Installing Electrex World Stator System on Diana

[Harvey]

[quote= Nick ...
" What sort of ballast resister should I use? "

____ Here's a link to other posts (placed here in the past), on the topic...
search.php?keywords=BALLAST+RESISTOR
It's likely within those two pages, you'll find useful related-info of interest to you.



" And where does one find them? "

____ Auto.parts-stores, probably eBay as well.
Hopefully someone-else here, who has bought a modern unit,, will offer advice on a best-choice.



" I suppose the resister should be wired between the points wire and the coil? "

____ That should work just as well but, most get installed between the ign.switch's output & the ign.coil.
Their intended-function is to help allow the ign.spark to be stronger for cold-starting,, and after it becomes warmed-up, it THEN develops resistance to spare the ign.coil from becoming overheated, (as by then, the engine doesn't require as strong of a spark, since it's then also warmed-up).
__ If you have a rather strong ign.coil (of any primary voltage-rating), then you could take-advantage of the benefit of a much larger plug-gap, upwards of as much as 2mm -(60 to 80 thousandths, instead of only .028") ! _ (Or, .035" to .040" gap, along-with a plug-cap like that seen on 'Philly Throttle' last night.)


Hopeful-Cheers,
-Bob

Bob you got me intrigued again.
Firstly as he is using a 12V coil on as 12V system, there is no need for a ballast resistor, as it will only reduce the coils output.
Ballast resistors were used on Auto systems in series with a 10V coil.
The action was that when the starter was used, it pulled the battery voltage down to around 10 to 11 volts, so the coils output was reduced. With the series resistor included, when the starter is running, the resistor is by-passed, so the 10V coil will run on the battery’s reduced voltage, to provide a good spark, when the started is off, the series resistor is again included in the circuit to reduce the 12V down to the coils 10V.
Some of the latter systems, using coils of less than 1 ohm use a ballast to control the coils current flow.

The second part is maybe your “tongue in cheek” reference to the TV show that you mention, that I did not see, but it would be sheer madness to open the plug gap up to those gaps. It is not needed and will only cause the higher voltage to short out anywhere and everywhere it can, unless, they were using a ‘magic plug cap that did it all’.

[DewCatTea-Bob]

[quote= Harvey ...
" Bob you got me intrigued again. "

____ I'm always content to reveal advanced conceptions for review by those with mere common-knowledge, Harvey. _ (Your inquisitions don't make me squirm TOO awfully much, to make me hesitant.)



" Firstly as he is using a 12V coil on as 12V system, there is no need for a ballast resistor, as it will only reduce the coils output. "

