On using GM HEI ignition modules

[DewCatTea-Bob]

" I agree with you that the actual shape of the curve doesn't matter much. I think that's what you're saying? "

____ Yes, that's the 'bottom-line' alright Jordan ! _ I had tried my best and assumed that all my wording had made that about as clear as possible but, I do realize that my sentences often run too long for the intended thought (of a sentence) to be followed-through (clearly),, so I regularly require use of these: ( ) a lot, so as to include extra-wording that really doesn't need to be read in order for the point of the sentence to be understood. _ As it's my understanding that everyone is supposed to know that -(that these extra words within (), are merely expected to help keep the reader to stay on track with the intended train of thought).


" High Energy Ignition (HEI) is an enhanced performance ignition. The term is given to a type that uses dwell-extension by electronic control. It makes the dwell (the time the ignition coil has to charge) independent of engine speed, and has a variable mark-space ratio. That's supposed to help keep ignition power up at high revs, which otherwise would have progressively shorter time to charge the coil. "

____ Well-put Jordan, and details that should've been covered sooner within this thread (covering the HEI).
__ I had already read about that detailed info (provided by a link*) within another thread (over a half-year back). _ (* I think the link was in a thread titled: "Points or Electronic-Ignition".) _ A search containing "HEI" may turn-up the other (older) posts concerning this interesting topic.


" but it's not something I need for my bike, and requires a battery I think. I'm gonna ditch the battery, as it's not needed with self-generating CDI ignitions like on Ducatis. "

____ Still, (while also providing those extra functions you don't really need), I believe the HEI-module would still work (along with your current trigger-system) to fire just about any ign.coil you choose.
__ And while the module's circuits no-doubt do require a steady DC-source, it probably doesn't consume very much current-supply and thus could possibly be powered by a 6-volt dry-cell lantern-battery (or maybe even just a little 9-volt), if so chosen (instead of a regular bike-battery).
____ So is it your hope to make use of a battery-eliminator circuit of some kind, and also convert to a 12volt-system as well ?


Hopeful-Cheers,
-Bob


____ Follow-Up! .....
I've now completed a successful search and found the post (by Pete) containing the link which I was referring to...
The containing thread titled: "Points or Electronic Ignition?" is (currently!) found nearly half-way down on page-6 (and may still contain info of interest to you).
But rather than leave that fairly important link to be found only in that (less HEI related) thread, I'm copying that link (which Pete was so resourceful to provide for us!), to be found here now, as well ! ...
http://www.mynode.com/2wheel/?t=simple. ... index.html
__ It's a bit more relevant than any link provided (thus far) within this thread cuz it refers to the HEI-module being installed on an actual Duke (instead of just some Jap-bike -[like the 400-Kaw] ), and since the link's related write-up is rather old -(2006), that web.page may not be found (at the other-end of this provided link) for very much longer. _ So be sure to check-it-out ASAP !

[Jordan]

____ So is it your hope to make use of a battery-eliminator circuit of some kind, and also convert to a 12volt-system as well ?

There are 2 ways to go on this I think. Either use a rectified, regulated, storage capacitor system (battery eliminator), or keep it simple and use a "balanced system", which matches load to maximum power output of the alternator, and feeds AC directly to the loads. Because of the type of bike I'm pretending it is - a balls-out, no-nonsense pukka cafe racer - I might go for the minimal method. It's practical except if you want to have direction indicators. I don't see much advantage in going from 6V to 12V, as long as I can buy the bulbs I need. The coils on the Motoplat alternator are encased in moulded plastic anyway, so it's not an easy thing to get at to rewire.


http://www.mynode.com/2wheel/?t=simple. ... index.html

This article mentions something I wasn't aware of - the ability to reduce current demand at low revs (as well as increasing it when it's needed at high revs).
That's gotta be a good thing. But I'm aiming to go batteryless for this project.

To mention something else, the Dyna-S ignition system is neat in that it doesn't use a separate "black box". You just connect the pickup directly to the coils, all the electronics are in the pickup unit. I recently found out that, although it needs 12V DC power, it happily starts an engine using a battery eliminator.

Jordan

[DewCatTea-Bob]

" and feeds AC directly to the loads. "

____ I gather that many (more modern) Jap-dirtbikes use such an electrical-system...
It only requires a 'dual Zener-circuit module' which does for AC about the same as what a common voltage-regulator unit does for a common DC-system.


" The coils on the Motoplat alternator are encased in moulded plastic anyway, so it's not an easy thing to get at to rewire. "

____ So what makes you think that any w-c alternator needs to be rewired (for what purpose)?


" the Dyna-S ignition system is neat in that it doesn't use a separate "black box".
all the electronics are in the pickup unit. "

____ That's one of the "pick-ups" I had in mind when I previously mentioned that a 'pick-up' can contain more "electronics" than just a simple sensor !


Dukaddy-DUKEs,
-Bob

[Jordan]

[quote="DewCatTea-Bob"]

____ So what makes you think that any w-c alternator needs to be rewired (for what purpose)?

For higher voltage at low revs than would otherwise be the case. We know your view is that it's not needed and maybe it isn't. I don't have much evidence that it is, except that Ducati reportedly made a 12V alternator for singles.

