Author Topic: Dyna ''S'' Ignition - what coils are best/correct ?  (Read 30177 times)

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Offline armour

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Dyna ''S'' Ignition - what coils are best/correct ?
« on: February 26, 2011, 09:18:21 AM »
Yes I used the search button .
So can someone definately answer this question ?
I have the Dyna 3 ohm green coils ready to go in a 1977 CB400F , with the Dyna ignition already installed years ago.
There seems to be a combo of opinions , 3 ohm coils are good AND 5 ohm coils are good. Which one set is best ?
 ???

Offline Gordon

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #1 on: February 26, 2011, 12:21:33 PM »
There is no definitive answer, which is probably why you couldn't find one.  "Which is best" is a matter of personal opinion combined with what you want from a set of coils and what you're willing to give up in the trade-off. 

Search "3ohm" and "5ohm" and "dyna coil", read other's experiences with varying combinations on a variety of bikes, and then make the decision that best suits what you want. 

Offline TwoTired

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #2 on: February 26, 2011, 12:34:00 PM »
For your charging system -- 5ohm.
Lloyd... (SOHC4 #11 Original Mail List)
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Offline solo 2

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #3 on: February 26, 2011, 03:46:24 PM »
The 3ohm coils were made for the Dyna S ignition and bikes with electronic ignitions of that resistance. Spark wise there is no difference between the two. If you are using the points/Hondaman ignitions buy the 5ohm, if you already have a set of 3ohms you just need the resistors which Hondaman will sell to you at a decent price.
« Last Edit: February 26, 2011, 03:49:40 PM by solo 2 »
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Offline JScottB

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #4 on: February 26, 2011, 09:03:27 PM »
Even Dyna doesn't recommend their 3 ohm coils for everyday street use because it puts a drain on the charging system originally equipped with a points ignition and 5 ohm coils. Yeah you can put resistors in with the 3 ohm coils to combat this but that destroys the whole purpose of spending that kind of money on the "high output" coils because once you have installed resistors to increase it's ohm resistance so it won't tax your charging system, you end up with a coil that doesn't put out anymore than a stock coil.
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Offline jaguar

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #5 on: February 26, 2011, 09:24:21 PM »
i was told to use the 2.2ohm coils with a dyna 2000
i have resistors too.

i dont quite understand the difference between a 5ohm coil and a 3ohm coil with a 2 ohm resistor.  one must be better then the other

Offline sebatje

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #6 on: February 26, 2011, 10:49:40 PM »
4 months ago I met a guy from Dyna at the motorcycle fair Intermot. He recomended to use the 3 Ohm coils with the Dyna S for a daily drive and the 5 Ohm coils for racing applications...

Offline Roach

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #7 on: February 26, 2011, 11:12:53 PM »
4 months ago I met a guy from Dyna at the motorcycle fair Intermot. He recomended to use the 3 Ohm coils with the Dyna S for a daily drive and the 5 Ohm coils for racing applications...

that seems oposite to be

i know with my 550 the 3ohm coils and dyna s = dead battery all the time my charging system cant handle it. but 5ohm and dyna s is fine
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Offline Duke McDukiedook

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #8 on: February 26, 2011, 11:16:48 PM »
For your charging system -- 5ohm.
Yes, for your application go with 5 ohm or if you already have 3 ohm coils, put resistors on them.
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Offline Gordon

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #9 on: February 27, 2011, 01:50:12 AM »
See what I mean, Armour?  Isn't it all so clear now? ;)

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #10 on: February 27, 2011, 03:50:24 AM »
** It has been pointed out I was a little HARSH in my original wording**

I have a poll on the forum that indicates some interesting comments on points vs Dyna and other Solid State ignition systems.

I have found Dyna does not seem to be able to operate the units at the temperatures the units operate in when applied to the CB750.  My unit developed a 2/3 piston drop out once the motor was hot. They could not duplicate my intermittent problem and their response was less then i believe I had the right to expect.

