What the sock?!

[Rob Valdez 79 R65]

Aluminium?
I have never owned a Dyna coil, but for some reason I thought that they would be of a higher standard, with copper in there.
I am disappointed.

I am very anal when it comes to electrical connectors.  I love copper, and dielectric (or any kind) of grease.

But, I suppose aluminium must be O.K., considering the path the ground takes from the battery to the starter. 

I can't say for sure, but I think my Bosch Blues had copper sleeves.  Definitely use the copper, solder-on type of butt connector for your plug wires.  I have no idea where to buy them.  Maybe buy some OEM wires and take them off them?
You are, after all, going to use NGK plug caps if you want to ride in the rain.

I reused my butt connectors many times.  They are so much better than then clamp-on butts with the little pointy thing that goes down and hopefully makes contact with the wire.

[mrclubike]

You cans till get the solder on style ends
part #12 12 8 536 120
I have a brand new pair but have not installed them yet

[Rob Valdez 79 R65]

You cans till get the solder on style ends
part #12 12 8 536 120
I have a brand new pair but have not installed them yet

[tunnelrider]

Hi all, I'm still investigating this oft brought up, probably boring for most topic of coils, since it's off the bike and while reading a lot of info on Snowbum's site (boy he's an electronic whiz), I came across this about green Dyna coil;

"Dyna sells many different coils. Do not use the Green dual-tower 6 volt coil with the Bosch electronic ignitions that came on the BMW Airheads from 1981.  Those Dyna coils are 3 ohms, and are marginal in that application."

As my (1994 Dyna) coil is green, 3ohms, how can you tell if it's 6V? Or is 6V because of two towers off one coil? I thought Dyna wouldn't sell 6V coils these days but may be wrong.
Anyhow it has obviously propelled her along for a good amount of time but thinking I might get a more even spark from a new one with lower primary resistance, more matched for the electronic ignition (if the black box can handle it!)

[georgesgiralt]

Tunnelrider,
Go to a car junk yard and find a dual output coil from a petrol car. Choose if possible a Fiat one (as they use Marelli parts with similar specs as the Bosch on our bikes). But of course other makes will do just fine.
Check the primary resistance just to be sure and use it. It will cost you dimes and will work "of the box"... as these are also devised for powerful electronic ignition.

[Barry]

....."Dyna sells many different coils. Do not use the Green dual-tower 6 volt coil with the Bosch electronic ignitions that came on the BMW Airheads from 1981.  Those Dyna coils are 3 ohms, and are marginal in that application."

As my (1994 Dyna) coil is green, 3ohms, how can you tell if it's 6V? Or is 6V because of two towers off one coil? I thought Dyna wouldn't sell 6V coils these days but may be wrong.

Snowbums reference to a Dyna green being 6 V sounds like a mistake to me so I wouldn't worry about running it on 12 V.

By marginal I guess he means with a 3 ohm coil you just have the spark energy of points ignitions instead of the greater energy provided by a 1.5 ohm coil normally used with electronic ignition. That's the theory but if the 3 ohm coil works well when everything is cleaned up you may not see any practical improvement with the correct coil.

[skippyc]

Voltage isn't important it all works on the resistance of the primary winding. 3ohms would work well on a 6V system.

[Barry]

I agree that ignition coils don't really have a measurable parameter called voltage but the applied voltage together with the primary resistance determines what current will flow. To that extent a coil intended for 6 voltage operation would work great on 12 volts as the primary current would nominally  be doubled and spark energy being proportional to the square of the primary current would increase 4 fold.  All provided the coil didn't overheat from more current than it was designed for.

Conversely if you used a 3 ohm coil intended for 12 volt operation on a 6 volt system the spark energy would be reduced 4 fold.

[georgesgiralt]

Yes, but bear in mind that the ICU has a limit on the current it can supply.
If the resistance of the coil is too low, the output circuitry of the ICU could fry.... So it is important not to deviate from the value of the OEM coil.

[tunnelrider]

Thanks to all of you who've replied, I will probably go to the wreckers and find a suitable coil as a comparison. The ICU on my bike seems to be an aftermarket one with the only discernible info "M055" and "P5028" so I'll assume that's good for transistorised ignition and find a coil of approx 1.5ohms, as the OEM was for '81 on.

[mrclubike]

Like everyone has mentioned stay with 1.5 ohms and higher and you should be OK
I have used all 3 different Dyna  coils 3 1.5 and 0.7 and currently using the green 3 Ohm and it runs just as good as the others
I am using the geeen because the delco ignition module doesn't shut off if the engine is not running with the key still on
so it doesn't over heat

[Justin B.]

To that extent a coil intended for 6 voltage operation would work great on 12 volts as the primary current would nominally  be doubled

I tried a lower resistance coil on my '71 240Z years back thinking the same thing and got about 30 miles and it died.  Some side-of-the-road troubleshooting made me suspect the points breaker arm got so hot it bent and the gap closed up.  I eye-ball gapped the points, got to where I was going, and had to do the same drill on the way home -  very irritating!  I put the original coil back in and all was right with the world...

[Motu]

I have used an ignition coil from a Mitsubishi Lancer.  Just take a look at any wasted spark coils on cars, pick which ever configuration suits. And check the ohms to see if it will work.

[tunnelrider]

Thanks to all for your really helpful replies and Mrclubike on having used the different primary resistance Dyna coils and have found the green to be no different as far as how well it works.  Considering this info, and Barry also said it's unlikely to make much difference, if the spark test works out ok for my cleaned up green Dyna I'll probably stick with it.
It's gonna take me another couple of weeks to get to the stage of being able to do a spark test but at least now the front cover's back on after the timing chain job, I've repainted a number of parts, put a donor engine's cylinders and pistons on (with new rings of course) and got a loose valve guide fixed. Other tasks await finishing like bending a coil bracket, headlight rebuild, new front brake hose, clutch cable, neutral switch and gear shift seal. Who would've thought a snapped timing chain would lead to all of this?