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Hello again,

I just did a quick spark test and wanted to get some expert opinions.
I have a magneto (no-battery) system with 2 coils (assuming 6V 40W). I plan to use a simple wiring with one coil feeding the the ignition and the other the lighting.
For the spark plug, I am using a Japanese 6V ignition coil (non-oil) that came from a Honda CB100. I wanted to know if the polarity on the primary winding matters.
When kicking it yesterday, I saw a blue spark on the plug. It wasn't very strong but I imagine that's because I have not set the timing yet. Here are my questions:

1) Is a 6V coil from an early CB100/125 Honda a good choice for my setup?
2) Does the polarity matter on the primary of such coil? and is there an easy way to determine the polarity?

Thanks

-Adrian

[quote= narrow_monza ...
" I have a magneto (no-battery) system with 2 coils (assuming 6V 40W). I plan to use a simple wiring with one coil feeding the the ignition and the other the lighting. "

____ That's as a stock arrangement but,
I guess you have no plans for any brake-light ?



" I am using a Japanese 6V ignition coil (non-oil) that came from a Honda CB100. I wanted to know if the polarity on the primary winding matters. "

____ Whichever terminal-post of the ign.coil is connected to ground, will simply determine which way the spark travels across the spark-plug's electrodes. _ It's considered best for the spark to leave the center-electrode & jump to the grounded-electrode, however the main-job of igniting the fuel-mix is accomplished either way. _ So the chosen hook-up polarity connection is-not really important.



" Is a 6V coil from an early CB100/125 Honda a good choice for my setup? "

____ That that coil is "6v" ought-to indicate that it's intended for a BATTERY-type ign.system, and as such would-not be best suited for your ET/magneto-type ign.system.
However many such small Honda-models (at-least of the '60s) actually employ the same type of ign.system -('Energy-Transfer'), and-so an ign.coil from such a Honda-model ought-to work fairly well.
You just need to find-out if the coil you got, came from a model that's powered by a battery or not. _ And if your chosen ign.coil is meant for a battery-powered ign.system, then I wouldn't expect it to function optimally.
____ Don't you have a stock Green-label ign.coil ?



" is there an easy way to determine the polarity? "

____ If you have a volt-meter which is capable of reading DC.voltages in the 10-50k.range, then you could use it on the HT.coil's secondary-output to determine if the HT.lead has a positive or negative polarity,, and if it's negative, then you know you have the primary-polarity connected-up as it should be intended.


Hopeful-Cheers,
-Bob

My '67 Mark 3 had the stock green coil. The bike always flooded very easily if not kick started just right. Throttle position was critical.
I switched it to an old 6V Honda AC coil I had in the junk box. I'm not sure of the model but probably one of the 60s 100cc bikes.
The bike no longer floods and idles better. Of course it's possible my green coil was defective.

Dave

[quote="DewCatTea-Bob"][quote= narrow_monza ...
" I have a magneto (no-battery) system with 2 coils (assuming 6V 40W). I plan to use a simple wiring with one coil feeding the the ignition and the other the lighting. "

____ That's as a stock arrangement but,
I guess you have no plans for any brake-light ?

Well, I was hoping to dedicate the other half of the generator to headlight+tail light. Not sure how yet. Still in the brainstorming phase.
My top priority at the moment is to get it running. This forum is a great source of valuable info!

[quote= narrow_monza ...
" I was hoping to dedicate the other half of the generator to headlight+tail light. Not sure how yet. "

____ Not sure what you mean exactly.
__ The power-coil which runs the lights is not powerful enough to fully light-up both lights AND the brake-light also, (all during the same time).
So the stock-system taps into the other power-coil (intended for the ign.system), to (rather POORLY) power-up the brake-light.
__ If you rather use a LED.taillight-bulb, then perhaps there'd be sufficient power for lighting-up both taillight-circuits (along-with the std.headlight) from the very-same power-coil.
But if you also have a horn (to be fully street-legal), then you'll need a battery to power it.
__ Do you intend to merely run your Duke in the field/woods nearest your home ?


Dukaddy-DUKEs,
-Bob

DewCatTea-Bob wrote:[quote= narrow_monza ...
" I was hoping to dedicate the other half of the generator to headlight+tail light. Not sure how yet. "

____ Not sure what you mean exactly.
__ The power-coil which runs the lights is not powerful enough to fully light-up both lights AND the brake-light also, (all during the same time).
So the stock-system taps into the other power-coil (intended for the ign.system), to (rather POORLY) power-up the brake-light.
__ If you rather use a LED.taillight-bulb, then perhaps there'd be sufficient power for lighting-up both taillight-circuits from the same power-coil.
But if you also have a horn (to be street-legal), then you'll need a battery to power it.
__ Do you intend to merely run your Duke in the field/woods nearest your home ?

***** Is it possible to install some sort of LED headlight and LED tail+brake light to be powered by the one the generator coils (via some converter circuit) and dedicate the other generator coil to the ignition? The horn can have its own battery (as you suggested) which I would charge when the bike is parked in the garage.
The problem I foresee is that the power will vary widely with rpm. I don't know if such a variable power source can be manipulated to drive LED's.