____ Firstly it was due-to his (roughly) doubled dwell-time that I had originally suggested the ballast-resistor for, (so as to help keep Nick's ign.coil from becoming overheated).
__ And nextly, while it's in-fact true that such a resistor will* indeed cut-down the primary-voltage (and-thus also reduce the ign.coil's output-voltage as well),
(* once it's warmed-up),,
unless he happens to have a rather 'cheap' (so-called)- '12v.coil', that expected reduction-loss probably won't make any notable difference, especially after the engine has also become warmed-up...
__ And just because we happen to know that Nick's (yet unspecified) "12V coil" is supposed to be a '12-volt' version, doesn't-really mean that we thus-then automatically know ANYTHING for-sure about it's ACTUAL particular electrical property-specs ! ... Cuz in regards to such ign.coil properties,, general ign.coil specs are so diverse, that 6v & 12v versions certainly can have some overlapping property-specs ! _ And-so in common actuality, there's really no property in particular that can purposely make an ign.coil specifically-be '6'-volt, or '12'-volt, (or "10V"), or ANY specific-voltage in particular, other-than the 'voltage-RATING' that it's manufacturer chose to 'rate' their ign.coil at ! ...
__ IF all ign.coils had to be locked-into a rather narrow/certain-range of internal property-specs, in order to specifically perform their intended-job -(6v or 12v),, THEN of-course your-point would carry substantially more actual-significance. _ However ign.coils in general, actually exploit a rather surprisingly wide range of varied property-specifications which allow them to at-least adequately perform their function...
For instance, their 'primary-resistance' and 'turns-ratio' specs can vary so very-widely between various ign.coils,, that, (CONTRARY to common-presumption**), it's quite-likely possible for some random-example of a so-called 12v.coil to actually have a LOWER primary-resistance and-yet also at the same time, possibly have it's secondary produce a HIGHER*output-voltage, (than that which a common/ordinary so-called 6v.coil happens to exploit), (* even when both versions are fed the very-same voltage-level into their primary-circuits) ! _ (Don't believe it ? _ Then thoroughly check-out a bunch of varied 6 & 12 volt coils, and find-out for your own-self just how rule-less in-general that common ign.coils can possibly be !)
(** Common-reasoning/belief presumes that pretty-much all ign.coils are similarly designed so as to achieve more-or-less the same high-voltage that's required to jump the spark-gap, and-so thus it's assumed that means that the main-difference between 6 & 12 volt versions, is pretty-much merely-just the turns-ratio spec,, and-so it's also commonly-reasoned that a 6v.coil must-have a lower primary-resistance than a 12v.coil, in order to achieve the same sparking-power as the '12v' version.)
Those two main-specs -(primary-resistance & turns-ratio), can possibly vary so widely (between most-all 6 & 12v ign.coil-models), to such a great degree, that their 'voltage-rating' is actually merely little more than a suggested-guide (and certainly-NOT an 'absolute'), within the greater-number of ign.coil-examples,, as their related property-specs can & do well-overlap, regardless of being 'rated' for 6 or 12 volt usage !
__ I've ranted about this common generalization (of 6-or-12) once-before, (over a couple-years back),, protesting that ign.coils really ought-to be rated by another, MORE-useful specification, other-than by just mere 'voltage-ratings', (which has mind-conditioned the general-public into believing that ign.coils are actually voltage-SPECIFIC, when in-fact they're merely-just voltage-rated [as determined by their makers] ). _ As there is NO single/specific-formula that ign.coils need-to exactly comply-with, in order to preform their expected function (as 6v or 12v) !
__ If ya had a large well-varied selection of unfamiliar ign.coils, all of which had their-own perspective factory voltage-rating labels removed,, then exactly-how could ya possibly determine exactly what their original factory voltage-ratings WERE ?
Cuz even with the help of any type of test-meter available, the measured-data would still only allow ya to 'GUESS' whether a tested ign.coil is supposed to-be factory-rated as '6v' or '12v',, as there's no established world-std.formula to determine exactly what any particular ign.coil-producer had actually intended FOR-SURE.
(Of-course this issue wouldn't be such that it is, IF all ign.coils actually had-to meet some particular results,, such-as an established/standardized spark-voltage, or the same-established primary-current, etc. _ But however, ign.coil-manufacturers are-not actually so restricted !)
If ya had a magical ign.coil test-meter (to test that large-batch of unlabeled ign.coils with), and it could somehow definitely tell whether the ign.coil-manufacturer's original-labeling had been either 6v or 12v,, then after using it to segregate all the unlabeled ign.coils into the two groupings (of either factory-labeled 6v or 12v versions), you'd then find that (roughly!) two-thirds of those ign.coils within ONE of the groups, would all share fairly-similar property-specs with each-other, (and of-course would also be notably-different from the equivalent specs of MOST ign.coils segregated into the OTHER-group)... HOWEVER, about one-third within both groups would have property-specs that do-not well correlate with the common property-specs of the majority within the group they were segregated-to, and-so could just-as-well be-at-home in EITHER grouping,, or even (some of THEM) could be considered for further-segregation into a third-grouping, due-to their more-extreme property-spec variances (which seem to-be TOO far-out for being left mixed with either established-group).
So bottom-line is... all 12v.coils are-not created-equal, nor are all 6v.coils created-equal,, and also, their respective sets of property-specs (which supposedly-divide those two groups apart), are too-well SHADED in fairly-deep blurry-murk to-be clearly defined & distinguishable !



