Can electronic ignitions do this?

jseng1 said:
Here's a Harley mag (note the wierd cam lobes). The retard with lever just an eccentric tube that fits over the points arm pivot. Turning the alum arm moves the points arm so its retarded approx 20 deg for starting.

What you want is full advance just off idle RPM. Once the bike is started you may as well have full advance - that's the best option for either a mag or EI. Few EIs can achieve that.
From what I 've heard there are programing limitations with the EIs
Can electronic ignitions do this?
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I don't think there is a non-economic reason why an EI can not be provided with any advance curve you want. I probably agree that economics intrude and designers of EIs keep the advance very simple for that reason.
However, I assume that the optimum spark timing would continue to change with rpm and load. I know it is complicated but do you really think the optimum ignition timing does not change after idle? I interpret you statement as asserting that the timing can be fixed without substantial power loss after idle speeds. However with the speed of flame propagation being fairly constant and constant angular timing giving shorter time for this propagation with increasing rpm, I fail to understand how timing changes could not improve performance. Or am I missing something. I know you know more about engine development than I do but just trying to understand this.
 
Here is a pic of my Joe Hunt magneto front cover after going for a slide down the road when a car cut in front of me and grinded the plug leads down, broke the plug leads as well pics on my plugs after 30k + miles on them, they were still working perfect but reinstalling my old Amals so new plugs to tune them in, the cover now hangs on the door of my spare parts cabinet, my wall of shame lol.

Ashley
Can electronic ignitions do this?
Can electronic ignitions do this?
 
ilikevelos said:
I don't think there is a non-economic reason why an EI can not be provided with any advance curve you want. I probably agree that economics intrude and designers of EIs keep the advance very simple for that reason.
However, I assume that the optimum spark timing would continue to change with rpm and load. I know it is complicated but do you really think the optimum ignition timing does not change after idle? I interpret you statement as asserting that the timing can be fixed without substantial power loss after idle speeds. However with the speed of flame propagation being fairly constant and constant angular timing giving shorter time for this propagation with increasing rpm, I fail to understand how timing changes could not improve performance. Or am I missing something. I know you know more about engine development than I do but just trying to understand this.
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When part of a full EMS then yes. Modern engines run very high CR by our standards, and folk put any old petrol in them. The EMS is largely responsible for this ability as the knock sensors trigger the EMS to make changes to accommodate.

An engine with EMS and EFI and a full set of modern sensors can therefore make very useful use of changing the timing etc.

But our old lumps are different. We really should remember that our engines are basic in the extreme, it’s 77 years old and fed by those horrible carburettor thingies !

I tried a (very expensive) fully programmable ign on a race BSA R3 before and was pretty gutted to find that numerous changes of parameters made sod all difference on the dyno.

I’ve tried playing with ign timing numerous times on the dyno and seldom found any benefit from setting it outside of normal settings.

But my main argument in this context, as already laid out, is the fact that when the ign advance curve of all of the commonly used EIs for Nortons are compared, the actual ign timing at any given RPM varies MASSIVELY. Nevertheless, everyone who uses them says they work perfectly fine. To me that proves that at low RPM, an old Norton pretty much doesn’t care what the timing is within quite a large range.

Having tried fixed ign numerous times, I am convinced that the bikes ran at least as good as with other systems. Although I may well have a different opinion if I were taking the family on holiday in a double adult sidecar, or searching for minimum snatch free speed in top gear!
 
"However, I assume that the optimum spark timing would continue to change with rpm and load. I know it is complicated but do you really think the optimum ignition timing does not change after idle?"

I don't know the physical reason for it but the reality is that after around 3000 RPM, any difference in timing has little/no effect on power in a conventional (non computer-controlled, carbureted) engine. IOW, whatever advance the particular engine "likes" for max advance/power at the peak HP level works for the entire RPM range from that 3000 on up. We did tons of dyno tests involving ignition timing/power and the advance setting that made max power at, say, 7000 RPM, also made the max power at 3000 RPM.
 