In the end they gave me my money back because I am a demanding SOB.  The payment is a nice thing, but I would have preferred the unit repaired tested, and returned.

http://forums.sohc4.net/index.php?topic=76709.0

Mark

** Gordon, Ofreen, Terry, and Retro is this wording better?

« Last Edit: February 28, 2011, 03:48:06 PM by Markcb750 »

Offline JScottB

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #11 on: February 27, 2011, 06:22:26 AM »
The question I have is is there upgrades that can be done to stock stators and rectifiers on older bikes that originally came with points ignition and 5 ohm coils so they can properly handle an electronic ignition upgrade without having to use resistors with 3 ohm coils? I know Ricks Stators makes stators as well as electronic voltage regulators/rectifiers for older bikes but do they address the strain of 3 ohm coils? I have a new stator and electronic voltage regulator from Ricks Stators on my 71 cb350 and have had no charging issues at all since I installed it but it still has factory coils and points ign.
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Offline Gordon

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #12 on: February 27, 2011, 07:10:14 AM »
Dyna has a significant failure rate on the Dyna S units. I have a poll on the forum that indicates a failure rate several times that of stock points and  other ignition systems.


Sorry, but that poll can in no way be considered scientific or statistically accurate. 

Offline armour

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #13 on: February 27, 2011, 07:40:15 AM »
See what I mean, Armour?  Isn't it all so clear now? ;)

^ As mud ! Electricals are not my strong suit . Now I'm dizzy ( no pun ) .
Then I'll ask : What IS the best system that eliminates points and gives a nice spark,
without risk of smoking wires etc ? 1977 CB400F , stock cam / pistons .  ???

Offline Gordon

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #14 on: February 27, 2011, 08:11:42 AM »
See what I mean, Armour?  Isn't it all so clear now? ;)

^ As mud ! Electricals are not my strong suit . Now I'm dizzy ( no pun ) .
Then I'll ask : What IS the best system that eliminates points and gives a nice spark,
without risk of smoking wires etc ? 1977 CB400F , stock cam / pistons .  ???

Might as well ask "which oil is best?" ;D

I'll quote my first post:

There is no definitive answer, which is probably why you couldn't find one.  "Which is best" is a matter of personal opinion combined with what you want from a set of coils and what you're willing to give up in the trade-off. 

Just replace "set of coils" in that post with "electronic ignition". 

You're not going to get a definitive answer to questions like this.  Use the search function to find discussions on these kinds of topics, find out what other's experiences with different products on different bikes were, and make your own decision for your own application.  You'll get plenty of opinions, anecdotes, and sometimes even technical info (that you then have to determine the legitimacy of for yourself) by re-asking questions that have been asked dozens of times before, but you'll find the same information, and then some, by doing a search.



p.s.  Please don't actually ask "which oil is best?". :o

Offline Eydugstr

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #15 on: February 27, 2011, 09:34:04 AM »
Yes I used the search button .
So can someone definately answer this question ?
I have the Dyna 3 ohm green coils ready to go in a 1977 CB400F , with the Dyna ignition already installed years ago.
There seems to be a combo of opinions , 3 ohm coils are good AND 5 ohm coils are good. Which one set is best ?
 ???
You're not going to get a definitive answer to questions like this.  Use the search function to find discussions on these kinds of topics, find out what other's experiences with different products on different bikes were, and make your own decision for your own application.  You'll get plenty of opinions, anecdotes, and sometimes even technical info (that you then have to determine the legitimacy of for yourself) by re-asking questions that have been asked dozens of times before, but you'll find the same information, and then some, by doing a search.



p.s.  Please don't actually ask "which oil is best?". :o

Armour - Please don't let the answers discourage you;  These guys are just telling it like it they see it.  Not too long ago I searched the forum and didn't come up with a conclusive answer, so I asked the same question...and (shouldn't have been surprised) got pretty much the same varied responses.

