Topic: Quick Dyna Coils question for my 1975 CB400F

[Simon]

Quick Dyna Coils question for my 1975 CB400F

I am looking for new coils for my bike.
The original coils are 5 Ohm and I am now looking for 5 Ohm Dyna coils.
Dyna offers 2 different options for the 5 Ohm coils :

DC7-1 (5.0 Ohm primary resistance / 17 000 Ohm secondary resistance)

DC8-1 (5.0 Ohm primary resistance / 14 000 Ohm secondary resistance)

Does anybody know witch one I should use based on your experience?

Thanks guys.

Simon

PS: Go Habs Go!

[Duke McDukiedook]

Will they both fit in the harness?

[Simon]

I have been told that the DC8-1 can fit on the original bracket with a light modification.

I have no idea if the two models are identical or not but they sure look the same...


Simon

[Duke McDukiedook]

The Honda service manual should tell you what the original secondary resistance was, you would want to match that.

[Simon]

I:ll have to look that up, thanks.

Clymer and Haynes have no such info. Wish I had the Honda service manual handy...

One internet seller said DC8-1 should be the right Dyna coil for the CB400F. As allways in these situations, I like to have a second opinion.

Anyone ever upgraded their coils with the Dyna coils on their 400f?

S.

[Bodi]

The coils should be identical specs, I don't know where you got those secondary numbers. Both are 17.0K in my Dyna catalog.
The difference is in where the secondary sockets are located. The DC7-1 come straight out one side, OK for Harley and such. The DC8-1 come out at an angle. You need this to route the spark plug cables towards the front of the engine.
DC8-1 is correct for 5 ohm SOHC-4 use.

[Simon]

Thanks Bodi, that confirms it.

I got the specs from the Tynatek site.



Simon

[Bodi]

I guess they changed them somewhere, or it's a misprint in my old catalog.

[greasy j]

I am considering changing out the coils on my cb750. I still have the originals, but I have a Dyna EI.

what can I expect to get out of doing this, as opposed to just using stock coils?

and sometimes people use different ohm coils on their cb750's than they came with. like 2 or 3 instead of 5, I think.

can someone please explain?

Bodi, why are you changing yours out? performance or necessity?

thanks

thanks

[brandon]

I have DC8's. As stated they are at an angle because there is minimal room between the the top of the valve cover to the bottom of the coils where the spark plug wires connect.

[Bodi]

I put in the DC8-1 coils about 10 years ago because the original stock coil's HV cables were deteriorated and sparking to the frame and tank bottom. The Dyna's were the best replacement option I found. I have had a Martek 440 electronic ignition in this 400-4 for about 30 years.

[greasy j]

gotcha.

I'll read up in my hondaman 750 book and see what he says about coils.