Bob Rosenthal is about 70years of age, and is now the Period 3 Historic Champion in the 500cc class - I think he rides Clatworthy's ES2, He says they get the jetting right on the dyno ( I presume with an oxy probe ) then advance the ignition setting withe bike running on the dyno, until they get maximum torque. I always have a problem reconciling horsepower with torque. Torque is twisting power, and horsepower is the ability to do work. It is possible to have a very powerful motor which loses revs very quickly when it is requried to pull hard. The thing which has really stuffed me with the Commando engine has been the strange gearing it needs to really perform, If revs are lost on an up-change with wide ratios, it takes forever to regain them. But with very high gearing and close ratios, the bike is much better. With low overall gearing, the motor seems to be working as hard as it can, but it does the same revs as it does when pulling much higher gearing. With low gearing, it just revs the same as with high gearing, but goes much slower, With lean jetting it is faster, but the same could be achieved by advancing the ignition or raising the compression. The three things are always in balance, and there is an optimum, which the gearing can affect. If you make the motor pull harder, you probably use more throttle, which causes the needles in the carbs to enrich faster, giving less power, That is the reason I use 6D Mikuni needles and feed the throttle on while using very high gearing with close ratios..
 
I have come to believe the 850 Commando engine is at least as good as any other of the same capacity. But I found it to be very different in the ways needed to get it to be quicker. With that sort of gearing, many other bikes would just die in the bum. My mate's Triton 860 is a bit like it, but nowhere near as pronounced. He gets away with using a wide ratio gearbox, but now has a 5 speed Triumph box.
 
@Fast Eddie & @MexicoMike

I agree that once at full advance, there's nothing more to be gained. Basically, Lucas and all (I know of) the EI manufacturers agree with that and have for a VERY long time.

The Lucas AAU we use provides 12 degrees of cam (24 degrees of crank) advance. So for a Norton the kickstart speed advance is 4 degree and for a Triumph is 14 degrees. When I was younger I could kick so hard it was no problem. My old-man wimpy kick would most likely not work and probably hurt me with no advance curve.

Personally, I'm not even going to try a full-advance magneto kick. People love to talk about "fat spark" and show pictures of plugs with .025" gap - hurts my physics/electronics mind - war averted because I'll shut my mouth now!
 
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marshg246 said:
@Fast Eddie & @MexicoMike

I agree that once at full advance, there's nothing more to be gained. Basically, Lucas and all (I know of) the EI manufacturers agree with that and have for a VERY long time.

The Lucas AAU we use provides 12 degrees of cam (24 degrees of chank) advance. So for a Norton the kickstart speed advance is 4 degree and for a Triumph is 14 degrees. When I was younger I could kick so hard it was no problem. My old-man wimpy kick would most likely not work and probably hurt me with no advance curve.

Personally, I'm not even going to try a full-advance magneto kick. People love to talk about "fat spark" and show pictures of plugs with .025" gap - hurts my physics/electronics mind - war averted because I'll shut my mouth now!
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I agree, I would also personally prefer a manual retard for kick starting rather than kick it a full advance, although, as we know, other folk do do this hassle free.

A ran a JH mag last year on a track bike, I had the manual retard lever fitted to that, but it wasn’t needed as that bike was started on rollers and always started INSTANTLY… like BOOM !!

A mate has one on a hot 750 motor with an Alton starter and he starts that without using the retard lever too.
 
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Fast Eddie said:
I agree, I would also personally prefer a manual retard for kick starting rather than kick it a full advance, although, as we know, other folk do do this hassle free.

A ran a JH mag last year on a track bike, I had the manual retar lever fitted to that, but it was t need as that bike was started on rollers and always started INSTANTLY… like BOOM !!

