Dyna III. Aftermarket 5 Ohm Coil Options? And Resistance.

[Tom H]

I'm considering running a Dyna III setup. I'm looking for aftermarket coil options. I know the Dyna 5 Ohm black coils would probably be best, but expensive.

What brand and model number 5 Ohm coils can be had at an auto parts store?

BTW: I did do a search for this info, but couldn't find what I'm looking for.

Thank you,
Tom

[Testarossa]

Guzziology recommends 3-ohm (see section 6-33). Actual resistance is 3.3 ohms, and actual resistance of 5 ohm coils is about 4.5, so there's really not enough difference to worry about. Dyna coils are way overpriced.

I use this on both my Dyna III Guzzis: https://www.amazon.com/Bosch-00012-9220081083-Ignition-Coil/dp/B001CO4WA2 This may have been original equipment on the 850T and the coils on mine have lasted at least 50,000 miles. But the Haynes manual lists a Marelli 3.3 ohm coil as original equipment for early big twins.

[kirby1923]

FWIW

My CX has about 35K on dual head(plugs) w/3 ohm and they have outlasted the black box Dyna III ,( 25 years.)

:-)

[Charles in Lake Charles]

I just run the original Marelli 3.3 ohm coils.

[Tom H]

It looks like the 3 ohm coils will work from the replies so far. This is the info I had from doing a search here. But the Dyna 5 ohm blacks were also often mentioned and recommended if someone was having issues.

I did do a search at amazon. Found some Honda coils that are shaped like the Dyna's that might do the trick, cheap too. But again, it may be a get what you pay for item??

I'm really looking for something that's available at most auto parts stores with 5 ohm. But then again, a Bosch Blue or old VW generic can be had there.

As a side note. Is there a part number for the Tonti style small 3 ohm coils that auto parts stores carry??

Thank you,
Tom

[Tom H]

73 Sport,

I did read that on their site. That's why I would prefer the 5 ohm coils. But at the same time, many have used the 3 ohm stock Guzzi coils with good results.

I'm looking at options in case I decide to stay with Dyna. Could just revert to dual points and be done with it?????

Thank you!
Tom

[Antietam Classic Cycle]

It looks like the 3 ohm coils will work from the replies so far. This is the info I had from doing a search here. But the Dyna 5 ohm blacks were also often mentioned and recommended if someone was having issues.

I did do a search at amazon. Found some Honda coils that are shaped like the Dyna's that might do the trick, cheap too. But again, it may be a get what you pay for item??

I'm really looking for something that's available at most auto parts stores with 5 ohm. But then again, a Bosch Blue or old VW generic can be had there.

As a side note. Is there a part number for the Tonti style small 3 ohm coils that auto parts stores carry??

Thank you,
Tom

For street use, I recommend the black 5 ohm Dynas over the green 3 ohms due to the latters propensity to overheat easily and crack.

But, I think you'll be fine using any other brand of 3 ohm coil. I doubt any auto parts will have a coil as small as the originals.

I'd avoid any oil filled coil. I'd recommend using either the Bosch Blue Coil or the Pertronix Flame Thrower coil. The Pertronix can be found at Advance Auto, IIRC.

Bosch Blues are available on Amazon: https://www.amazon.com/Bosch-00012-9220081083-Ignition-Coil/dp/B001CO4WA2

[moto-uno]

  The Accel 5 ohm coils have worked really well on my twin plugged Le Mans 2 for the last 3 decades .
  They have a lifetime guarantee ( which is good 'cuz as well as they work , every decade or so I've had
  to replace one . Keep your sales receipt :) ) . They do work well though .   Peter

[Testarossa]

For a number of years I commuted on the 850T, with a lot of heavy traffic in hot weather. The 3.3 ohm Blue Bosch coils never failed.

[Tom H]

With the advise, I'm still thinking about the coils.

Has anyone tried the Magna brand Dyna knock offs? Look the same and price is much lower.

Tom

[Tom H]

I did find a standard style coil, about the same size as Bosch Blue or maybe a tad smaller. Emgo 24-71522. Not available in auto parts, but does have 5.5K Ohm.

I do have a question about secondary resistance. What would be better to have 10K, 14K or 17K Ohm?? IIRR Dyna black is 14Kohm.

Thanks again,
Tom

[wrbix]

Don’t have my copy handy, but I recollect that Guzziology did recommend Pertronix Flame Thrower. Anyone confirm that?

[moto-uno]

  ^^ The secondary with a higher resistance "should have" the potential for a greater spark energy . Peter

[Tom H]

The Should Have wording kinda made me wonder. So I spent about 3 hours searching what why low or high secondary resistance does.

After reading a lot on many sites. One set of sites I thought said that high resistance gave a bad spark. Another set said higher is better. The only thing I did find was that if your secondary generally test less than 10Kohms, it's going bad. But then again, many new coils have that or less?

The Dyna black S/B 14k
The Emgo S/B 10k
The Magna S/B 17k
The Bosch Blue S/B about 9k

I am going to run a pair of Bosh Blue for now. Still looking and still confused.
Tom

[Rough Edge racing]

With the advise, I'm still thinking about the coils.

Has anyone tried the Magna brand Dyna knock offs? Look the same and price is much lower.

Tom

  I have the Dyna type knockoffs on my Triumph 750...They do the job...

[baloo]

It looks like the 3 ohm coils will work from the replies so far. This is the info I had from doing a search here. But the Dyna 5 ohm blacks were also often mentioned and recommended if someone was having issues.

I did do a search at amazon. Found some Honda coils that are shaped like the Dyna's that might do the trick, cheap too. But again, it may be a get what you pay for item??

I'm really looking for something that's available at most auto parts stores with 5 ohm. But then again, a Bosch Blue or old VW generic can be had there.

As a side note. Is there a part number for the Tonti style small 3 ohm coils that auto parts stores carry??

Thank you,
Tom

Tom,
Did you ever try those cheap ohm Honda coils?
Thanks.

[Tom H]

No I never did. I have a 1000cc roundfin engine in a Loop that had the dual point dist. with Dyna. The coil installation was a mess with the big Bosch coils., Could have cleaned it up a bit. But I ended up just going with the single point dist..

Tom