Jordan

[DewCatTea-Bob]

" For higher voltage at low revs than would otherwise be the case. "

____ Well Jordan, either you haven't read the (correct) thread concerning the wide-case alternator charging-system or didn't understand it correctly, or more likely also read another thread (about another alt.system set-up) and have since gotten them -(the details of separate posts) confused in your memory, (or something of the sort),, cuz the w-c alt.circuits are not grounded (internally to the stator) and are already wired as is needed for most any charging-system (6 OR 12v) to be connected ! _ Thus there's no good reason to bother with modifying a w-c alt.stator, (unless the existing/stock 3 wire-leads need to be replaced anyhow) !
__ The stock 6v-system (on w-c singles) ONLY makes use of just ONE-HALF of the total-voltage (AND also 1/2 of total-current) that's available from the STOCK-alternator !! ...
Thus there would be no need for Ducati to have ever bothered with producing another alternator (for their w-c singles) that's any different (than those made since 1968, [for just the charging-system] ) !


" except that Ducati reportedly made a 12V alternator for singles. "

____ At this moment I don't really recall ever hearing of (exactly) that before... Are you sure that it wasn't simply the 'regulator-box' (rather than the alternator) that was actually responsible for the ('reported') Duc.factory 12v-system for their singles ?
__ Some of those who know me have been advised that to most simply obtain a 12-volt (all Ducati) charging-system for their w-c Duke (which is also intended to retain the stock load-wattage of a single), merely need to simply replace the stock 6-volt reg.box-unit with a 12-volt version (made for a pre-1976 L-twin).
____ So I'm wondering where you heard-of "a 12V alternator for singles" ?? - (I think it's just a misunderstanding [somewhere along the trail of the tail].)


Dukaddy-DUKEs,
-Bob

[Pete]

" except that Ducati reportedly made a 12V alternator for singles. "

____ At this moment I don't really recall ever hearing of (exactly) that before... Are you sure that it wasn't simply the 'regulator-box' (rather than the alternator) that was actually responsible for the ('reported') Duc.factory 12v-system for their singles ?
__ Some of those who know me have been advised that to most simply obtain a 12-volt (all Ducati) charging-system for their w-c Duke (which is also intended to retain the stock load-wattage of a single), they simply need replace the stock 6-volt reg.box-unit with a 12-volt version (made for a pre-1976 L-twin).
____ So I'm wondering where you heard-of "a 12V alternator for singles" ?? - (I think it's just a misunderstanding [somewhere along the trail of the tail].)


Dukaddy-DUKEs,
-Bob

According to Mick Walker, Mototrans produced a widecase style 250 in 1978 with 12v electrics ( Motoplat ). Maybe some one who is familiar with these cycles, called Stradas can inform us about the components used to get the 12v.

Pete

[DewCatTea-Bob]

" Mototrans produced a widecase style 250 in 1978 with 12v electrics ( Motoplat ). "

____ Thanks much for your informative input Pete !
__ It makes fair sense to me that the source of any such report/tail (about a Duc.factory-made 12v-alternator produced for stock Duc.singles), would have it's roots based on SPANISH-made/Mototrans-DUCATIs, of which I'd have very little knowledge of (since most Mototrans productions were never imported into the U.S.A. [where I've always resided]).


Dukaddy-DUKEs,
-Bob

[Jon Pegler]

Mototrans produced a number of different alternators that would give 12 volts by simply wiring up a 12 volt regulator.
These were made in both widecase and narrowcase format. (Either 3 screw fixing for narrowcase or 4 screw fixing for widecase)
Some were fully encapsulated in plastic resin and some had exposed coils.
The narrowcase ones were fitted to some of their later machines, certainly the 24 Horas and Elite V5 and possibly some of the Road models. These usually have a six magnet aluminium rotor.
The widecase alternators fitted to the Strada, Forza and Vento models also come with both the plastic encapsulated or exposed coils but have different flywheels.
These flywheels require a different extractor to remove them. It uses a 33x1mm MALE thread, unlike the more usual 55x1 or 62x1 FEMALE threaded extractor.
Just to confuse the issue, there are also widecase Motoplat flywheels that use a 62x1.25 thread on the extractor.
The early Forza flywheels also have a ring gear for the electric starter fitted. These are built up flywheels like the parallel twin Ducatis, with magnets cast into an aluminium ring and a seperate centre and ring gear.
If I could suss out how to post a few photos, I could show pictures of some of these Motoplat alternator variations as I have probably got examples of all of them.

Jon

[Jordan]

Hey Jon, more info needed.
Have you changed a Ducati or Mototrans alternator from 6V to 12V system? How did it go? What style of riding - low speed commuting in all conditions, or high speed in daytime only?
Do you know what voltage the electric start single was?

Jordan

[Jon Pegler]

Jordan

I run all my Ducati singles with 12 volt electrical systems.
I'm based in the UK, which is often dark and wet, so good lights are important.
All of my machines get ridden hard, but only occasionally now. No commuting anymore.
I've got Ducati, Motoplat and Electrex generators fitted to different machines, running through various different regulator units. Not necessarily the most economical way to go, but at least the lights all work.
The Spanish electric start singles are all 12 volt as standard.
The early Forzas with the electric start at the front of the crankcase were not very successful. The ring gear taking the drive from the starter motor to the crankshaft is on the flywheel. As the flywheel is only held on a taper and not keyed, they have a habit of coming loose and chewing up the crank.
The later Forzas have a starter mounted above the gearbox, behind the cylinder barrel (jug). This drove the crankshaft using a chain and a sprag clutch, much like the bevel V-twins. This is a much better arrangement. Unfortunately, Mototrans only made them for a couple of years.
I've got one of each type of Forza and would say that the later one is the better thought out. The early one used too many parts from the parallel twin parts bin.
Maybe we're getting a bit off topic now and should post this in the Mototrans section.

Jon