A mate has one on a hot 750 motor with an Alton starter and he staters that without using the retard lever too.
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As I have mentioned before
A mate of mine always uses fixed full advance on his Tritons
 
When the bike is tuned properly, it will usually start easily. I suggest many people do not think logically about tuning. My brother used to race Kawasaki H1 and H2 Kawasaki triple two-stroke engined sidecars which ran methanol . If you get methanol wrong in a two-stroke motor, it will usually not even start. And methanol is usually easier to tune.
I have almost come to blows with him in discussions about tuning carbs. But now he is expert at it, and until he retired, there was never a race he entered, which he did not win. A 750cc two-stroke engine on methanol can be terrifying. He was once in a race which was supposed to be 'historic'. A turbocharged CB750 Honda outfit got in front of him just as the H2 Kawasaki came on song. The Kawasaki jumped about 4 metres into the back of the Honda, It was airborne over my brother and his passenger they had been thrown in front of their bike. Nobody was hurt.

I can remember tuning carbs when I first started racing - I had absolutely no idea. Like a lot of things - it is easy when you know how.
 
baz said:
As I have mentioned before
A mate of mine always uses fixed full advance on his Tritons
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If you bounce a piston off compression in any large British four-stroke engine, you are likely to get bitten. Always kick it over the top without hesitation. Motorcycles are not intentionally mean to people. I always use fixed full advance, then run the bike and discover where the power-band is located in the rev-range, and work with it.
After 5 laps of any race circuit, I have never had a tuning problem.
I don't think my Boyer has an advance curve, and if it does, the curve doesn't do much, which jetting does not fix.
The main thing is always the needle jets.
 
Me: Why doesn't a magneto have a spark advance mechanism?

Someone else: because it doesn't need it!

Me: That doesn't answer the question. Is there some reason that every other kind of ignition has an advance mechanism but many magnetos don't have it??

Someone else: Because it doesn't need it!

Me: So, Can I conclude that not having an advance mechanism is either a flaw that you don't want to talk about, or you actually don't know why many of them don't have an advance.

Someone else: Um,.. it doesn't need it!

Me: So, why do all the other forms of ignition have an advance curve?

Someone else: Because they need it...

Me: Ok, thanks for not answering the question

(BTW, I understand why a race bike wouldn't need one because it doesn't do starts and stops once the race starts, but that's not the case with a road bike)
 
oOnortonoO - the magneto advance unit is shown on the far left. All Dominators, Atlas, pre-unit Triumphs and pre-unit BSAs had this Auto advance which gave full advance just above idle. The alum spacer is for fitting this assembly sprocket to a Commando cam. But other mods are needed to mount a behind the cylinders mag to a Commando. Norton messed up when they deleted the alternative option of rear mounted mag mounts.

Can electronic ignitions do this?



The behind the cylinders mag is $850
Can electronic ignitions do this?
 
o0norton0o said:
Me: Why doesn't a magneto have a spark advance mechanism?

Someone else: because it doesn't need it!

Me: That doesn't answer the question. Is there some reason that every other kind of ignition has an advance mechanism but many magnetos don't have it??

Someone else: Because it doesn't need it!

Me: So, Can I conclude that not having an advance mechanism is either a flaw that you don't want to talk about, or you actually don't know why many of them don't have an advance.

Someone else: Um,.. it doesn't need it!

Me: So, why do all the other forms of ignition have an advance curve?

Someone else: Because they need it...

Me: Ok, thanks for not answering the question

(BTW, I understand why a race bike wouldn't need one because it doesn't do starts and stops once the race starts, but that's not the case with a road bike)
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I’d suggest you’re asking the wrong crowd. We’re all a bunch of laymen here who can only really speak from experience.

My layman’s answer is a collection of some answers already given.

Cost is one, fitting an ATU to a mag would no doubt add some significant cost to what is already an expensive unit. Just the relatively simple retard lever adds $249 !

Cost is also a ‘cost / benefit’ question, and here I’d imagine the manufacturer would say they’ve sold thousands of units and received great praise as to how they perform, which would inevitably raise the question of why add high cost changes to an item that seems to perform perfectly.

So, when a seller says ‘there’s no need’ my interpretation is like the above, he’s sold dozens of units that function perfectly, ergo there is ‘no need’ to add an ATU.

