Topic: Dynatek leads and stock plug caps

[Gordo]

Hi guys dumb question time. Fitting  5 ohm dynatek coils and dynatek leads which have plug caps pre formed, any need to cut pre formed caps off and fit ngk 5 ohm caps?
Cheers gordon
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[madmtnmotors]

I have never used stock (NGK) plug caps with Dyna wires.

[Jerry Rxman Griffin aka MuthaF'er]

No. Dyna knows what they are doing. Plus why spend more on new NGK caps then thusly reduce the voltage.

[Gordo]

Cheers for the replies just wanted to check as I have spare plug caps if I needed to fit them for any reason.

[Deltarider]

But you need resistors, either in the caps or in the plugs ("R"), so check if your Dynatek leads/caps have built in resistors. Back then mine didn't, so you'd better check.

[PeWe]

Maybe Dynatek graphite wires? Grey....  Just cut and clamp an terminal plug for the coil.
http://www.gsparkplug.com/4x-ht-brass-push-in-terminal-for-distributor-coil-7mm-8mm-straight-crimp-type.html
This type was supplied with my Dynatek wire kit.
I had to purchase the crimp tool separate.

My Dynatek wire was crap! DW-800 Grey silicone, 8mm graphite suppression core (resistance in wire)
One wire had intermittent failure from the beginning. I mixed it up with ongoing carb jetting that was delayed due to one lead had intermittent function. Probably broken wire or bad connection in the spark plug cap.

I reused CU -wires I had home and used NGK 5 kohm caps. I ordered new wires and terminals from the company I linked too.
Thats in UK, quick and cheap shipping for me.

[Deltarider]

Graphite core wires is a no no on our bikes.

[Jerry Rxman Griffin aka MuthaF'er]

I installed what Dyna sold me. 3 ohm coils and the same wires (yellow on thye Dyna III and black on the Dyna 2000) with those pre-formed caps along with a Dyna III on one bike and a Dyna 2000 on the other. No resistors and everything is fine. Not sure why you say you need resistors? My thinking is why put on a high performance system and throttle the final output with resistors.

[Deltarider]

My experience with Dyna is not a good one. Decades ago I installed the green 3Ω Dyna coils with yellow Dynatek silicon wires. A lot of advertisement bla, bla of 36.000 Volts, but personally I've never experienced any improvement going from stock to Dyna. Now that I understand more of ignition systems, I know why. The only good thing one can say, is that you can renew the HT leads easily. Not that it helped me: one of the Dyna's was shot after only 30.000 kms. BTW the stock Toyo coils still live both after having served over 75.000 kms. The Dynatek silicon wires were and are fine though.
There is a lot of nonsense about widening gaps, higher voltages etc. Yes, the ignition needs a high enough voltage ofcourse to start the proces (stock coils are more than adequate for this!), but even important is enough burning time aka spark duration. When you gap wider than Honda recommends, you may create a higher initial voltage (that you don't need!) which will cause quicker erosion of the plug tips. Aiming for a higher voltage also will shorten the burning time. My preference would be a longer spark duration. With my homebuilt transistor ignition I have a spark duration of over 2000µs which equals a burning time of 36^o rotation. Another feature of my transistor ignition (which I admit is a blunt Velleman K2543 copycat) is, it will not fry my coils when I leave the ignition key switched on.
Hondaman can explain better than I why you need resistors. I still have my doubts but maybe the Dyna coil was ruined by running it for quite some time without resistor. I don't remember, it's too long ago. Better stay on the safe side and use resistors as there will be less oscillating ofcourse and you'll need some impedance anyway to ride legally.