" Ballast resistors were used on Auto systems in series with a 10V coil.
The action was that when the starter was used, it pulled the battery voltage down to around 10 to 11 volts, so the coils output was reduced. With the series resistor included, when the starter is running, the resistor is by-passed, so the 10V coil will run on the battery’s reduced voltage, to provide a good spark, when the started is off, the series resistor is again included in the circuit to reduce the 12V down to the coils 10V. "

____ I've heard of that explanation before, and it seems like a mechanic's deductive-reasoning, to me, (rather than an electrical-engineer's). _ Because for one-thing, it's not like the ign.spark can't still do it's intended-job when it's just 17% down on full-HT.voltage, (when a warmed engine is being cranked-over).
I'd be more-apt to accept such conjecture, if I could see the ign.coil with a '10 volt' label affixed.
There's just-not any significant way to differentiate between 12v & 10v ign.coils' internal-construction, to bother with such rather minor specific labeling. _ As such oddly-rated ign.coils would be even more interchangeable than 12v & 6v versions are, and-so may as well also be labeled as 12v.



" The second part is maybe your “tongue in cheek” reference to the TV show that you mention, "

____ I had intended to elaborate on that detail later, but forgot-to,, and later when no-one questioned it, I decided to just let it stand.
__ The plug-cap (on the BSA) was an example of those types that have an internal-gap of their-own which lets it's passing spark light-up the cap's colored-plastic insulator. _ Whilst fairly-neat to see,, the main-function of IT's internal-gap, is to keep a slightly fouled plug from bleeding-down the building-voltage before it can finally muster-up the tension required to jump the plug-gap.
Good for keeping fouled-plugs from misfiring,, but otherwise (with good plugs), not so good for best-ignition,,
(except for the light-show, of-course).



" it would be sheer madness to open the plug gap up to those gaps. It is not needed and will only cause the higher voltage to short out anywhere and everywhere it can, "

____ Why in-heck do you think all of that ?
I thought it was common-knowledge that larger plug-gaps equal easier cold-starting !
And besides, plug-gaps up-to .070" have been common automotive-practice since the '70s !
__ I figured that since Nick has such a strong charging-system, he then may as well employ a stronger automotive-type ign.system, to take better advantage of it. _ Cuz it seems reasonable that anyone who shells-out the heavy-cash for such a powerful charging-system, ought-to reap SOME benefit for their spent-bucks ! _ And other than exceptionally bright head-lighting,, I should think that the easiest eng.starting possible, would naturally also be at the top of the wish-list !


Dukaddy-DUKEs,
Dc.Bob

[Nick]

To clarify, I'm using an aftermarket 12V Lucas coil (whether or not it was made in Lucas-land I have no idea).

I rode it today using the ET points cam and the coil did indeed get hot. Won't ride it again until I install the other AA unit.

[DewCatTea-Bob]

[quote= Nick ...
" I'm using an aftermarket 12V Lucas coil "

____ Not the best-choice, I understand !
__ With your high-output alternator, you could make good use of an automotive-type ign.coil, for a stronger ign.spark.



" I rode it today using the ET points cam and the coil did indeed get hot. "

____ How long did it take to get "hot", and do you mean hot-enough that it was too-hot to keep your fingers pressed-against ? _ (After a 3-mile ride,, I suspect your ign.coil got as 'hot' as the cyl.head, but not as hot as the muffler. _ A coil-casing shouldn't get any warmer than an inlet-manifold does.)


Hopeful-Cheers,
-Bob

[Harvey]

[quote= Harvey ...

" Ballast resistors were used on Auto systems in series with a 10V coil.
The action was that when the starter was used, it pulled the battery voltage down to around 10 to 11 volts, so the coils output was reduced. With the series resistor included, when the starter is running, the resistor is by-passed, so the 10V coil will run on the battery’s reduced voltage, to provide a good spark, when the started is off, the series resistor is again included in the circuit to reduce the 12V down to the coils 10V. "

____ I've heard of that explanation before, and it seems like a mechanic's deductive-reasoning, to me, (rather than an electrical-engineer's). _ Because for one-thing, it's not like the ign.spark can't still do it's intended-job when it's just 17% down on full-HT.voltage, (when a warmed engine is being cranked-over).
I'd be more-apt to accept such conjecture, if I could see the ign.coil with a '10 volt' label affixed.
There's just-not any significant way to differentiate between 12v & 10v ign.coils' internal-construction, to bother with such rather minor specific labeling. _ As such oddly-rated ign.coils would be even more interchangeable than 12v & 6v versions are, and-so may as well also be labeled as 12v.