As I said, this is very much a laypersons view based on empirical data.

If you want an ignition system designers view, IMHO you’d have to ask an ignition system designer. But honestly, even then my guess is that they’d all answer the same way “our tests show that our curve is the most optimal” or similar !
 
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Even the wiki page of magneto's doesn't say why magnetos didn't evolve an advance feature to compete with other types of ignitions. That page stated that magneto sparks were weak at low rpm's, and once automobiles adopted more lighting and other electrical systems they required a battery and a charging system for those components anyway, so that electrical system could be used for ignition as well. That was the direction that automotive ignition development followed. The points/condenser mechanisms adopted an advance mechanism for car ignitions, and as I said, The first car my dad learned to drive on, had an advance lever on the steering wheel. You pulled it back to start the car, then advanced it as you went faster, so clearly it was a beneficial feature.

The wiki page didn't say why magnetos didn't become more sophisticated to compete with other forms of ignition... My sense of the benefit of magnetos is how simple they work and that they are seperate from the entire electrical system, so you get home on a dead battery or a wiring dead short every time.

For those who like magnetos, and think I am taking a shit on their preference, I actually see the advantage of having such a simple reliable ignition system not connected to the vehicle's electrical system. I just don't understand why the advance mechanism isn't a more popular feature in them. The only practical reason I could see by just using logic is if they were primarily used for racing where you don't stop and go regularly like road riding, because that's where an advance mechanism would be more beneficial.....

Again, I'm not dissing anyone or magnetos. I just think if they had an advance mechanism as standard, I would think they were more road rider friendly, and I'm surprised that a system with that sort of reliability would stop short on such a simple improvement as an advance mechanism which would make it more competitive as a product....
 
o0norton0o said:
Even the wiki page of magneto's doesn't say why magnetos didn't evolve an advance feature to compete with other types of ignitions. That page stated that magneto sparks were weak at low rpm's, and once automobiles adopted more lighting and other electrical systems they required a battery and a charging system for those components anyway, so that electrical system could be used for ignition as well. That was the direction that automotive ignition development followed. The points/condenser mechanisms adopted an advance mechanism for car ignitions, and as I said, The first car my dad learned to drive on, had an advance lever on the steering wheel. You pulled it back to start the car, then advanced it as you went faster, so clearly it was a beneficial feature.

The wiki page didn't say why magnetos didn't become more sophisticated to compete with other forms of ignition... My sense of the benefit of magnetos is how simple they work and that they are seperate from the entire electrical system, so you get home on a dead battery or a wiring dead short every time.

For those who like magnetos, and think I am taking a shit on their preference, I actually see the advantage of having such a simple reliable ignition system not connected to the vehicle's electrical system. I just don't understand why the advance mechanism isn't a more popular feature in them. The only practical reason I could see by just using logic is if they were primarily used for racing where you don't stop and go regularly like road riding, because that's where an advance mechanism would be more beneficial.....

Again, I'm not dissing anyone or magnetos. I just think if they had an advance mechanism as standard, I would think they were more road rider friendly, and I'm surprised that a system with that sort of reliability would stop short on such a simple improvement as an advance mechanism which would make it more competitive as a product....
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As Jim posted above, the OEM mags back in the day relied on the ATU being in the drive to the mag. There is plenty of space for this in the timing cover, but to include it in the mag design would presumably be more difficult?

I know Lucas mags had their manual advance mechanism built into the mag, that was a relatively simple design whereby the cam ring was moved around manually. I don’t know how other mags do this.

As may have already become clear… I like mags ! As you say, I like the fact they’re totally independent of the rest of the electrical system. They also allow a lower output alternator to work perfectly well. They produce a very good spark. Need no charging. And are very reliable, there is no black box to fail without warning !

Downsides are cost, weight, and they are not as maintenance free as EI as they still have points. And a mag is not as easy to time as a modern EI with built in LED (like Tri Spark).