[Gordo]

My experience with Dyna is not a good one. Decades ago I installed the green 3Ω Dyna coils with yellow Dynatek silicon wires. A lot of advertisement bla, bla of 36.000 Volts, but personally I've never experienced any improvement going from stock to Dyna. Now that I understand more of ignition systems, I know why. The only good thing one can say, is that you can renew the HT leads easily. Not that it helped me: one of the Dyna's was shot after only 30.000 kms. BTW the stock Toyo coils still live both after having served over 75.000 kms. The Dynatek silicon wires were and are fine though.
There is a lot of nonsense about widening gaps, higher voltages etc. Yes, the ignition needs a high enough voltage ofcourse to start the proces (stock coils are more than adequate for this!), but even important is enough burning time aka spark duration. When you gap wider than Honda recommends, you may create a higher initial voltage (that you don't need!) which will cause quicker erosion of the plug tips. Aiming for a higher voltage also will shorten the burning time. My preference would be a longer spark duration. With my selfbuilt transistor ignition I have a spark duration of over 2,5 milliseconds which equals a burning time of 36^o rotation @ 3000 rpm. Another feature of my transistor ignition (which is a blunt Velleman K2543 copycat btw), is it will not burn my coils when I leave the ignition key switched on.
Hondaman can explain better than I why you need resistors. I still have my doubts but maybe the Dyna coil was ruined by running it for quite some time without resistor. I don't remember, it's too long ago. Better stay on the safe side and use resistors as you'll need some impedance anyway to ride legally.

What way legal?

[Deltarider]

Here in Europe it's not legal to run ignitions that interfere with radio's.

[Gordo]

Good heads up I'm uk so worth knowing cheers

[Duke McDukiedook]

Maybe Dynatek graphite wires? Grey....  Just cut and clamp an terminal plug for the coil.
http://www.gsparkplug.com/4x-ht-brass-push-in-terminal-for-distributor-coil-7mm-8mm-straight-crimp-type.html
This type was supplied with my Dynatek wire kit.
I had to purchase the crimp tool separate.

My Dynatek wire was crap! DW-800 Grey silicone, 8mm graphite suppression core (resistance in wire)
One wire had intermittent failure from the beginning. I mixed it up with ongoing carb jetting that was delayed due to one lead had intermittent function. Probably broken wire or bad connection in the spark plug cap.

I reused CU -wires I had home and used NGK 5 kohm caps. I ordered new wires and terminals from the company I linked too.
Thats in UK, quick and cheap shipping for me.

Like PeWe I had better luck with copper core wire and NGK caps with my 3 ohm dyna coils. I installed a resistor pack like Hondaman suggested and it runs better. Just need to sort out my leaky #1 carb though.

[PeWe]

about coils...I started with Dyna 3 ohm coils... battery drained very quick so I went back to the shop and could make a switch to Dyna 5 ohm coils (black) The green 3 ohm coils has nothing to do on a street bike. Maybe possible if never having the headlight on....

[Deltarider]

about coils...I started with Dyna 3 ohm coils... battery drained very quick

I read this often here. I myself have never experienced this, so I'm curious and have planned a test by connecting an ammeter to find out how much a 3Ω coil set in total really draws, but... it will not be before next spring.

[madmtnmotors]

about coils...I started with Dyna 3 ohm coils... battery drained very quick

I read this often here. I myself have never experienced this, so I'm curious and have planned a test by connecting an ammeter to find out how much a 3Ω coil set in total really draws, but... it will not be before next spring.

I have 30,000 trouble free miles with Dyna 3ohm coils with Dyna wires as well.

[Deltarider]

I have 30,000 trouble free miles with Dyna 3ohm coils with Dyna wires as well.

I'm curious to know: 1) on what bike? 2) for the rest a stock ignition or have you added a ballast resistor in the 12V+ feed to the coils?

[madmtnmotors]

I have 30,000 trouble free miles with Dyna 3ohm coils with Dyna wires as well.

I'm curious to know: 1) on what bike? 2) for the rest a stock ignition or have you added a ballast resistor in the 12V+ feed to the coils?

1) My 1978 CB750K
2) Paired with DynaIII ignition (NLA), no resistor.

 I am also running 3ohm coils (also no resistor) on my 1978 CB750K dragbike with Dyna wires, Dyna S, and a Dyna 200DRL rev limiter. I have much fewer miles on the dragbike so far though... 