Well Bob I can only tell you how it is done in the Auto field.

These coils that were to be used with a resistor, usually had “USE WITH A RESISTOR” stamped on the case.
There are several common coils in the Australian Bosch GT coil range.
They had the following specifications.
· GT40: an oil filled conventional type coil, 3 ohm
· GT40R: same as GT40, but 1.5 ohm for use with a ballast resistor of 1.7 ohm
The limiting factor is how much current the ignition points can reliably handle. The coils 1.5 ohm + resistors 1.7 ohm at 12V pulls 3.75 amps, under normal running. When the starter is on the coils 1.5 ohm at 9 V pulls 6 amps. To give reliable starting in cold weather.

" The second part is maybe your “tongue in cheek” reference to the TV show that you mention, "

____ I had intended to elaborate on that detail later, but forgot-to,, and later when no-one questioned it, I decided to just let it stand.
__ The plug-cap (on the BSA) was an example of those types that have an internal-gap of their-own which lets it's passing spark light-up the cap's colored-plastic insulator. _ Whilst fairly-neat to see,, the main-function of IT's internal-gap, is to keep a slightly fouled plug from bleeding-down the building-voltage before it can finally muster-up the tension required to jump the plug-gap.
Good for keeping fouled-plugs from misfiring,, but otherwise (with good plugs), not so good for best-ignition,,
(except for the light-show, of-course).

Yes this use to be common practice in thoes times to clear a fouled plug. Remember some using a coat button with the leads connected in opposite holes, to provide a gap to raise the voltage before the gap.

" it would be sheer madness to open the plug gap up to those gaps. It is not needed and will only cause the higher voltage to short out anywhere and everywhere it can, "

____ Why in-heck do you think all of that ?
I thought it was common-knowledge that larger plug-gaps equal easier cold-starting !
And besides, plug-gaps up-to .070" have been common automotive-practice since the '70s !
__ I figured that since Nick has such a strong charging-system, he then may as well employ a stronger automotive-type ign.system, to take better advantage of it. _ Cuz it seems reasonable that anyone who shells-out the heavy-cash for such a powerful charging-system, ought-to reap SOME benefit for their spent-bucks ! _ And other than exceptionally bright head-lighting,, I should think that the easiest eng.starting possible, would naturally also be at the top of the wish-list !

I think it is a “common misconception” that larger plug gaps are better, just because large gaps have been used in modern cars is no reason for us to copy it.
Since the 70s we have been at the mercy of emission controls, that has detuned the power of our engines. The Auto Industries have had to use very lean mixtures, especially at low rpm and idling, it is because of this that they have to use the gaps that they do.
Contrary to popular belief the spark does not jump the gap. The hi-voltage that the secondary develops across the gap has to ionise the gas to become conductive, so that the current can flow across the gap. With such lean, patchy stratified, mixture in the chamber, the gas is harder to ionise, higher voltages are needed so the gaps are increased so that a higher voltage is developed. There also has to be a higher level of energy to prolong the flow across the gap, as if the spark is too fast, there may not be any combustible gas between the gap, so the spark has to last long enough for some gas to be lit.
This is the problem that Emissions have brought, but we don’t have to run these lean mixtures. We run “old world” mixtures that can be ionised with low voltages of about 20k volts. A plug gap of 25” takes about 12K volts to ionise the gas and only about 2k volts to flow the spark. Using bigger gaps don’t help, and only increase the risk of shorts across the coil or plug cap.
All the old racing plugs that we had from Lodge, KLG. Champion had a preset gap of 18” they were run in blown high compression engines running on Methanol, had no trouble lighting the charge, only had trouble with narrow heat handling properties.