But this is what I took from it...It's one of those situations where everyone rides differently (some take long trips, some race, some just ride around town, etc), the bikes are in different states of repair, so the results are different.  That's why some guys had no problems at all running a stock 3 ohm coil with their Dyna S and others fried their switches!!  I just got back from a local shop, and talked to a guy who runs a Dyna S on his CB400f with stock coils;  He said it ran well but always needed to be on the battery charger.

What I'd recommend to do is this;  Contact Hondaman (forum member) about some resistors for your 3 ohm dyna coils, and definitely clean up all the electrical connectors & switches, run the bike, and go from there.

Offline Kong

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #16 on: February 27, 2011, 10:09:32 AM »
The concept is simple - Ohms equal resistance.  If you use 3 Ohm coils then in comparison to 5 Ohm coils more power comes into them and as a consequence more power comes out of them.  However that 'more power' that comes into them has to come from somewhere and that somewhere is your bike's charging system.  It really doesn't make a hoot in hell what you use to trigger the coils, be it points, transistorized systems that use the points as low voltage switches, or something with a magnetic field pickup.

I have a 550 I'm building and what I did was look up the rated output of the alternator.  I was surprised to find out two things about it, first that it put out full power by 2,000 RPM, and second that it only put out slightly over 10.5 amp hours of power at maximum.  So once I knew that I just went around the bike and added up all the power draws and thought about what might be working while riding and came to the conclusion that under no circumstance could the charging system keep up using 3-Ohm coils.  The bike was about a quarter to a half of an amp short no matter how I jiggled the numbers.

So all I can say is that you've got a set of 3-Ohm coils working OK in a stock 550 then you've got an alternator that is producing at least a little more power than the specifications indicate and also that you have just about perfectly clean connections everywhere in your electrical system.  Good for you.  The rest of us hover right on the brink and i figured rather than fall over the edge I'd just revert to 5-Ohm coils and have that little bit of spare power in my electrical system.  Your results may vary.
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Offline TwoTired

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #17 on: February 27, 2011, 01:01:36 PM »
The answer IS definitive, IF you care to pay attention to physics and math.
The points draw power through the coils during 195 degrees of crankshaft rotation.
195/360 (degrees of rotation) = .54 or 54% coil on time for EACH coil/points set.

The DC resistance of ONE coil primary and the voltage applied to it determines the current/power draw of the coil.
12.6V / 5 ohms = 2.52 amps.  And 2.52 amps x 12.6V = 31.72 Watts  There are TWO coils for a maximum consumption of 63.504 Watts.  However, the points only allow each coil to be on during 54% of crank rotation. 
So, 54% of 63.504 watts = 34.29 Watts power consumption. (<-- STOCK IGNITION SYSTEM)


The Dyna-S dwell time (coil ON time) is 315 degrees of crank rotation (using Hondaman's ignition analysis).
315/360 (degrees of rotation) = 0.876 or 88% coil on time for EACH trigger switch.

Still using 5 ohm coils, the power draw increases just because they are on for a longer duration of time.
There are 2 coils driven by the battery.  While the coils draw the same power as with points when they are closed, the current power draw time for the electronic switch is increased from 34.29 Watts to 55.88 watts power consumption, just by using the Dyna-S.

Now add 3 ohm coils And the Dyna-S
12.6V / 3 ohms = 4.2 amps.  And 4.2 amps x 12.6V = 52.92 Watts  There are TWO coils for a maximum consumption of 105.84 Watts.  The Dyna-S allows each coil to be on during 88% of crank rotation. 
So, 88% of 105.84 watts = 93.14 Watts power consumption. (<-- DYNA-S and 3 ohm coils)

So, the "high performance" changeover sucks far more than double the power as the stock system. (more about this later)

Can YOUR charging system still keep up the normal bike loads AND an increase of consumed power?  This depends on your model bike and how you ride it.
You want your lights on?  Then most of the SOHC4s with stock ignition draw about 10-11 amps, when lights and key switch are on.  That's about 120-140 Watts.
The alternator's outputs vary by model and the RPM they are spun at.  The 400, for example, is rated at 156 watts @ 5000 RPM.  Note that idle RPM is about 1/3 of maximum output.  If you add an additional 60 watt ignition system load to the normal stock load you will have a 180-200 watt load on a system capable restoring 156 watts max.  You better hope that your alternator was made to perform better than minimum performance specs at the factory AND that you will never run the engine below 5000 RPM, or your battery will run flat in under an hour, and you have a wonderful push toy.