IMO mags got a reputation for being unreliable in the 70s and 80s when they were running around way beyond their designed life expectancy, and were largely very poorly maintained. They do degrade over time as the shellac coating on the windings breaks down. A nice new EI is always gonna work better than a clapped out old mag !

On a single, or 360 degree twin, I think they’re ideal. On Vincent’s the story was that the mag didn’t have time to fully ‘charge’ between firing cycles of the first and second cylinder, resulting in a weak spark on the second cylinder. I have no idea how factual this really is though.

IMO modern mags, made on modern machinery and containing powerful rare earth magnets are fabulous things for old bikes.
 
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Thanks for responding JIm and Nigel. Thanks for the pictures Jim, I like that the sprocket has the advance mechanism built into it.
 
As I see it and I say modern magnetos as the revs pick up the spark get bigger and better so really wouldn't that be the same as what an advance unit does, but auto advance goes full advance as soon as it gets over idle speed or a little bit above, my Joe Hunt with the 4 rare earth magnets produces a nice big spark even when turning it slowly by hand and because it does why it will fire my Norton quiet easily without retarding it and why most times the kicker only gets 1/2 way through a normal kick the motor will have already fired up and be running before the kicker has done a full swing, some of the older magnetos need a bit more kick/rotation of the crank to fire and a lot of EI needs a bit more rotation of the crank as well before they throw a good spark.
I can't comment on modern EI as I only ran an old Lucas EI and 2 older Boyar EI on my Norton, the Lucas was fitted in1978 having problems with the point and bad AAU unit and the Lucas failed within 11 months of use, it was replaced by the Boyar unit but it failed in 82 a week after the great fire 100 miles from home, but it suffered damage from the fire, so replaced with another Boyar, never had any problem with that Boyar for 30+ years except for a few failed batteries and charging system failed, I always like the magneto set up as my 1981 when I fitted the older JH to it and had no problem with it at all while 9 years on the Triumph with clocking up a lot of miles on it, it had proven to me how good the JH was.
My 850 Featherbed is my hotrod built for lightness, torque and handling so a simple reliable magneto set up was the way I wanted to go, no battery to bother with external coils to bother with, just an independent unit, but being a 850 Commando motor would have been a big job mounting it behind the motor, mounting it straight off the end of the cam is such an easy way to fit with no major moderations as the JH came with the mounting kit, no extra cam chain, no extra AAU unit and no extra sprockets/chain and I don't mind it hang off the side of the timing case hanging in the cool breeze.
Have a magneto mounted behind a hot motor, Jim always says he has no problem with the JH behind the motor but he seems to replace condenser quiet a lot but think its more to do with arcing, the only time I have replaced my condenser is from the lay down 14 years ago after fitting the JH, the replacement condenser is still in the JH to this day and same with the point, I never use a file to clean the point, found out from my JH on the Triumph that if u file the points it takes the hardening off the point and they will wear quicker, I just clean them with white sprit but not very often at all think I have only done that once so far and so far have well over 35k + miles on the JH, would have more miles if my Norton was still an everyday runner as it use to be.
I am no expert when it comes to understanding advance curves everyone seems to talk about all I know is my own Norton and how I built it for my use and the 25 year's experience I have in running Joe Hunt magnetos on 2 British bikes hanging off the timing case without a retard unit fitted, I don't have any problems with one kick to start without retarding without any kick back, I still have my original kick start leg, knee and ankle at 65 years old soon to be 66, but everyone seems to be obsess with retarding a modern JH magneto for easy of starting, well my Norton has easy of starting without a retard unit and I am not trying to convince anyone about the choice of ignitions, I made my choice and where its fitted for myself and after 25 years of having a JH hanging off the side, I might have some idea and the ease of maintaining it where it's mounted, but I have done SFA to maintaining the JH since it's been on my Norton.
It works for me and be too much work involved to mount behind my motor, it's a very simple set up where it is hanging in the breeze and so easy to tune.
By the way I am not a salesman for Joe Hunt magnetos lol, but I am a believer in how good they are, they will never be for everyone but it is for me.