[DewCatTea-Bob]

[quote= Harvey ...
" I think it is a “common misconception” that larger plug gaps are better, just because large gaps have been used in modern cars is no reason for us to copy it.
Since the 70s we have been at the mercy of emission controls, that has detuned the power of our engines. The Auto Industries have had to use very lean mixtures, especially at low rpm and idling, it is because of this that they have to use the gaps that they do. "

____ I pretty-much agree with all that Harvey ! _ However the reasoning for such large spark-gaps being beneficial in our (kick-start !) motorcycle-engines, is-not for those same-reasons, or even for expecting improved power,, but rather for easier COLD-starting ! _ (Which is ALL I had meant to particularly indicate, BEFORE !)



" Contrary to popular belief the spark does not jump the gap. The hi-voltage that the secondary develops across the gap has to ionise the gas to become conductive, so that the current can flow across the gap. "

____ I believe another member here has already reviewed that point, (within the past couple of years).
(Of-course it doesn't hurt to mention that stuff again.)



" With such lean, patchy stratified, mixture in the chamber, the gas is harder to ionise, higher voltages are needed so the gaps are increased so that a higher voltage is developed. There also has to be a higher level of energy to prolong the flow across the gap, as if the spark is too fast, there may not be any combustible gas between the gap, so the spark has to last long enough for some gas to be lit. "

____ And that's ALSO the same kind of reasoning deduced for the beneficial need of larger-gaps for easier cold-starting, as cold-mixtures suffer similar effects as do lean-mixtures !



" We run “old world” mixtures that can be ionised with low voltages of about 20k volts. A plug gap of 25” takes about 12K volts to ionise the gas and only about 2k volts to flow the spark. "

____ I agree that that's probably all quite true,, however, MAINLY-for just the intake-charge of a WARMED-up engine !


" Using bigger gaps don’t help, "

____ I agree that's true, but just for in the case of an engine that's not 'COLD' !
__ I still believe that there's worthy benefit to be reaped from larger plug-gaps, for whenever trying to start a COLD-engine ! _ And the increased-gap ought-not have any downside-effect for running a hot-engine, either.

____ Good-post, thanks Harvey !
__ Hopefully someone with a Duke-single can confirm the results claimed by Cycle-mag about adopting automotive-type ign.systems to achieve easier cold-starting for the L-twins !


Dukaddy-DUKEs,
-Bob

[ecurbruce]

Bob says-
"__ Hopefully someone with a Duke-single can confirm the results claimed by Cycle-mag about adopting automotive-type ign.systems to achieve easier cold-starting for the L-twins ! "

Bob, can you expand any on what Cycle-mag has to say about automotive ignition?

Bruce

[Nick]

Bob - The coil didn't get too hot to touch, but it definitely felt too hot. Anyway, I pulled the frozen up AA unit off the Sebring engine, disassembled and cleaned it and will install it within the next day or two. Hope the coil hasn't been damaged. After riding it about 3 miles, I shut it down, chatted with a friend for about 10 minutes, and then it refused to run, making only intermittent pops. So, pulled the carb apart, looked at plug, etc. Then, it started and ran fine--probably because the coil had cooled (?).

The bike had a fixed point cam with no advance unit, just a cam. The dwell is clearly very different from that of the Sebring unit.

Yes, I know about higher output coils, but for the kind of riding I do the Lucas should be fine.

And yes, I well remember the famous K-Mart coils immortalized in Cycle Magazine! Apparently they were real flame-throwers, and Phil and Cook credited them for much of the bike's astonishing performance.

Is there a particular condenser you could recommend?

nick

[DewCatTea-Bob]

[quote= ecurbruce ...
" can you expand any on what Cycle-mag has to say about automotive ignition? "

