GS1100E Dyna Coil Question

[Tourmaster]

I have a 1981 GS1100E and am experiencing very weak to no spark. Before I blame this issue on the coils, I plan to go through the complete ignition system diagnostic recommendations first. Excellent stuff on this, and BassCliff's site, BTW. May just be dirty contacts ... weak battery, etc, etc.

Anyway, my question concerns replacement coils. I've noticed guys recommending the Dyna Dual Output (Green) 3 Ohm coils as a good replacement option. Would this be the correct coil replacement for my bike? In the FSM, it indicates that my bike's primary winding comes in at the 3 -5 ohm range. Based on the Dynatek sites recommendations they state you shouldn't undersize these replacement coils. So, wouldn't something like their Dyna Dual Output (Black) 5 Ohm unit be a safer/better option?

And finally, assuming everything else in the ignition system was perfect, do these Dyna coils provide better spark intensity than the OEM coils? Also, are these Dyna coils easy to mount on the bike ... or will I have to do some modiying/drilling?

Just new here and have done a fair bit of searching around this excellent forum, but would really appreciate some clarification and advice on this.

[rapidray]

The green 3.0 ohm Dyna coils are the way to go, along with new Dyna plug wires at the same time. They bolt right to the stock mounting location but make sure you do the "coil relay mod" also when you install the new parts to make sure you have a true 12 volts getting to the coils. You will be amazed at the difference! Ray.

[posplayr]

I would do a coil relay modification, to power your entire ignition circuit from a relay. Yo ucan do a search; I have a writeup for "Yet another Coil Relay Mod" that incorporates a Dyna S

http://www.thegsresources.com/_forum/showthread.php?t=141055

Unfortunately the switches and conenctions in teh OEM electrical are just not of high enough quality to power the ignition, making Relay's nessesary

[Tourmaster]

Thanks Pos and Ray. I understand why the Coil Mod Relay ugrade will improve my spark intensity ... but why not just do this change if the OEM coils are still okay. Or ... do these Dyna coils also add a further improvement to the spark intensity? Just not fully clear on this yet.

Pos ... you mentioned that on your GS1100 that you also installed the Dyna S ignition. I assume that I can just first install the Dyna coils with the OEM ignition still in place, right? I believe my OEM ignition is still okay, however, would there be additional benefits to considering this upgrade also ... ie: improved cold starting, more power??? It's my understanding that the OEM ignition is unadjustable ... so with the Dyna S system, do you get some flexibility in further optimizing the timing?

I'm thinking of just cleaning up all the harness connections and grounds on this old bike and installing the Dyna coils and Coil Mod Relay first, and see where this takes me. Does this sound like a decent strategy?

Again, many thanks guys ... and you've already helped me out considerably. Cheers

[don_gibb6512]

Have you tested your practically 30 year old OEM coils yet? I'd bet money that they're crap by now. Your original ignition will work just fine with the Dyna coils and the relay mod but if you plan on keeping the bike for a long time, switching out to a new Dyna S ignition is just having the "peace of mind" knowing that it shouldn't die out at any given moment.

Good luck.

[Tourmaster]

Thanks Don. And, nope, haven't checked the coil winding resistance yet, but tis on my list.

[SqDancerLynn1]

There's no reason why you can't do the relay mod first!!!

[don_gibb6512]

Be sure to test the resistance on both the primary and secondary windings. I once had a set of Accel coils that bench tested ok but the voltage broke down under load in the secondary windings.

Good luck.

[Tourmaster]

Don ... yep, I see the FSM recommended coil test, so will be sure to follow it.

Sq .... So I take it, if my old coils check out okay, then the Coil Relay Mod will be sufficient. So can I deduce from this comment that the Dyna Coils are no better than the OEM coils when in decent condition?

The reason I keep asking this question relates to my more extensive knowledge of the DOHC CB750's of similar vintage. There is a replacement coil for these bikes that is an improvement over the OEM version ... resulting in a sharper spark. So ... once again, do the Dyna Coils provide superior spark intensity over the OEM coils in good condition? If not ... then SqDancer makes a good point.

Thanks again guys ... and I'm learning every step of the way.

[posplayr]

I'm thinking of just cleaning up all the harness connections and grounds on this old bike and installing the Dyna coils and Coil Mod Relay first, and see where this takes me. Does this sound like a decent strategy?

Again, many thanks guys ... and you've already helped me out considerably. Cheers

This is what i would do for sure; Coils are probably more important than Dyna S and Coil Mod probably more important than either

[posplayr]

Don ... yep, I see the FSM recommended coil test, so will be sure to follow it.

Sq .... So I take it, if my old coils check out okay, then the Coil Relay Mod will be sufficient. So can I deduce from this comment that the Dyna Coils are no better than the OEM coils when in decent condition?

The reason I keep asking this question relates to my more extensive knowledge of the DOHC CB750's of similar vintage. There is a replacement coil for these bikes that is an improvement over the OEM version ... resulting in a sharper spark. So ... once again, do the Dyna Coils provide superior spark intensity over the OEM coils in good condition? If not ... then SqDancer makes a good point.

Thanks again guys ... and I'm learning every step of the way.

I did not do a coil mod on my 81 GS750 but it does have OEM coils. The spark at tick over is feeble to say the least.

My ED with Accel coils and coil relay mod is big blue flame.

[Turtleface]

I did not do a coil mod on my 81 GS750 but it does have OEM coils. The spark at tick over is feeble to say the least.

My ED with Accel coils and coil relay mod is big blue flame.

Dyna Greens and the relay mod left my hand numb for about five minutes. It's really not wise to be holding the spark plug lead while cranking over an engine.

[rapidray]

It's really not wise to be holding the spark plug lead while cranking over an engine.

It's fun to let an unsuspecting friend do it though!!! Ray.

[Tourmaster]

Thanks for all the great advice guys.

[Tourmaster]

Hey guys ... I do have one final question concerning plug wires. Will probably go with the Dyna 3 ohm coils recommended here, but was wondering about the correct plug wires. If I go with the Dyna plug wire and cap kits ... question is, should I purchase 7mm or 8mm? ... and should they be suppression or non-suppression (copper core) type?

Since I am running non-resistor OEM plugs on my bike, I assume that the best choice would be the 8mm suppression type Dyna kit (DW800).

Is this the right way to go ... or does it really matter?