[quote= narrow_monza ...
" Is it possible to install some sort of LED headlight and LED tail+brake light to be powered by the one the generator coils (via some converter circuit) and dedicate the other generator coil to the ignition? "

____ YES, of-course ! _ And a std.battery would serve as your "converter circuit".
__ Have you forgotten of the related thread-post submitted by Jim last-year ? ... viewtopic.php?f=3&t=1508
Unfortunately back when you posted to that thread,, I then happened to be in the hospital during those days, and-so missed adding my-own post-input in response to you & Jim's posts. _ (I may yet finally get-around to doing so however, some time soon.)
__ Unlike Jim's (rather hastily) chosen scheme-setup however,, with the installation of a battery (instead of a capacitor), you can then rather keep the power-coil originally intended for the ignition-system remaining solely dedicated (to just the ign.circuit only). _ And depending on the size & type of battery chosen, there's really no need for any regulator-unit for taming the relatively low power-output of just one of the power-coils ! - (Jim's setup needs a regulator-unit because he uses a capacitor instead of a battery !)
__ Rather than Jim's capacitor based system,, with a battery based system, you could rather use a single 'diode' (instead of a bridge-rectifier) connected to just one wire-lead from the power-coil, to keep the battery charged.
And then the battery would power ALL your LED.lights !
__ But don't forget that there are many other options which you may prefer !



" The horn can have its own battery (as you suggested) which I would charge when the bike is parked in the garage. "

____ Why bother with such such a total-loss setup, when the power-coil intended for the ign.system makes far more power than the ign.system can possibly make use of !?
It's quite simple to tap into some of the power that's otherwise totally WASTED by the ign.points, and rather divert it to keep a battery charged !



" The problem I foresee is that the power will vary widely with rpm. I don't know if such a variable power source can be manipulated to drive LED's. "

____ Well if you expect to include a std.battery, (which maintains it's system voltage-level !),, then rather steady powering of LEDs, would be no-problem anyway,
right ?


Hopeful-Cheers,
DCT-Bob

If I understand correctly, the following scheme should get me started. The headlight and tail/brake light would be LED-based if needed.
The rectifier/regulator would be the same one Jim used on his set up (Podtronics).
I would appreciate any feedback.

Thanks

-Adrian

[quote= narrow_monza ... " If I understand correctly, the following scheme should get me started. "

____ Well Adrian, it seems you've come-up with one of the many options for an alternate/non-stock electrical-system, all on your-own. _ However your scheme-diagram isn't without a number of concerns...
First, you have the ign.coil connected-up wrong,, and a std.type horn-button can't work on the positive-side of the horn where you've displayed it.
Also, I thought your two stator-coils were BOTH grounded !? _ So with one depicted as no-longer grounded, it's now uncertain as to which stator-coil is supposed to be which. _ Do you intend to still have the ign.power-coil connected to the ign.coil ?
And another thing you should try to understand, is that a regulator-circuit is only useful for when the alternator can produce sufficient power to overcharge the chosen battery. _ And since the output of just one power-coil will be near a balanced-state for your load-system, an expensive regulator-unit is-not needed (along-with the system-regulation effect of a std.battery),, and-so all you actually need is just a 3-buck bridge-rectifier (in place of your depicted rectifier/regulator-unit) !



" The headlight and tail/brake light would be LED-based if needed. "

____ In order to maintain sufficient battery charging (with lights left turned-on),, a std.taillight-bulb would likely need to be substituted with a LED.type replacement bulb, (although the stock 25w.headlight-bulb should remain supportable).
__ However if you choose to keep the ign.system from wasting the power that it short-circuits to ground, and rather divert it towards helping to charge the battery,, THEN, you'd then have more than enough power to power-up all the stock-type lights AND keep the battery well charged-up, as well !



" The rectifier/regulator would be the same one Jim used on his set up (Podtronics). "

____ What's YOUR reasoning for needing such as that ?
__ As I've already mentioned,, since Jim rather chose to employ a 'capacitor' (instead of a battery), his particular setup REQUIRES a regulator-unit only because capacitors store-up peak-voltage and don't maintain normal system-voltage like a std.battery does !
And since your intended power-source is barely able to match your intended load-system*, (let-alone that it's unable to also overcharge your battery as well),, NO power-regulation is really called-for !
(* Unless it's all with LED.type lighting.)


Cheers,
-B.
(I expect to add more stuff later.)

DewCatTea-Bob wrote:[quote= narrow_monza ... " If I understand correctly, the following scheme should get me started. "

____ Well Adrian, it seems you've come-up with one of the many options for an alternate/non-stock electrical-system, all on your-own. _ However your scheme-diagram isn't without a number of concerns...
First, you have the ign.coil connected-up wrong,, and a std.type horn-button can't work on the positive-side of the horn where you've displayed it.
Also, I thought your two stator-coils were BOTH grounded !? _ So with one depicted as no-longer grounded, it's now uncertain as to which stator-coil is supposed to be which. _ Do you intend to still have the ign.power-coil connected to the ign.coil ?

***** Bob, you are correct. I do have both stator-coils grounded and only a single wire coming out of each. I thought I needed to rewire it and "un-ground" one of the stator-coils as depicted in my diagram in order to use the Podtronics Rectified/Regulator. However, if there's a way I can use the stator in its existing configuration (both coils grounded) in a battery-assisted wiring scheme, that would save me the hassle of removing the stator.

And another thing you should try to understand, is that a regulator-circuit is only useful for when the alternator can produce sufficient power to overcharge the chosen battery. _ And since the output of just one power-coil will be near a balanced-state for your load-system, an expensive regulator-unit is-not needed (along-with the system-regulation effect of a std.battery),, and-so all you actually need is just a 3-buck bridge-rectifier (in place of your depicted rectifier/regulator-unit) !

***** OK so it sounds like an even simpler scheme (with a battery and a bridge-rectifier) could work with my existing 2-wire magneto?
Here's a an area I'm unclear about: What does the output on each of the single "hot" wires look like out of my magneto? Is it a full 6V sine wave out of each of the stator-coils? Or is it a half 6V sine wave (since the other end of each of my stator-coils is grounded)?