____ Well I guess I should've narrowed-down exactly what I was referring-to... While I have a vague memory of some cycle-mag (I think 'Cycle'), referring to replacing the 750-twin's contact-points with automotive sets,, the main-article that Cycle had published, (I believe in two consecutive issues in 1974 or 75), had concerned replacing the stock Ducati ign.coils with any other that would work better. _ So they thoroughly tested a fairly-good number of available ign.coils on the market...
They found that the best-choice which would fit within the stock coil-brackets, were intended for Mercury outboard-motors (and made by Boshe I believe), and while that coil-model was notably better than the stock Ducati-coils, a number of larger-sized ign.coils performed significantly better-yet ! _ And one of them in particular was MUCH-better, and IT was a mere generic automotive-type std.replacement-coil, sold at K-mart, that was among the cheapest, (if not the cheapest of all, price-wise -[I think $6.95] ), of the entire tested group. _ Those at Cycle-mag were understandably amazed that the very BEST-performing ign.coil they tested, was so cheaply-priced as it was ! _ And the term 'K-mart coil' soon became a common-term amongst the Duc.owner-crowd !
__ I went to a couple of local K-mart stores and bought 3 or 4 examples from both locations,, and while they were all the exact-same 12v.model, I had doubts that they were actually identical examples of the very-same coil-model/version that Cycle-mag had found at their chosen K-mart. _ (I still have most of them ! - [As THEY have been kept in my basement,, but my main-stash of used ign.coils, (a couple-dozen), were stolen from my garage].)


Cycle-Cheers,
-Bob

[DewCatTea-Bob]

[quote= Nick ...
" The coil didn't get too hot to touch, but it definitely felt too hot. "

____ Considering the dwell-time it was exposed-to, it indeed should've gotten at-least extra-warm, (but still probably not as hot as a coil gets when the ignition is left-on for 10-min without the engine running) !


" Hope the coil hasn't been damaged. "

____ An ign.coil in normal-condition ought to be able to survive being left-on until the battery has been fully-drained by it, (in such case as the ign.switch had been left-on with the engine stopped). _ So it ought-not have suffered much heat-damage.



" Then, it started and ran fine--probably because the coil had cooled (?). "

____ Or maybe because the engine-itself had cooled-down and was then able to cope with a rich-mixture... What carb.model do you have on your 250-Duke ?
__ I have indeed come-across DUKEs that would run okay until the ign.coil got quite hot *, and would-not run again until the coil cooled-down !
(* The reason for why their ign.coils got overheated, was due-to their-owners trying to run a n-c.type ET/magneto-type ign.system in-combo with w-c.type alternator & AAU. _ [I helped solve their-issue with the use of a power-diode, to cut-down the excessive-current diverted through their ign.coils].)



" The bike had a fixed point cam with no advance unit, just a cam. "

____ I've seen those fixed-cams on old 250Motocross-models but, don't recall ever seeing one in any Mark-III,, you must have an older Mark-III like Jim's. _ (You two ought-to compare your motor-numbers.)
You may find Jim's related thread to be of interest... viewtopic.php?f=3&t=1166&#p7919
__ That you haven't complained about 'kick-back' when trying-to get your engine started-up, (without any AAU),, indicates to-me that either your ign.timing has been fairly retarded, or YOU-sir, are well-familiar with THE starting-procedure for such equipped single-cylinder engines !
__ The 28-degree AAU will make avoiding kick-back, considerably easier for you.



" The dwell is clearly very different from that of the Sebring unit. "

____ Right, the stock dwell is about twice as long as that of the 28-degree AAU. _ So your ign.coil should become spared from passing current so long as it has had to do.



" I know about higher output coils, but for the kind of riding I do the Lucas should be fine. "

____ So then, exactly how were you expecting to ever get your moneys-worth from your EXPENSIVE/modern charging-system ?



" I well remember the famous K-Mart coils immortalized in Cycle Magazine! "

____ Then you must be older than I had assumed.
__ I had an electronic-ign.system & a pair of those K-mart coils all-ready to install on my 750GT, but I never got that job done, (as I waited too-long to come-across suitable mounting-brackets for everything).


" and Phil and Cook credited them for much of the bike's astonishing performance. "

____ I remember their quite-sensible explanation for how an increased plug-gap should improve cold-starting,, and perhaps they're at-least partly responsible for the old-belief that larger-gaps also help general-performance, as well.



" Is there a particular condenser you could recommend? "

____ I know there's an established art for perfectly 'matching' a condenser to whatever particular ign.system-components,, but sorry, I-myself can't recommend a best-choice for your ign.system.


Duke-Cheers,
-Bob