects that make the ign.spark stronger as well ! _ So this 'parallel' arrangement thrives with increased RPM,, rather than reach a diminishing petered-out status, as the series-arrangement does.



" the Japanese 6V ignition coil.
is meant for small capacity Honda's of the early 70's. "

____ I'm not real sure but, I think at-least some of those small Honda-engines employed ET.ignition-systems, in which case the associated ign.coils ought-not be any specific 'voltage' as if to rather be DC.powered by a 6v.battery.


Duke-Cheers,
-Bob