400/4 build. Paused due to other commitments. But starting up again

[McCabe-Thiele (Ted)]

Hey Ted. Mine say 3 ohm on the other side.....i did see those ones you have....tbh i just search for 1977 honda cb 400 and these ones came up....

The packaging saying Drag Specialities just made me suspicious as you described them as Dyna ones - lots of other brands on the market that work - my 500 has some cheap ones purchased locally.

What I do like about the coils you have is the plug in leads I am no fan of the original Honda design. I would be interested to know the supplier if you have a link. Are the bolt centres the same as the original as well?

[ComfySofa]

Heres what i ordered....i searched for Dyna Coils....they do look and feel like Dyna coils....heavy in weight and the same feel (from what i remember) re the casing feel...

https://www.ebay.co.uk/itm/275541216292

My old GSXR ones (from recollection were yellow in colour) and had the same exit angle for the HT leads....i kinda assumed that they were therefore dyna...might not be though - i must confess i didnt pay that much attention...!

Furiously googling now....yeah appears i dont have actual "Dyna" ones....return or no? what says you lot?

Found them on the net.... https://www.arhcustom.co.uk/brands/drag-specialties/drag-specialties-ignition-coils/?gclid=CjwKCAjwu4WoBhBkEiwAojNdXnmGsixawd_6TrN-hooqUKsH8TrH0shry28nMxjlCQ24k7k2vX0AUhoCnRkQAvD_BwE

Anyone got any reviews/feeback??

Edit - found a range of reviews...cant see anything bad about them- different models but they all seem to be happy with them....and i will say they do have the look, feel and the weight of Dyna's..

[Oddjob]

Dynas do have some known faults. Normally the ohm resistance is wrong, that's been known to cause problems. The biggest drawback though is how much more power they consume than standard coils, can't remember offhand but do remember it being listed by Hondaman as excessive compared to stock. As the amount of power on the SOHC bikes is also a known issue any additional draw is best avoided if at all possible.

I'd have mounted them the other way Ted, facing forward you have wind etc pushing moisture into the opening where the leads exit, facing backward you don't. They should fit either way so why not take advantage of that.


Biggest drawback IMO is the cost, fixing the standard coils is normally miles cheaper and thanks to the Ash fix that's now easy to do. Plus then you get the correct impedance, lower current draw and better fitting. Along with electrical connectors are spot on.

[ComfySofa]

Well, - ive got a set of oem honda coils for sale (only done 6.2k)

[Oddjob]

Fix them, worth more and you never know what might happen in the future.

[McCabe-Thiele (Ted)]

Are the bolt centres as per the originals if they are I would probably keep them?
The Dynas are probably not worth paying the extra for imho.

That's the same firm I bought my complete Dyna electronic ignition from. As regards current use I thought that is down to the Dyna Electronics not the coils themselves.

[ComfySofa]

Still at the office so not sure yet...! i will get back with an answer..!

[SteveD CB500K0]

As regards current use I thought that is down to the Dyna Electronics not the coils themselves.

The issue is with the primary impedance Ted.

The standard coils are about 5 ohms, which at 12V is 2.4A or 29W when the points are closed.

3 ohm coils will draw 4A (48W) which could easily overload your alternator if you have lights on etc.

I’m writing this from memory so any errors will sin be reported by the (other) electronic engineers on here.


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[K2-K6]

You could open the points gap to wider than std in facilitating running the 3.0 Ohm coils.

Essentially the same that electronic switching does, they can then use less dwell time to reduce the draw and still make good sparks.

One way of almagamating the two different speciation elements.

[McCabe-Thiele (Ted)]

As regards current use I thought that is down to the Dyna Electronics not the coils themselves.

The issue is with the primary impedance Ted.

The standard coils are about 5 ohms, which at 12V is 2.4A or 29W when the points are closed.

3 ohm coils will draw 4A (48W) which could easily overload your alternator if you have lights on etc.

I’m writing this from memory so any errors will sin be reported by the (other) electronic engineers on here.


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No worries for me then it's unlikely I will  ever ride in the dark again plus my headlamp & rear lamps are LED's.

[ComfySofa]

Offering them up it looks to be ok....

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[McCabe-Thiele (Ted)]

I can't tell from the photo if you measure the distance between the holes on your original coil is it the same as the distance between the outer most holes on your replacement coil.
It look wider to me Andy?

As you can see in my photo I had to cut out the coil mounts to fit on the 400, my 500 coils were 10mm too short so I just inserted a link bracket to the frame as they are mounted differently.

[Oddjob]

It’s not just lights that draw large currents though Ted, sit at some lights with the indicator going and you’re holding the bike on the brakes so the rear light is lit etc and as the bikes ticking over almost no charge is going to the battery, all this drains even a good battery never mind a poor one. Plus these days it’s advisable to ride with lights on etc, you need to make sure your seen etc.

That’s the point I was trying to make, don’t forget there are small bulbs lit as well like neutral, repeaters, speedo/tacho etc, it all adds up

[McCabe-Thiele (Ted)]

It’s not just lights that draw large currents though Ted, sit at some lights with the indicator going and you’re holding the bike on the brakes so the rear light is lit etc and as the bikes ticking over almost no charge is going to the battery, all this drains even a good battery never mind a poor one. Plus these days it’s advisable to ride with lights on etc, you need to make sure your seen etc.

That’s the point I was trying to make, don’t forget there are small bulbs lit as well like neutral, repeaters, speedo/tacho etc, it all adds up

I have electronic flasher & LED indicators all my small bulbs are LED's as well plus I regualrly connect up my smart charger, my DTRL is also LED

[ComfySofa]

Coils fitted..they don't sit in the castings so bolted to the top...forgot to get a photo...do that when I get home...

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