Ashley
 
ashman said:
As I see it and I say modern magnetos as the revs pick up the spark get bigger and better so really wouldn't that be the same as what an advance unit does, but auto advance goes full advance as soon as it gets over idle speed or a little bit above, my Joe Hunt with the 4 rare earth magnets produces a nice big spark even when turning it slowly by hand and because it does why it will fire my Norton quiet easily without retarding it and why most times the kicker only gets 1/2 way through a normal kick the motor will have already fired up and be running before the kicker has done a full swing, some of the older magnetos need a bit more kick/rotation of the crank to fire and a lot of EI needs a bit more rotation of the crank as well before they throw a good spark.
I can't comment on modern EI as I only ran an old Lucas EI and 2 older Boyar EI on my Norton, the Lucas was fitted in1978 having problems with the point and bad AAU unit and the Lucas failed within 11 months of use, it was replaced by the Boyar unit but it failed in 82 a week after the great fire 100 miles from home, but it suffered damage from the fire, so replaced with another Boyar, never had any problem with that Boyar for 30+ years except for a few failed batteries and charging system failed, I always like the magneto set up as my 1981 when I fitted the older JH to it and had no problem with it at all while 9 years on the Triumph with clocking up a lot of miles on it, it had proven to me how good the JH was.
My 850 Featherbed is my hotrod built for lightness, torque and handling so a simple reliable magneto set up was the way I wanted to go, no battery to bother with external coils to bother with, just an independent unit, but being a 850 Commando motor would have been a big job mounting it behind the motor, mounting it straight off the end of the cam is such an easy way to fit with no major moderations as the JH came with the mounting kit, no extra cam chain, no extra AAU unit and no extra sprockets/chain and I don't mind it hang off the side of the timing case hanging in the cool breeze.
Have a magneto mounted behind a hot motor, Jim always says he has no problem with the JH behind the motor but he seems to replace condenser quiet a lot but think its more to do with arcing, the only time I have replaced my condenser is from the lay down 14 years ago after fitting the JH, the replacement condenser is still in the JH to this day and same with the point, I never use a file to clean the point, found out from my JH on the Triumph that if u file the points it takes the hardening off the point and they will wear quicker, I just clean them with white sprit but not very often at all think I have only done that once so far and so far have well over 35k + miles on the JH, would have more miles if my Norton was still an everyday runner as it use to be.
I am no expert when it comes to understanding advance curves everyone seems to talk about all I know is my own Norton and how I built it for my use and the 25 year's experience I have in running Joe Hunt magnetos on 2 British bikes hanging off the timing case without a retard unit fitted, I don't have any problems with one kick to start without retarding without any kick back, I still have my original kick start leg, knee and ankle at 65 years old soon to be 66, but everyone seems to be obsess with retarding a modern JH magneto for easy of starting, well my Norton has easy of starting without a retard unit and I am not trying to convince anyone about the choice of ignitions, I made my choice and where its fitted for myself and after 25 years of having a JH hanging off the side, I might have some idea and the ease of maintaining it where it's mounted, but I have done SFA to maintaining the JH since it's been on my Norton.
It works for me and be too much work involved to mount behind my motor, it's a very simple set up where it is hanging in the breeze and so easy to tune.
By the way I am not a salesman for Joe Hunt magnetos lol, but I am a believer in how good they are, they will never be for everyone but it is for me.

Ashley
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How about this. Write down this post number, put it in an envelope, write on the envelope "Open on my 75th birthday". When that time comes around, open it and report back. Maybe you'll be lucky, still be alive, still have all your natural parts, have no arthritis, still have a super powerful kickstart leg, and so on. More likely...

BTW, I used to be able to start BSA B50MX without using the compression release and with Energy Transfer ignition. I'm positive something would break if I tried that today. No kickback when kicking at full advance simply means that you are strong enough to kick hard enough to overcome the kickback that absolutely will happen if the engine fires before TDC and not turning fast enough to get there with the flame front advancing!
 
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