But, what does the "high performance" ignition system do for you in exchange for short battery life?
The spark plugs fire with energy stored in the coils when the points/ electronic switch while is turned off.  This allows the energy field created by the coils to collapse. The collapse continues until there is enough voltage the create a low resistance plasma channel between the gap electrodes. This is when current flows through the system and spark occurs.  Notice that while there must be enough energy in the coil for this to occur, that actual voltage need for the event is determined by the spark gap (the gaseous conditions between the gap), NOT the coil max capability.   This means that peak potential voltage that the coil is capable of producing does NOT translate to higher spark voltage.  This is only what salesmen and "believers" want you to assume in order to separate money from you wallet.  ALL the testimonials from "believers and "marks" that have bought the lie mean nothing in the real world of true physical behavior.

When do you "NEED" higher spark potential?
1 - Change the plasma channel conditions between the spark electrodes.  Higher pressures require higher voltage to create the channel (I.E higher compression ratio.)
2- Increase the spark GAP between the electrodes.  A larger gap require more voltage to form the plasma channel.
3- extend the useful life of spark plugs.  As spark electrodes wear, they actually need higher voltages to form the plasma channel.

But, does the extra power of the system add to rear wheel HP on the road?   No, this is preposterous.  Even if you did add 60 watts consumption to the ignition system and delivered it to the combustion chamber.  60 watts = 0.080461325 HP.  And remember half is that total increase in power consumption is wasted, sparking between exhaust and intake stroke.  It CAN be logically argued that other engine changes that (in turn) require higher spark voltages will increase the rear wheel power.  But, ignition power alone does not not, can not.

The Dyna-S does provide a consistency of spark (timing and duration), that the points trigger system can't maintain during extended use.  This is due to the high currents during make and break of the point contacts, causing overheating and distorting the contacts themselves.  These effects are cumulative.  Devices that reduce the current flowing through the points greatly extends their stability and reliability.  It is too bad the Dyna-S doesn't mimic the stock points dwell/ points cam time durations.  If it did, it would be a total win and worth more of the inflated price they ask for a short sighted design. IMO

For street use conditions 5 ohm coils are most appropriate.
For modified engines, racing applications, 3 ohm coils may be a better choice (other factors to be considered), IF your charging system is up to the task or you don't have far to push the bike back to an external battery charger.

Maybe someone will actually read this?

Cheers,
 
Lloyd... (SOHC4 #11 Original Mail List)
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Offline armour

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #18 on: February 27, 2011, 02:23:06 PM »
Thanks for an excellent response which will no doubt help others besides me !
So really, 5 ohm coils are the way......this change from the existing stock coils will enhance the ''no points'' dyna ''s'' ?
Is there another , ''everybody wins'' system that can be recommended , besides the dyna ''s'' specifically - suitable for
regular street driving a few times a month ( headlight mandatory ) ? Can you also then mention the right plugs/wires/boots setup ?  :)

Offline Terry in Australia

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #19 on: February 27, 2011, 02:40:51 PM »
I've run Dyna "S" and (now discontinued, sadly) Dyna III and Martek ignitions in CB750's for the last 30 years or so, with absolutely no problems at all. Dyna states in their installation instructions that the minimum requirement for the Dyna S is 3 Ohms, but their 5 Ohm coils (or for that matter, stock Honda 5 Ohm coils in really good condition) work fine with the "S".