[Jerry Rxman Griffin aka MuthaF'er]

+1 on my 75 CB750F Dyna III and 3 ohm Dyna coils and Dyna non-resistor wires and non-resistor. 20,000+ miles

[PeWe]

My battery consuming experience was Dyna-S with 3 ohm coils. Headlight on drained battery. Ok with 5 ohm coils. This made me to order a LED that change color depending on voltage. Green is  OK , red too much, yellow too little. Flash when ignition is off so it look like an alarm and idnicate that battery is OK as long it flash green.

Later back to points and Hondaman ignition

[HondaMan]

The purpose of the resistors in the plug caps (and/or plugs, and/or wires) is to stretch out the spark DURATION longer, and in some cases, to cool off the coils a little bit (more of this on cars than on bikes). The SOHC4 engine desires a longer-duration spark, due to the swirl charge design: the longer the spark lasts, the longer, wider flamefront the spark ignites as the mixture whirls past the plug, and the longer the charge then burns to push on the piston, down the bore.

That, in a nutshell, is what it's about.

[Jerry Rxman Griffin aka MuthaF'er]

The purpose of the resistors in the plug caps (and/or plugs, and/or wires) is to stretch out the spark DURATION longer, and in some cases, to cool off the coils a little bit (more of this on cars than on bikes). The SOHC4 engine desires a longer-duration spark, due to the swirl charge design: the longer the spark lasts, the longer, wider flamefront the spark ignites as the mixture whirls past the plug, and the longer the charge then burns to push on the piston, down the bore.

That, in a nutshell, is what it's about.

Mark,

Since the chamber design on the -392 head is smooth compared to the earlier heads what's your take on the swirl charge and these heads? I'm assuming this is what you are referring to?? Hard to imagine this very quick bang either way. Milli seconds aren't very long regardless, huh. Interesting.

[PeWe]

Ported heads have also smoother, more hemi like chambers. Higher CR will work better with a specific spark, right? Both resistor plugs and resistor caps?

[garyS-NJ]

I always thought resistor spark plugs were to reduce emi to the electronic ignition and the radio (if equipped).  So old points bikes with no radios got plugs without an "R". My newer bikes have R plugs and my 1984 yam venture has R plugs AND 5k resistors in the plug caps.  On the yamaha, the plug wires themselves are 5-10k I think but then the coil secondary is only a few ohms.  The resistor in series I believe would act to round off sharp edges in the square'ish ignition pulse (& round off any spike).  These sharp edges have the high frequency components which might radiate to produce emi.  Btw, I put a Dyna-S in my '78 cb750f3 and used my stock coils, wires, caps, and plugs.  Bike seems to start easier and idle smoother but I'd swear I can feel it a tad more docile when I get on it hard (probably my imagination).  Not too many miles on the dyna here but note Dyna does not require the use of resistor plugs with their electronic ignition.. (Maybe R its are more important with complicated ECU's?).  I don't have many miles on the Dyna.  Oh, as to the original post, I would use the wire set that comes with the coils until it stops working..  And I never thought about my old bike needing a long duration spark but the MSD ignitions produce multiple sparks to achieve this and perhaps this change in spark duration is what I felt when going from points to the Dyna-S...  Is think that spark duration is inversely proportional to peak voltage and controlled by the inductance and resistance pair (coil and wire through cap and spark plug).  So Dyna MUST have a recommendation for plugs and caps with their ignition and coils! 

Sent from my VS987 using Tapatalk

[Deltarider]

What is discussed above about spark duration is mostly academic and the question remains if you'll ever feel the difference in every day life. I've not yet seen scope images that show a significant difference in burning time between 5K and 10K 'noise suppressers' as Honda calls them.
Best effect on your ignition IMO is: 1) a firm ride at sustained high speeds (at least 30 minutes) or 2) a new set of sparkplugs. A few degrees extra advance worked well for me too.
BTW, has any of you experimented with a knock sensor? Not for an ECU ofcourse, but I wonder if you could use it to make an idiot light burn in the event knocking occurs. I know it works by detecting the typical frequency where knocking begins (around 7,5KHz). They're cheap and I wonder if you could use them for a warning light.