Of course, here in Oz we didn't have the mandatory "Lights on all the time" laws that you had in the US, (yes, we did get it 20 years later, but it's since been repealed) so that might be why I've never had a flat battery as a result of installing an electronic ignition, regardless of whether I was riding long distances, or just commuting to work.

Cost wise, a Dyna S and Dyna coils is no more expensive that OEM, and considering that there are plenty of bikes out there with 10 year old (plus) electronic ignitions, are just as good value, or better, than OEM. Cheers, Terry. ;D
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Offline Killer Canary

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #20 on: February 27, 2011, 02:58:42 PM »
You guys managed to get a law repealed? We've had the daylight lighting laws since the mid 70s but I've had the impression that the U.S. still doesn't.I have CB350 twin and Kawi triple that were imported before the law came into effect and I intentionally switch the lights off during the day to ease the load on the alt. Even though I haven't had an alternator problem in 36 yrs. of riding. If a law actually saves lives it's a good thing then.
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Offline ofreen

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #21 on: February 27, 2011, 03:23:08 PM »
Of course, here in Oz we didn't have the mandatory "Lights on all the time" laws that you had in the US, (yes, we did get it 20 years later, but it's since been repealed) so that might be why I've never had a flat battery as a result of installing an electronic ignition, regardless of whether I was riding long distances, or just commuting to work.

The only way you can turn the headlight off on my '75 750F is unplug it, so it is on all the time.  I've never had charging issues and batteries have always lasted 7 years or more.  The Westco AGM battery currently in the 750 was put into service in my CBR in late 2001.  I moved it to the 750 in 2008 and it is still going strong.  I read all the negative stuff written on this forum about Dyna ignitions and just shake my head.  It usually falls to you or I to balance the negative.  I can't speak for the smaller bikes, but the Dyna S and 3 ohm coils work fine in the 750.  The set in mine is going on 20 years and over 90,000 miles now.
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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #22 on: February 27, 2011, 03:31:58 PM »

The only way you can turn the headlight off on my '75 750F is unplug it, so it is on all the time.  I've never had charging issues and batteries have always lasted 7 years or more.  The Westco AGM battery currently in the 750 was put into service in my CBR in late 2001.  I moved it to the 750 in 2008 and it is still going strong.  I read all the negative stuff written on this forum about Dyna ignitions and just shake my head.  It usually falls to you or I to balance the negative.  I can't speak for the smaller bikes, but the Dyna S and 3 ohm coils work fine in the 750.  The set in mine is going on 20 years and over 90,000 miles now.


That is what I expected, I was disappointed in the failure I experienced, even more disappointed in Dyna's lack of commitment to finding and fixing the problem.  Or simply selling me a pickup unit so I could fix it myself.

Offline Terry in Australia

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #23 on: February 27, 2011, 03:51:33 PM »
You guys managed to get a law repealed? We've had the daylight lighting laws since the mid 70s but I've had the impression that the U.S. still doesn't.I have CB350 twin and Kawi triple that were imported before the law came into effect and I intentionally switch the lights off during the day to ease the load on the alt. Even though I haven't had an alternator problem in 36 yrs. of riding. If a law actually saves lives it's a good thing then.

Yeah mate, there were all sorts of legal arguments for, and against daylight "lights on" laws, which ultimately ended in the lights on law's demise. I personally think that if your charging system can handle it, it's better to err on the side of caution and run lights whenever you can, but my poor old BMW R100RS (with points ignition) had such a weak charging system that I had to switch my lights off or I would have spent more time pushing it, than riding, which probably would have lead to other safety issues, pushing a 500 pound bike at 3 MPH on a freeway isn't conducive to longevity! ;D
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Offline Killer Canary

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Re: Dyna ''S'' Ignition - what coils are best/correct ?
« Reply #24 on: February 27, 2011, 03:54:06 PM »
I guess not! Sorry for the digression everyone.
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